Pull request for branch for-master/doc

index ffb6fb9..9685667 100644
@@ -8,6 +8,9 @@ The Buildroot user manual
 Buildroot usage and documentation by Thomas Petazzoni. Contributions
 from Karsten Kruse, Ned Ludd, Martin Herren and others.
 
+Buildroot {sys:echo $\{BR2_VERSION%%-git*\}} manual generated on {docdate}
+{doctime} from git revision {sys:git rev-parse --short HEAD}
+
 image::logo.png[]
 
 :leveloffset: 1

new file mode 100644
index 0000000..0704cc0
@@ -0,0 +1,3772 @@
+# This is Kconfiglib, a Python library for scripting, debugging, and extracting
+# information from Kconfig-based configuration systems. To view the
+# documentation, run
+#
+#  $ pydoc kconfiglib
+#
+# or, if you prefer HTML,
+#
+#  $ pydoc -w kconfiglib
+#
+# The examples/ subdirectory contains examples, to be run with e.g.
+#
+#  $ make scriptconfig SCRIPT=Kconfiglib/examples/print_tree.py
+#
+# Look in testsuite.py for the test suite.
+
+"""
+Kconfiglib is a Python library for scripting and extracting information from
+Kconfig-based configuration systems. Features include the following:
+
+ - Symbol values and properties can be looked up and values assigned
+   programmatically.
+ - .config files can be read and written.
+ - Expressions can be evaluated in the context of a Kconfig configuration.
+ - Relations between symbols can be quickly determined, such as finding all
+   symbols that reference a particular symbol.
+ - Highly compatible with the scripts/kconfig/*conf utilities. The test suite
+   automatically compares outputs between Kconfiglib and the C implementation
+   for a large number of cases.
+
+For the Linux kernel, scripts are run using
+
+ $ make scriptconfig SCRIPT=<path to script> [SCRIPT_ARG=<arg>]
+
+Running scripts via the 'scriptconfig' target ensures that required environment
+variables (SRCARCH, ARCH, srctree, KERNELVERSION, etc.) are set up correctly.
+Alternative architectures can be specified like for other 'make *config'
+targets:
+
+ $ make scriptconfig ARCH=mips SCRIPT=<path to script> [SCRIPT_ARG=<arg>]
+
+The script will receive the name of the Kconfig file to load in sys.argv[1].
+(As of Linux 3.7.0-rc8 this is always "Kconfig" from the kernel top-level
+directory.) If an argument is provided with SCRIPT_ARG, it will appear in
+sys.argv[2].
+
+To get an interactive Python prompt with Kconfiglib preloaded and a Config
+object 'c' created, use
+
+ $ make iscriptconfig [ARCH=<architecture>]
+
+Kconfiglib requires Python 2. For (i)scriptconfig the command to run the Python
+interpreter can be passed in the environment variable PYTHONCMD (defaults to
+'python'; PyPy works too and is a bit faster).
+
+Look in the examples/ subdirectory for examples, which can be run with e.g.
+
+ $ make scriptconfig SCRIPT=Kconfiglib/examples/print_tree.py
+
+or
+
+ $ make scriptconfig SCRIPT=Kconfiglib/examples/help_grep.py SCRIPT_ARG="kernel"
+
+Look in testsuite.py for the test suite.
+
+Credits: Written by Ulf "Ulfalizer" Magnusson
+
+Send bug reports, suggestions and other feedback to kconfiglib at gmail.com .
+Don't wrestle with internal APIs. Tell me what you need and I might add it in a
+safe way as a client API instead."""
+
+# If you have Psyco installed (32-bit installations, Python <= 2.6 only),
+# setting this to True (right here, not@runtime) might give a nice speedup.
+# (22% faster for parsing arch/x86/Kconfig and 58% faster for evaluating all
+# symbols in it without a .config on my Core Duo.)
+use_psyco = False
+
+import os
+import re
+import string
+import sys
+
+class Config():
+
+    """Represents a Kconfig configuration, e.g. for i386 or ARM. This is the
+    set of symbols and other items appearing in the configuration together with
+    their values. Creating any number of Config objects -- including for
+    different architectures -- is safe; Kconfiglib has no global state."""
+
+    #
+    # Public interface
+    #
+
+    def __init__(self,
+                 filename = "Kconfig",
+                 base_dir = "$srctree",
+                 print_warnings = True,
+                 print_undef_assign = False):
+        """Creates a new Config object, representing a Kconfig configuration.
+        Raises Kconfig_Syntax_Error on syntax errors.
+
+        filename (default: "Kconfig") -- The base Kconfig file of the
+                 configuration. For the Linux kernel, this should usually be be
+                 "Kconfig" from the top-level directory, as environment
+                 variables will make sure the right Kconfig is included from
+                 there (usually arch/<architecture>/Kconfig). If you are using
+                 kconfiglib via 'make scriptconfig' the filename of the
+                 correct Kconfig will be in sys.argv[1].
+
+        base_dir (default: "$srctree") -- The base directory relative to which
+                'source' statements within Kconfig files will work. For the
+                Linux kernel this should be the top-level directory of the
+                kernel tree. $-references to environment variables will be
+                expanded.
+
+                The environment variable 'srctree' is set by the Linux makefiles
+                to the top-level kernel directory. A default of "." would not
+                work if an alternative build directory is used.
+
+        print_warnings (default: True) -- Set to True if warnings related to
+                       this configuration should be printed to stderr. This can
+                       be changed later with Config.set_print_warnings(). It is
+                       provided as a constructor argument since warnings might
+                       be generated during parsing.
+
+        print_undef_assign (default: False) -- Set to True if informational
+                           messages related to assignments to undefined symbols
+                           should be printed to stderr for this configuration.
+                           Can be changed later with
+                           Config.set_print_undef_assign()."""
+
+        # The set of all symbols, indexed by name (a string)
+        self.syms = {}
+
+        # The set of all defined symbols in the configuration in the order they
+        # appear in the Kconfig files. This excludes the special symbols n, m,
+        # and y as well as symbols that are referenced but never defined.
+        self.kconfig_syms = []
+
+        # The set of all named choices (yes, choices can have names), indexed
+        # by name (a string)
+        self.named_choices = {}
+
+        def register_special_symbol(type, name, value):
+            sym = Symbol()
+            sym.is_special_ = True
+            sym.is_defined_ = True
+            sym.config = self
+            sym.name = name
+            sym.type = type
+            sym.cached_value = value
+            self.syms[name] = sym
+            return sym
+
+        # The special symbols n, m and y, used as shorthand for "n", "m" and
+        # "y"
+        self.n = register_special_symbol(TRISTATE, "n", "n")
+        self.m = register_special_symbol(TRISTATE, "m", "m")
+        self.y = register_special_symbol(TRISTATE, "y", "y")
+
+        # DEFCONFIG_LIST uses this
+        register_special_symbol(STRING, "UNAME_RELEASE", os.uname()[2])
+
+        # The symbol with "option defconfig_list" set, containing a list of
+        # default .config files
+        self.defconfig_sym = None
+
+        # See Symbol.get_(src)arch()
+        self.arch    = os.environ.get("ARCH")
+        self.srcarch = os.environ.get("SRCARCH")
+
+        # See Config.__init__(). We need this for get_defconfig_filename().
+        self.srctree = os.environ.get("srctree")
+        if self.srctree is None:
+            self.srctree = "."
+
+        self.filename = filename
+        self.base_dir = _strip_trailing_slash(os.path.expandvars(base_dir))
+
+        # The 'mainmenu' text
+        self.mainmenu_text = None
+
+        # The filename of the most recently loaded .config file
+        self.config_filename = None
+
+        # The textual header of the most recently loaded .config, uncommented
+        self.config_header = None
+
+        self.print_warnings = print_warnings
+        self.print_undef_assign = print_undef_assign
+
+        # Lists containing all choices, menus and comments in the configuration
+
+        self.choices = []
+        self.menus = []
+        self.comments = []
+
+        # For parsing routines that stop when finding a line belonging to a
+        # different construct, these holds that line and the tokenized version
+        # of that line. The purpose is to avoid having to re-tokenize the line,
+        # which is inefficient and causes problems when recording references to
+        # symbols.
+        self.end_line = None
+        self.end_line_tokens = None
+
+        # See the comment in _parse_expr().
+        self.parse_expr_cur_sym_or_choice = None
+        self.parse_expr_line = None
+        self.parse_expr_filename = None
+        self.parse_expr_linenr = None
+        self.parse_expr_transform_m = None
+
+        # Parse the Kconfig files
+        self.top_block = self._parse_file(filename, None, None, None)
+
+        # Build Symbol.dep for all symbols
+        self._build_dep()
+
+    def load_config(self, filename, replace = True):
+        """Loads symbol values from a file in the familiar .config format.
+           Equivalent to calling Symbol.set_user_value() to set each of the
+           values.
+
+           filename -- The .config file to load. $-references to environment
+                       variables will be expanded. For scripts to work even
+                       when an alternative build directory is used with the
+                       Linux kernel, you need to refer to the top-level kernel
+                       directory with "$srctree".
+
+           replace (default: True) -- True if the configuration should replace
+                   the old configuration; False if it should add to it."""
+
+        def warn_override(filename, linenr, name, old_user_val, new_user_val):
+            self._warn("overriding the value of {0}. "
+                       'Old value: "{1}", new value: "{2}".'
+                        .format(name, old_user_val, new_user_val),
+                       filename,
+                       linenr)
+
+        filename = os.path.expandvars(filename)
+
+        # Put this first so that a missing file doesn't screw up our state
+        line_feeder = _FileFeed(_get_lines(filename), filename)
+
+        self.config_filename = filename
+
+        # Invalidate everything. This is usually faster than finding the
+        # minimal set of symbols that needs to be invalidated, as nearly all
+        # symbols will tend to be affected anyway.
+        if replace:
+            self.unset_user_values()
+        else:
+            self._invalidate_all()
+
+        # Read header
+
+        self.config_header = None
+
+        def is_header_line(line):
+            return line.startswith("#") and \
+                   not unset_re.match(line)
+
+        first_line = line_feeder.get_next()
+
+        if first_line is None:
+            return
+
+        if not is_header_line(first_line):
+            line_feeder.go_back()
+        else:
+            self.config_header = first_line[1:]
+
+            # Read remaining header lines
+            while 1:
+                line = line_feeder.get_next()
+
+                if line is None:
+                    break
+
+                if not is_header_line(line):
+                    line_feeder.go_back()
+                    break
+
+                self.config_header += line[1:]
+
+            # Remove trailing newline
+            if self.config_header.endswith("\n"):
+                self.config_header = self.config_header[:-1]
+
+        # Read assignments
+
+        filename = line_feeder.get_filename()
+
+        while 1:
+            line = line_feeder.get_next()
+            if line is None:
+                return
+
+            linenr = line_feeder.get_linenr()
+
+            line = line.strip()
+
+            set_re_match = set_re.match(line)
+            if set_re_match:
+                name, val = set_re_match.groups()
+                # The unescaping producedure below should be safe since " can
+                # only appear as \" inside the string
+                val = _strip_quotes(val, line, filename, linenr)\
+                      .replace('\\"', '"').replace("\\\\", "\\")
+                if name in self.syms:
+                    sym = self.syms[name]
+
+                    old_user_val = sym.user_val
+                    if old_user_val is not None:
+                        warn_override(filename, linenr, name, old_user_val, val)
+
+                    if sym.is_choice_symbol_:
+                        user_mode = sym.parent.user_mode
+                        if user_mode is not None and user_mode != val:
+                            self._warn("assignment to {0} changes mode of containing "
+                                       'choice from "{1}" to "{2}".'
+                                       .format(name, val, user_mode),
+                                       filename,
+                                       linenr)
+
+                    sym._set_user_value_no_invalidate(val, True)
+
+                else:
+                    self._undef_assign('attempt to assign the value "{0}" to the '
+                                       "undefined symbol {1}."
+                                       .format(val, name),
+                                       filename,
+                                       linenr)
+
+            else:
+                unset_re_match = unset_re.match(line)
+                if unset_re_match:
+                    name = unset_re_match.group(1)
+                    if name in self.syms:
+                        sym = self.syms[name]
+
+                        old_user_val = sym.user_val
+                        if old_user_val is not None:
+                            warn_override(filename, linenr, name, old_user_val, "n")
+
+                        sym._set_user_value_no_invalidate("n", True)
+
+    def write_config(self, filename, header = None):
+        """Writes out symbol values in the familiar .config format.
+
+           filename -- The filename under which to save the configuration.
+
+           header (default: None) -- A textual header that will appear at the
+                  beginning of the file, with each line commented out
+                  automatically. None means no header."""
+
+        # already_written is set when _make_conf() is called on a symbol, so
+        # that symbols defined in multiple locations only get one entry in the
+        # .config. We need to reset it prior to writing out a new .config.
+        for sym in self.syms.itervalues():
+            sym.already_written = False
+
+        with open(filename, "w") as f:
+            # Write header
+            if header is not None:
+                f.write(_comment(header))
+                f.write("\n")
+
+            # Write configuration.
+            # (You'd think passing a list around to all the nodes and appending
+            # to it to avoid copying would be faster, but it's actually a lot
+            # slower with PyPy, and about as fast with Python. Passing the file
+            # around is slower too.)
+            f.write("\n".join(self.top_block._make_conf()))
+            f.write("\n")
+
+    def get_kconfig_filename(self):
+        """Returns the name of the (base) kconfig file this configuration was
+        loaded from."""
+        return self.filename
+
+    def get_arch(self):
+        """Returns the value the environment variable ARCH had at the time the
+        Config instance was created, or None if ARCH was not set. For the
+        kernel, this corresponds to the architecture being built for, with
+        values such as "i386" or "mips"."""
+        return self.arch
+
+    def get_srcarch(self):
+        """Returns the value the environment variable SRCARCH had at the time
+        the Config instance was created, or None if SRCARCH was not set. For
+        the kernel, this corresponds to the arch/ subdirectory containing
+        architecture-specific source code."""
+        return self.srcarch
+
+    def get_srctree(self):
+        """Returns the value the environment variable srctree had at the time
+        the Config instance was created, or None if srctree was not defined.
+        This variable points to the source directory and is used when building
+        in a separate directory."""
+        return self.srctree
+
+    def get_config_filename(self):
+        """Returns the name of the most recently loaded configuration file, or
+        None if no configuration has been loaded."""
+        return self.config_filename
+
+    def get_mainmenu_text(self):
+        """Returns the text of the 'mainmenu' statement (with $-references to
+        symbols replaced by symbol values), or None if the configuration has no
+        'mainmenu' statement."""
+        return None if self.mainmenu_text is None else \
+          self._expand_sym_refs(self.mainmenu_text)
+
+    def get_defconfig_filename(self):
+        """Returns the name of the defconfig file, which is the first existing
+        file in the list given in a symbol having 'option defconfig_list' set.
+        $-references to symbols will be expanded ("$FOO bar" -> "foo bar" if
+        FOO has the value "foo"). Returns None in case of no defconfig file.
+        Setting 'option defconfig_list' on multiple symbols currently results
+        in undefined behavior.
+
+        If the environment variable 'srctree' was set when the Config was
+        created, get_defconfig_filename() will first look relative to that
+        directory before looking in the current directory; see
+        Config.__init__()."""
+
+        if self.defconfig_sym is None:
+            return None
+
+        for (filename, cond_expr) in self.defconfig_sym.def_exprs:
+            if self._eval_expr(cond_expr) == "y":
+                filename = self._expand_sym_refs(filename)
+
+                # We first look in $srctree. os.path.join() won't work here as
+                # an absolute path in filename would override $srctree.
+                srctree_filename = os.path.normpath(self.srctree + "/" + filename)
+                if os.path.exists(srctree_filename):
+                    return srctree_filename
+
+                if os.path.exists(filename):
+                    return filename
+
+        return None
+
+    def get_symbol(self, name):
+        """Returns the symbol with name 'name', or None if no such symbol
+        appears in the configuration. An alternative shorthand is conf[name],
+        where conf is a Config instance, though that will instead raise
+        KeyError if the symbol does not exist."""
+        return self.syms.get(name)
+
+    def get_top_level_items(self):
+        """Returns a list containing the items (symbols, menus, choice
+        statements and comments) at the top level of the configuration -- that
+        is, all items that do not appear within a menu or choice. The items
+        appear in the same order as within the configuration."""
+        return self.top_block.get_items()
+
+    def get_symbols(self, all_symbols = True):
+        """Returns a list of symbols from the configuration. An alternative for
+        iterating over all defined symbols (in the order of definition) is
+
+        for sym in config:
+            ...
+
+        which relies on Config implementing __iter__() and is equivalent to
+
+        for sym in config.get_symbols(False):
+            ...
+
+        all_symbols (default: True) -- If True, all symbols - including special
+                    and undefined symbols - will be included in the result, in
+                    an undefined order. If False, only symbols actually defined
+                    and not merely referred to in the configuration will be
+                    included in the result, and will appear in the order that
+                    they are defined within the Kconfig configuration files."""
+        return self.syms.values() if all_symbols else self.kconfig_syms
+
+    def get_choices(self):
+        """Returns a list containing all choice statements in the
+        configuration, in the order they appear in the Kconfig files."""
+        return self.choices
+
+    def get_menus(self):
+        """Returns a list containing all menus in the configuration, in the
+        order they appear in the Kconfig files."""
+        return self.menus
+
+    def get_comments(self):
+        """Returns a list containing all comments in the configuration, in the
+        order they appear in the Kconfig files."""
+        return self.comments
+
+    def eval(self, s):
+        """Returns the value of the expression 's' -- where 's' is represented
+        as a string -- in the context of the configuration. Raises
+        Kconfig_Syntax_Error if syntax errors are detected in 's'.
+
+        For example, if FOO and BAR are tristate symbols at least one of which
+        has the value "y", then config.eval("y && (FOO || BAR)") => "y"
+
+        This functions always yields a tristate value. To get the value of
+        non-bool, non-tristate symbols, use Symbol.get_value().
+
+        The result of this function is consistent with how evaluation works for
+        conditional expressions in the configuration as well as in the C
+        implementation. "m" and m are rewritten as '"m" && MODULES' and 'm &&
+        MODULES', respectively, and a result of "m" will get promoted to "y" if
+        we're running without modules."""
+        return self._eval_expr(self._parse_expr(self._tokenize(s, True), # Feed
+                                                None, # Current symbol or choice
+                                                s))   # line
+
+    def get_config_header(self):
+        """Returns the (uncommented) textual header of the .config file most
+        recently loaded with load_config(). Returns None if no .config file has
+        been loaded or if the most recently loaded .config file has no header.
+        The header comprises all lines up to but not including the first line
+        that either
+
+        1. Does not start with "#"
+        2. Has the form "# CONFIG_FOO is not set."
+        """
+        return self.config_header
+
+    def get_base_dir(self):
+        """Returns the base directory relative to which 'source' statements
+        will work, passed as an argument to Config.__init__()."""
+        return self.base_dir
+
+    def set_print_warnings(self, print_warnings):
+        """Determines whether warnings related to this configuration (for
+        things like attempting to assign illegal values to symbols with
+        Symbol.set_user_value()) should be printed to stderr.
+
+        print_warnings -- True if warnings should be
+                          printed, otherwise False."""
+        self.print_warnings = print_warnings
+
+    def set_print_undef_assign(self, print_undef_assign):
+        """Determines whether informational messages related to assignments to
+        undefined symbols should be printed to stderr for this configuration.
+
+        print_undef_assign -- If True, such messages will be printed."""
+        self.print_undef_assign = print_undef_assign
+
+    def __getitem__(self, key):
+        """Returns the symbol with name 'name'. Raises KeyError if the symbol
+        does not appear in the configuration."""
+        return self.syms[key]
+
+    def __iter__(self):
+        """Convenience function for iterating over the set of all defined
+        symbols in the configuration, used like
+
+        for sym in conf:
+            ...
+
+        The iteration happens in the order of definition within the Kconfig
+        configuration files. Symbols only referred to but not defined will not
+        be included, nor will the special symbols n, m, and y. If you want to
+        include such symbols as well, see config.get_symbols()."""
+        return iter(self.kconfig_syms)
+
+    def unset_user_values(self):
+        """Resets the values of all symbols, as if Config.load_config() or
+        Symbol.set_user_value() had never been called."""
+        for sym in self.syms.itervalues():
+            sym._unset_user_value_no_recursive_invalidate()
+
+    def __str__(self):
+        """Returns a string containing various information about the Config."""
+        return _sep_lines("Configuration",
+                          "File                                   : " + self.filename,
+                          "Base directory                         : " + self.base_dir,
+                          "Value of $ARCH at creation time        : " +
+                            ("(not set)" if self.arch is None else self.arch),
+                          "Value of $SRCARCH at creation time     : " +
+                            ("(not set)" if self.srcarch is None else self.srcarch),
+                          "Source tree (derived from $srctree;",
+                          "defaults to '.' if $srctree isn't set) : " + self.srctree,
+                          "Most recently loaded .config           : " +
+                            ("(no .config loaded)" if self.config_filename is None else
+                             self.config_filename),
+                          "Print warnings                         : " +
+                            bool_str[self.print_warnings],
+                          "Print assignments to undefined symbols : " +
+                            bool_str[self.print_undef_assign])
+
+
+    #
+    # Private methods
+    #
+
+    def _invalidate_all(self):
+        for sym in self.syms.itervalues():
+            sym._invalidate()
+
+    def _tokenize(self,
+                  s,
+                  for_eval = False,
+                  filename = None,
+                  linenr = None):
+        """Returns a _Feed instance containing tokens derived from the string
+        's'. Registers any new symbols encountered (via _sym_lookup()).
+
+        (I experimented with a pure regular expression implementation, but it
+        came out slower, less readable, and wouldn't have been as flexible.)
+
+        for_eval -- True when parsing an expression for a call to
+                    Config.eval(), in which case we should not treat the first
+                    token specially nor register new symbols."""
+        s = s.lstrip()
+        if s == "" or s[0] == "#":
+            return _Feed([])
+
+        if for_eval:
+            i = 0 # The current index in the string being tokenized
+            previous = None # The previous token seen
+            tokens = []
+        else:
+            # The initial word on a line is parsed specially. Let
+            # command_chars = [A-Za-z0-9_]. Then
+            #  - leading non-command_chars characters on the line are ignored, and
+            #  - the first token consists the following one or more command_chars
+            #    characters.
+            # This is why things like "----help--" are accepted.
+
+            initial_token_match = initial_token_re.match(s)
+            if initial_token_match is None:
+                return _Feed([])
+            # The current index in the string being tokenized
+            i = initial_token_match.end()
+
+            keyword = keywords.get(initial_token_match.group(1))
+            if keyword is None:
+                # We expect a keyword as the first token
+                _tokenization_error(s, len(s), filename, linenr)
+            if keyword == T_HELP:
+                # Avoid junk after "help", e.g. "---", being registered as a
+                # symbol
+                return _Feed([T_HELP])
+            tokens = [keyword]
+            previous = keyword
+
+        # _tokenize() is a hotspot during parsing, and this speeds things up a
+        # bit
+        strlen = len(s)
+        append = tokens.append
+
+        # Main tokenization loop. (Handles tokens past the first one.)
+        while i < strlen:
+            # Test for an identifier/keyword preceded by whitespace first; this
+            # is the most common case.
+            id_keyword_match = id_keyword_re.match(s, i)
+            if id_keyword_match:
+                # We have an identifier or keyword. The above also stripped any
+                # whitespace for us.
+                name = id_keyword_match.group(1)
+                # Jump past it
+                i = id_keyword_match.end()
+
+                # Keyword?
+                keyword = keywords.get(name)
+                if keyword is not None:
+                    append(keyword)
+                # What would ordinarily be considered a name is treated as a
+                # string after certain tokens.
+                elif previous in string_lex:
+                    append(name)
+                else:
+                    # We're dealing with a symbol. _sym_lookup() will take care
+                    # of allocating a new Symbol instance if it's the first
+                    # time we see it.
+                    sym = self._sym_lookup(name, not for_eval)
+
+                    if previous == T_CONFIG or previous == T_MENUCONFIG:
+                        # If the previous token is T_(MENU)CONFIG
+                        # ("(menu)config"), we're tokenizing the first line of
+                        # a symbol definition, and should remember this as a
+                        # location where the symbol is defined.
+                        sym.def_locations.append((filename, linenr))
+                    else:
+                        # Otherwise, it's a reference to the symbol
+                        sym.ref_locations.append((filename, linenr))
+
+                    append(sym)
+
+            else:
+                # This restrips whitespace that could have been stripped in the
+                # regex above, but it's worth it since identifiers/keywords are
+                # more common
+                s = s[i:].lstrip()
+                if s == "":
+                    break
+                strlen = len(s)
+                i = 0
+                c = s[0]
+
+                # String literal (constant symbol)
+                if c == '"' or c == "'":
+                    i += 1
+
+                    if "\\" in s:
+                        # Slow path: This could probably be sped up, but it's a
+                        # very unusual case anyway.
+                        quote = c
+                        value = ""
+                        while 1:
+                            if i >= strlen:
+                                _tokenization_error(s, strlen, filename,
+                                                    linenr)
+                            c = s[i]
+                            if c == quote:
+                                break
+                            if c == "\\":
+                                if i + 1 >= strlen:
+                                    _tokenization_error(s, strlen, filename,
+                                                        linenr)
+                                value += s[i + 1]
+                                i += 2
+                            else:
+                                value += c
+                                i += 1
+                        i += 1
+                        append(value)
+                    else:
+                        # Fast path: If the string contains no backslashes (almost
+                        # always) we can simply look for the matching quote.
+                        end = s.find(c, i)
+                        if end == -1:
+                            _tokenization_error(s, strlen, filename, linenr)
+                        append(s[i:end])
+                        i = end + 1
+
+                elif c == "&":
+                    if i + 1 >= strlen:
+                        # Invalid characters are ignored
+                        continue
+                    if s[i + 1] != "&":
+                        # Invalid characters are ignored
+                        i += 1
+                        continue
+                    append(T_AND)
+                    i += 2
+
+                elif c == "|":
+                    if i + 1 >= strlen:
+                        # Invalid characters are ignored
+                        continue
+                    if s[i + 1] != "|":
+                        # Invalid characters are ignored
+                        i += 1
+                        continue
+                    append(T_OR)
+                    i += 2
+
+                elif c == "!":
+                    if i + 1 >= strlen:
+                        _tokenization_error(s, strlen, filename, linenr)
+                    if s[i + 1] == "=":
+                        append(T_UNEQUAL)
+                        i += 2
+                    else:
+                        append(T_NOT)
+                        i += 1
+
+                elif c == "=":
+                    append(T_EQUAL)
+                    i += 1
+
+                elif c == "(":
+                    append(T_OPEN_PAREN)
+                    i += 1
+
+                elif c == ")":
+                    append(T_CLOSE_PAREN)
+                    i += 1
+
+                elif c == "#":
+                    break
+
+                else:
+                    # Invalid characters are ignored
+                    i += 1
+                    continue
+
+            previous = tokens[-1]
+
+        return _Feed(tokens)
+
+    #
+    # Parsing
+    #
+
+    # Expression grammar:
+    #
+    # <expr> -> <symbol>
+    #           <symbol> '=' <symbol>
+    #           <symbol> '!=' <symbol>
+    #           '(' <expr> ')'
+    #           '!' <expr>
+    #           <expr> '&&' <expr>
+    #           <expr> '||' <expr>
+
+    def _parse_expr(self,
+                    feed,
+                    cur_sym_or_choice,
+                    line,
+                    filename = None,
+                    linenr = None,
+                    transform_m = True):
+        """Parse an expression from the tokens in 'feed' using a simple
+        top-down approach. The result has the form (<operator>, <list
+        containing parsed operands>).
+
+        feed -- _Feed instance containing the tokens for the expression.
+
+        cur_sym_or_choice -- The symbol or choice currently being parsed, or
+                             None if we're not parsing a symbol or choice.
+                             Used for recording references to symbols.
+
+        line -- The line containing the expression being parsed.
+
+        filename (default: None) -- The file containing the expression.
+
+        linenr (default: None) -- The line number containing the expression.
+
+        transform_m (default: False) -- Determines if 'm' should be rewritten to
+                                        'm && MODULES' -- see
+                                        parse_val_and_cond()."""
+
+        # Use instance variables to avoid having to pass these as arguments
+        # through the top-down parser in _parse_expr_2(), which is tedious and
+        # obfuscates the code. A profiler run shows no noticeable performance
+        # difference.
+        self.parse_expr_cur_sym_or_choice = cur_sym_or_choice
+        self.parse_expr_line = line
+        self.parse_expr_filename = filename
+        self.parse_expr_linenr = linenr
+        self.parse_expr_transform_m = transform_m
+
+        return self._parse_expr_2(feed)
+
+    def _parse_expr_2(self, feed):
+        or_terms = [self._parse_or_term(feed)]
+        # Keep parsing additional terms while the lookahead is '||'
+        while feed.check(T_OR):
+            or_terms.append(self._parse_or_term(feed))
+
+        return or_terms[0] if len(or_terms) == 1 else (OR, or_terms)
+
+    def _parse_or_term(self, feed):
+        and_terms = [self._parse_factor(feed)]
+        # Keep parsing additional terms while the lookahead is '&&'
+        while feed.check(T_AND):
+            and_terms.append(self._parse_factor(feed))
+
+        return and_terms[0] if len(and_terms) == 1 else (AND, and_terms)
+
+    def _parse_factor(self, feed):
+        if feed.check(T_OPEN_PAREN):
+            expr_parse = self._parse_expr_2(feed)
+
+            if not feed.check(T_CLOSE_PAREN):
+                _parse_error(self.parse_expr_line,
+                             "missing end parenthesis.",
+                             self.parse_expr_filename,
+                             self.parse_expr_linenr)
+
+            return expr_parse
+
+        if feed.check(T_NOT):
+            return (NOT, self._parse_factor(feed))
+
+        sym_or_string = feed.get_next()
+
+        if not isinstance(sym_or_string, (Symbol, str)):
+            _parse_error(self.parse_expr_line,
+                         "malformed expression.",
+                         self.parse_expr_filename,
+                         self.parse_expr_linenr)
+
+        if self.parse_expr_cur_sym_or_choice is not None and \
+           isinstance(sym_or_string, Symbol):
+            self.parse_expr_cur_sym_or_choice.referenced_syms.add(sym_or_string)
+
+        next_token = feed.peek_next()
+
+        # For conditional expressions ('depends on <expr>', '... if <expr>',
+        # etc.), "m" and m are rewritten to "m" && MODULES.
+        if next_token != T_EQUAL and next_token != T_UNEQUAL:
+            if self.parse_expr_transform_m and (sym_or_string is self.m or
+                                                sym_or_string == "m"):
+                return (AND, ["m", self._sym_lookup("MODULES")])
+            return sym_or_string
+
+        relation = EQUAL if (feed.get_next() == T_EQUAL) else UNEQUAL
+        sym_or_string_2 = feed.get_next()
+
+        if self.parse_expr_cur_sym_or_choice is not None and \
+           isinstance(sym_or_string_2, Symbol):
+            self.parse_expr_cur_sym_or_choice.referenced_syms.add(sym_or_string_2)
+
+        if sym_or_string is self.m:
+            sym_or_string = "m"
+
+        if sym_or_string_2 is self.m:
+            sym_or_string_2 = "m"
+
+        return (relation, sym_or_string, sym_or_string_2)
+
+    def _parse_file(self, filename, parent, deps, visible_if_deps, res = None):
+        """Parse the Kconfig file 'filename'. The result is a _Block with all
+        items from the file. See _parse_block() for the meaning of the
+        parameters."""
+        line_feeder = _FileFeed(_get_lines(filename), filename)
+        return self._parse_block(line_feeder, None, parent, deps, visible_if_deps, res)
+
+    def _parse_block(self, line_feeder, end_marker, parent, deps,
+                     visible_if_deps = None, res = None):
+        """Parses a block, which is the contents of either a file or an if,
+        menu, or choice statement. The result is a _Block with the items from
+        the block.
+
+        end_marker -- The token that ends the block, e.g. T_ENDIF ("endif") for
+                      if's. None for files.
+
+        parent -- The enclosing menu, choice or if, or None if we're at the top
+                  level.
+
+        deps -- Dependencies from enclosing menus, choices and if's.
+
+        visible_if_deps (default: None) -- 'visible if' dependencies from
+                        enclosing menus.
+
+        res (default: None) -- The _Block to add items to. If None, a new
+                               _Block is created to hold the items."""
+
+        block = _Block() if res is None else res
+
+        filename = line_feeder.get_filename()
+
+        while 1:
+
+            # Do we already have a tokenized line that we determined wasn't
+            # part of whatever we were parsing earlier? See comment in
+            # Config.__init__().
+            if self.end_line is not None:
+                assert self.end_line_tokens is not None
+                tokens = self.end_line_tokens
+                tokens.go_to_start()
+
+                line = self.end_line
+                linenr = line_feeder.get_linenr()
+
+                self.end_line = None
+                self.end_line_tokens = None
+
+            else:
+                line = line_feeder.get_next()
+                if line is None:
+                    if end_marker is not None:
+                        raise Kconfig_Syntax_Error, (
+                                "Unexpected end of file {0}."
+                                .format(line_feeder.get_filename()))
+                    return block
+
+                linenr = line_feeder.get_linenr()
+
+                tokens = self._tokenize(line, False, filename, linenr)
+
+            if tokens.is_empty():
+                continue
+
+            t0 = tokens.get_next()
+
+            # Have we reached the end of the block?
+            if t0 == end_marker:
+                return block
+
+            if t0 == T_CONFIG or t0 == T_MENUCONFIG:
+                # The tokenizer will automatically allocate a new Symbol object
+                # for any new names it encounters, so we don't need to worry
+                # about that here.
+                sym = tokens.get_next()
+
+                # Symbols defined in multiple places get the parent of their
+                # first definition. However, for symbols whose parents are choice
+                # statements, the choice statement takes precedence.
+                if not sym.is_defined_ or isinstance(parent, Choice):
+                    sym.parent = parent
+
+                sym.is_defined_ = True
+
+                self.kconfig_syms.append(sym)
+                block.add_item(sym)
+
+                self._parse_properties(line_feeder, sym, deps, visible_if_deps)
+
+            elif t0 == T_MENU:
+                menu = Menu()
+                self.menus.append(menu)
+                menu.config = self
+                menu.parent = parent
+                menu.title = tokens.get_next()
+
+                menu.filename = filename
+                menu.linenr = linenr
+
+                # Parse properties and contents
+                self._parse_properties(line_feeder, menu, deps, visible_if_deps)
+                menu.block = self._parse_block(line_feeder,
+                                               T_ENDMENU,
+                                               menu,
+                                               menu.dep_expr,
+                                               _make_and(visible_if_deps,
+                                                         menu.visible_if_expr))
+
+                block.add_item(menu)
+
+            elif t0 == T_IF:
+                # If statements are treated as syntactic sugar for adding
+                # dependencies to enclosed items and do not have an explicit
+                # object representation.
+
+                dep_expr = self._parse_expr(tokens, None, line, filename, linenr)
+                self._parse_block(line_feeder,
+                                  T_ENDIF,
+                                  parent,
+                                  _make_and(dep_expr, deps),
+                                  visible_if_deps,
+                                  block) # Add items to the same block
+
+            elif t0 == T_CHOICE:
+                # We support named choices
+                already_defined = False
+                name = None
+                if len(tokens) > 1 and isinstance(tokens[1], str):
+                    name = tokens[1]
+                    already_defined = name in self.named_choices
+
+                if already_defined:
+                    choice = self.named_choices[name]
+                else:
+                    choice = Choice()
+                    self.choices.append(choice)
+                    if name is not None:
+                        choice.name = name
+                        self.named_choices[name] = choice
+
+                choice.config = self
+                choice.parent = parent
+
+                choice.def_locations.append((filename, linenr))
+
+                # Parse properties and contents
+                self._parse_properties(line_feeder, choice, deps, visible_if_deps)
+                choice.block = self._parse_block(line_feeder,
+                                                 T_ENDCHOICE,
+                                                 choice,
+                                                 None,
+                                                 visible_if_deps)
+
+                choice._determine_actual_symbols()
+
+                # If no type is set for the choice, its type is that of the first
+                # choice item
+                if choice.type == UNKNOWN:
+                    for item in choice.get_symbols():
+                        if item.type != UNKNOWN:
+                            choice.type = item.type
+                            break
+
+                # Each choice item of UNKNOWN type gets the type of the choice
+                for item in choice.get_symbols():
+                    if item.type == UNKNOWN:
+                        item.type = choice.type
+
+                # For named choices defined in multiple locations, only record
+                # at the first definition
+                if not already_defined:
+                    block.add_item(choice)
+
+            elif t0 == T_COMMENT:
+                comment = Comment()
+                comment.config = self
+                comment.parent = parent
+
+                comment.filename = filename
+                comment.linenr = linenr
+
+                comment.text = tokens.get_next()
+                self._parse_properties(line_feeder, comment, deps, visible_if_deps)
+
+                block.add_item(comment)
+                self.comments.append(comment)
+
+            elif t0 == T_SOURCE:
+                kconfig_file = tokens.get_next()
+                exp_kconfig_file = self._expand_sym_refs(kconfig_file)
+                f = os.path.join(self.base_dir, exp_kconfig_file)
+
+                if not os.path.exists(f):
+                    raise IOError, ('{0}:{1}: sourced file "{2}" (expands to\n'
+                                    '"{3}") not found. Perhaps base_dir\n'
+                                    '(argument to Config.__init__(), currently\n'
+                                    '"{4}") is set to the wrong value.'
+                                    .format(filename,
+                                            linenr,
+                                            kconfig_file,
+                                            exp_kconfig_file,
+                                            self.base_dir))
+
+                # Add items to the same block
+                self._parse_file(f, parent, deps, visible_if_deps, block)
+
+            elif t0 == T_MAINMENU:
+                text = tokens.get_next()
+
+                if self.mainmenu_text is not None:
+                    self._warn("overriding 'mainmenu' text. "
+                               'Old value: "{0}", new value: "{1}".'
+                                .format(self.mainmenu_text, text),
+                               filename,
+                               linenr)
+
+                self.mainmenu_text = text
+
+            else:
+                _parse_error(line, "unrecognized construct.", filename, linenr)
+
+    def _parse_properties(self, line_feeder, stmt, deps, visible_if_deps):
+        """Parsing of properties for symbols, menus, choices, and comments."""
+
+        def parse_val_and_cond(tokens, line, filename, linenr):
+            """Parses '<expr1> if <expr2>' constructs, where the 'if' part is
+            optional. Returns a tuple containing the parsed expressions, with
+            None as the second element if the 'if' part is missing."""
+            val = self._parse_expr(tokens, stmt, line, filename, linenr, False)
+
+            if tokens.check(T_IF):
+                return (val, self._parse_expr(tokens, stmt, line, filename, linenr))
+
+            return (val, None)
+
+        # In case the symbol is defined in multiple locations, we need to
+        # remember what prompts, defaults, and selects are new for this
+        # definition, as "depends on" should only apply to the local
+        # definition.
+        new_prompt = None
+        new_def_exprs = []
+        new_selects = []
+
+        # Dependencies from 'depends on' statements
+        depends_on_expr = None
+
+        while 1:
+            line = line_feeder.get_next()
+            if line is None:
+                break
+
+            filename = line_feeder.get_filename()
+            linenr = line_feeder.get_linenr()
+
+            tokens = self._tokenize(line, False, filename, linenr)
+
+            if tokens.is_empty():
+                continue
+
+            t0 = tokens.get_next()
+
+            if t0 == T_HELP:
+                # Find first non-empty line and get its indentation
+
+                line_feeder.remove_while(str.isspace)
+                line = line_feeder.get_next()
+
+                if line is None:
+                    stmt.help = ""
+                    break
+
+                indent = _indentation(line)
+
+                # If the first non-empty lines has zero indent, there is no
+                # help text
+                if indent == 0:
+                    stmt.help = ""
+                    line_feeder.go_back()
+                    break
+
+                help_lines = [_deindent(line, indent)]
+
+                # The help text goes on till the first non-empty line with less
+                # indent
+                while 1:
+                    line = line_feeder.get_next()
+                    if (line is None) or \
+                       (not line.isspace() and _indentation(line) < indent):
+                        stmt.help = "".join(help_lines)
+                        break
+
+                    help_lines.append(_deindent(line, indent))
+
+                if line is None:
+                    break
+
+                line_feeder.go_back()
+
+            elif t0 == T_PROMPT:
+                # 'prompt' properties override each other within a single
+                # definition of a symbol, but additional prompts can be added
+                # by defining the symbol multiple times; hence 'new_prompt'
+                # instead of 'prompt'.
+                new_prompt = parse_val_and_cond(tokens, line, filename, linenr)
+
+            elif t0 == T_DEFAULT:
+                new_def_exprs.append(parse_val_and_cond(tokens, line, filename, linenr))
+
+            elif t0 == T_DEPENDS:
+                if not tokens.check(T_ON):
+                    _parse_error(line, 'expected "on" after "depends".', filename, linenr)
+
+                parsed_deps = self._parse_expr(tokens, stmt, line, filename, linenr)
+
+                if isinstance(stmt, (Menu, Comment)):
+                    stmt.dep_expr = _make_and(stmt.dep_expr, parsed_deps)
+                else:
+                    depends_on_expr = _make_and(depends_on_expr, parsed_deps)
+
+            elif t0 == T_VISIBLE:
+                if not tokens.check(T_IF):
+                    _parse_error(line, 'expected "if" after "visible".', filename, linenr)
+                if not isinstance(stmt, Menu):
+                    _parse_error(line,
+                                 "'visible if' is only valid for menus.",
+                                 filename,
+                                 linenr)
+
+                parsed_deps = self._parse_expr(tokens, stmt, line, filename, linenr)
+                stmt.visible_if_expr = _make_and(stmt.visible_if_expr, parsed_deps)
+
+            elif t0 == T_SELECT:
+                target = tokens.get_next()
+
+                stmt.referenced_syms.add(target)
+                stmt.selected_syms.add(target)
+
+                if tokens.check(T_IF):
+                    new_selects.append((target,
+                                        self._parse_expr(tokens, stmt, line, filename, linenr)))
+                else:
+                    new_selects.append((target, None))
+
+            elif t0 in (T_BOOL, T_TRISTATE, T_INT, T_HEX, T_STRING):
+                stmt.type = token_to_type[t0]
+
+                if len(tokens) > 1:
+                    new_prompt = parse_val_and_cond(tokens, line, filename, linenr)
+
+            elif t0 == T_RANGE:
+                lower = tokens.get_next()
+                upper = tokens.get_next()
+                stmt.referenced_syms.add(lower)
+                stmt.referenced_syms.add(upper)
+
+                if tokens.check(T_IF):
+                    stmt.ranges.append((lower, upper,
+                                        self._parse_expr(tokens, stmt, line, filename, linenr)))
+                else:
+                    stmt.ranges.append((lower, upper, None))
+
+            elif t0 == T_DEF_BOOL:
+                stmt.type = BOOL
+
+                if len(tokens) > 1:
+                    new_def_exprs.append(parse_val_and_cond(tokens, line, filename, linenr))
+
+            elif t0 == T_DEF_TRISTATE:
+                stmt.type = TRISTATE
+
+                if len(tokens) > 1:
+                    new_def_exprs.append(parse_val_and_cond(tokens, line, filename, linenr))
+
+            elif t0 == T_OPTIONAL:
+                if not isinstance(stmt, Choice):
+                    _parse_error(line,
+                                 '"optional" is only valid for choices.',
+                                 filename,
+                                 linenr)
+                stmt.optional = True
+
+            elif t0 == T_OPTION:
+                if tokens.check(T_ENV) and tokens.check(T_EQUAL):
+                    env_var = tokens.get_next()
+
+                    stmt.is_special_ = True
+                    stmt.is_from_env = True
+
+                    if env_var not in os.environ:
+                        self._warn("""
+The symbol {0} references the non-existent environment variable {1} and will
+get the empty string as its value.
+
+If you're using kconfiglib via 'make (i)scriptconfig' it should have set up the
+environment correctly for you. If you still got this message, that might be an
+error, and you should e-mail kconfiglib at gmail.com.
+."""                               .format(stmt.name, env_var),
+                                   filename,
+                                   linenr)
+
+                        stmt.cached_value = ""
+                    else:
+                        stmt.cached_value = os.environ[env_var]
+
+                elif tokens.check(T_DEFCONFIG_LIST):
+                    self.defconfig_sym = stmt
+
+                elif tokens.check(T_MODULES):
+                    self._warn("the 'modules' option is not supported. "
+                               "Let me know if this is a problem for you; "
+                               "it shouldn't be that hard to implement.",
+                               filename,
+                               linenr)
+
+                else:
+                    _parse_error(line, "unrecognized option.", filename, linenr)
+
+            else:
+                # See comment in Config.__init__()
+                self.end_line = line
+                self.end_line_tokens = tokens
+                break
+
+        # Propagate dependencies from enclosing menus and if's.
+
+        # For menus and comments..
+        if isinstance(stmt, (Menu, Comment)):
+            stmt.orig_deps = stmt.dep_expr
+            stmt.deps_from_containing = deps
+            stmt.dep_expr = _make_and(stmt.dep_expr, deps)
+
+            stmt.all_referenced_syms = \
+              stmt.referenced_syms | _get_expr_syms(deps)
+
+        # For symbols and choices..
+        else:
+
+            # See comment for 'menu_dep'
+            stmt.menu_dep = depends_on_expr
+
+            # Propagate dependencies specified with 'depends on' to any new
+            # default expressions, prompts, and selections. ("New" since a
+            # symbol might be defined in multiple places and the dependencies
+            # should only apply to the local definition.)
+
+            new_def_exprs = [(val_expr, _make_and(cond_expr, depends_on_expr))
+                             for (val_expr, cond_expr) in new_def_exprs]
+
+            new_selects = [(target, _make_and(cond_expr, depends_on_expr))
+                           for (target, cond_expr) in new_selects]
+
+            if new_prompt is not None:
+                prompt, cond_expr = new_prompt
+
+                # 'visible if' dependencies from enclosing menus get propagated
+                # to prompts
+                if visible_if_deps is not None:
+                    cond_expr = _make_and(cond_expr, visible_if_deps)
+
+                new_prompt = (prompt, _make_and(cond_expr, depends_on_expr))
+
+            # We save the original expressions -- before any menu and if
+            # conditions have been propagated -- so these can be retrieved
+            # later.
+
+            stmt.orig_def_exprs.extend(new_def_exprs)
+            if new_prompt is not None:
+                stmt.orig_prompts.append(new_prompt)
+
+            # Only symbols can select
+            if isinstance(stmt, Symbol):
+                stmt.orig_selects.extend(new_selects)
+
+            # Save dependencies from enclosing menus and if's
+            stmt.deps_from_containing = deps
+
+            # The set of symbols referenced directly by the symbol/choice plus
+            # all symbols referenced by enclosing menus and if's.
+            stmt.all_referenced_syms = \
+              stmt.referenced_syms | _get_expr_syms(deps)
+
+            # Propagate dependencies from enclosing menus and if's
+
+            stmt.def_exprs.extend([(val_expr, _make_and(cond_expr, deps))
+                                   for (val_expr, cond_expr) in new_def_exprs])
+
+            for (target, cond) in new_selects:
+                target.rev_dep = _make_or(target.rev_dep,
+                                          _make_and(stmt,
+                                                    _make_and(cond, deps)))
+
+            if new_prompt is not None:
+                prompt, cond_expr = new_prompt
+                stmt.prompts.append((prompt, _make_and(cond_expr, deps)))
+
+    #
+    # Symbol table manipulation
+    #
+
+    def _sym_lookup(self, name, add_sym_if_not_exists = True):
+        """Fetches the symbol 'name' from the symbol table, optionally adding
+        it if it does not exist (this is usually what we want)."""
+        if name in self.syms:
+            return self.syms[name]
+
+        new_sym = Symbol()
+        new_sym.config = self
+        new_sym.name = name
+
+        if add_sym_if_not_exists:
+            self.syms[name] = new_sym
+        else:
+            # This warning is generated while evaluating an expression
+            # containing undefined symbols using Config.eval()
+            self._warn("no symbol {0} in configuration".format(name))
+
+        return new_sym
+
+    #
+    # Evaluation of symbols and expressions
+    #
+
+    def _eval_expr(self, expr):
+        """Evaluates an expression and returns one of the tristate values "n",
+        "m" or "y"."""
+        res = self._eval_expr_2(expr)
+
+        # Promote "m" to "y" if we're running without modules. Internally, "m"
+        # is often rewritten to "m" && MODULES by both the C implementation and
+        # kconfiglib, which takes care of cases where "m" should be false if
+        # we're running without modules.
+        if res == "m" and not self._has_modules():
+            return "y"
+
+        return res
+
+    def _eval_expr_2(self, expr):
+        if expr is None:
+            return "y"
+
+        if isinstance(expr, Symbol):
+            # Non-bool/tristate symbols are always "n" in a tristate sense,
+            # regardless of their value
+            if expr.type != BOOL and expr.type != TRISTATE:
+                return "n"
+            return expr.get_value()
+
+        if isinstance(expr, str):
+            return expr if (expr == "y" or expr == "m") else "n"
+
+        first_expr = expr[0]
+
+        if first_expr == OR:
+            res = "n"
+
+            for subexpr in expr[1]:
+                ev = self._eval_expr_2(subexpr)
+
+                # Return immediately upon discovering a "y" term
+                if ev == "y":
+                    return "y"
+
+                if ev == "m":
+                    res = "m"
+
+            # 'res' is either "n" or "m" here; we already handled the
+            # short-circuiting "y" case in the loop.
+            return res
+
+        if first_expr == AND:
+            res = "y"
+
+            for subexpr in expr[1]:
+                ev = self._eval_expr_2(subexpr)
+
+                # Return immediately upon discovering an "n" term
+                if ev == "n":
+                    return "n"
+
+                if ev == "m":
+                    res = "m"
+
+            # 'res' is either "m" or "y" here; we already handled the
+            # short-circuiting "n" case in the loop.
+            return res
+
+        if first_expr == NOT:
+            ev = self._eval_expr_2(expr[1])
+
+            if ev == "y":
+                return "n"
+
+            return "y" if (ev == "n") else "m"
+
+        if first_expr == EQUAL:
+            return "y" if (self._get_str_value(expr[1]) ==
+                           self._get_str_value(expr[2])) else "n"
+
+        if first_expr == UNEQUAL:
+            return "y" if (self._get_str_value(expr[1]) !=
+                           self._get_str_value(expr[2])) else "n"
+
+        _internal_error("Internal error while evaluating expression: "
+                        "unknown operation {0}.".format(first_expr))
+
+    def _get_str_value(self, obj):
+        if isinstance(obj, str):
+            return obj
+        # obj is a Symbol
+        return obj.get_value()
+
+    def _eval_min(self, e1, e2):
+        e1_eval = self._eval_expr(e1)
+        e2_eval = self._eval_expr(e2)
+
+        return e1_eval if tri_less(e1_eval, e2_eval) else e2_eval
+
+    def _eval_max(self, e1, e2):
+        e1_eval = self._eval_expr(e1)
+        e2_eval = self._eval_expr(e2)
+
+        return e1_eval if tri_greater(e1_eval, e2_eval) else e2_eval
+
+    #
+    # Methods related to the MODULES symbol
+    #
+
+    def _has_modules(self):
+        modules_sym = self.syms.get("MODULES")
+        return (modules_sym is not None) and (modules_sym.get_value() == "y")
+
+    #
+    # Dependency tracking
+    #
+
+    def _build_dep(self):
+        """Populates the Symbol.dep sets, linking the symbol to the symbols
+        that immediately depend on it in the sense that changing the value of
+        the symbol might affect the values of those other symbols. This is used
+        for caching/invalidation purposes. The calculated sets might be larger
+        than necessary as we don't do any complicated analysis of the
+        expressions."""
+        for sym in self.syms.itervalues():
+            sym.dep = set()
+
+        # Adds 'sym' as a directly dependent symbol to all symbols that appear
+        # in the expression 'e'
+        def add_expr_deps(e, sym):
+            for s in _get_expr_syms(e):
+                s.dep.add(sym)
+
+        # The directly dependent symbols of a symbol are:
+        #  - Any symbols whose prompts, default values, rev_dep (select
+        #    condition), or ranges depend on the symbol
+        #  - Any symbols that belong to the same choice statement as the symbol
+        #    (these won't be included in 'dep' as that makes the dependency
+        #    graph unwieldy, but Symbol._get_dependent() will include them)
+        #  - Any symbols in a choice statement that depends on the symbol
+        for sym in self.syms.itervalues():
+            for (_, e) in sym.prompts:
+                add_expr_deps(e, sym)
+
+            for (v, e) in sym.def_exprs:
+                add_expr_deps(v, sym)
+                add_expr_deps(e, sym)
+
+            add_expr_deps(sym.rev_dep, sym)
+
+            for (l, u, e) in sym.ranges:
+                add_expr_deps(l, sym)
+                add_expr_deps(u, sym)
+                add_expr_deps(e, sym)
+
+            if sym.is_choice_symbol_:
+                choice = sym.parent
+
+                for (_, e) in choice.prompts:
+                    add_expr_deps(e, sym)
+
+                for (_, e) in choice.def_exprs:
+                    add_expr_deps(e, sym)
+
+    def _expr_val_str(self, expr, no_value_str = "(none)", get_val_instead_of_eval = False):
+        # Since values are valid expressions, _expr_to_str() will get a nice
+        # string representation for those as well.
+
+        if expr is None:
+            return no_value_str
+
+        if get_val_instead_of_eval:
+            if isinstance(expr, str):
+                return _expr_to_str(expr)
+            val = expr.get_value()
+        else:
+            val = self._eval_expr(expr)
+
+        return "{0} (value: {1})".format(_expr_to_str(expr), _expr_to_str(val))
+
+    def _expand_sym_refs(self, s):
+        """Expands $-references to symbols in 's' to symbol values, or to the
+        empty string for undefined symbols."""
+
+        while 1:
+            sym_ref_re_match = sym_ref_re.search(s)
+            if sym_ref_re_match is None:
+                return s
+
+            sym_name = sym_ref_re_match.group(0)[1:]
+            sym = self.syms.get(sym_name)
+            expansion = "" if sym is None else sym.get_value()
+
+            s = s[:sym_ref_re_match.start()] + \
+                expansion + \
+                s[sym_ref_re_match.end():]
+
+    def _get_sym_or_choice_str(self, sc):
+        """Symbols and choices have many properties in common, so we factor out
+        common __str__() stuff here. "sc" is short for "symbol or choice"."""
+
+        # As we deal a lot with string representations here, use some
+        # convenient shorthand:
+        s = _expr_to_str
+
+        #
+        # Common symbol/choice properties
+        #
+
+        user_value_str = "(no user value)" if sc.user_val is None else s(sc.user_val)
+
+        visibility_str = s(sc.get_visibility())
+
+        # Build prompts string
+        if sc.prompts == []:
+            prompts_str = " (no prompts)"
+        else:
+            prompts_str_rows = []
+
+            for (prompt, cond_expr) in sc.orig_prompts:
+                if cond_expr is None:
+                    prompts_str_rows.append(' "{0}"'.format(prompt))
+                else:
+                    prompts_str_rows.append(' "{0}" if '.format(prompt) +
+                                            self._expr_val_str(cond_expr))
+
+            prompts_str = "\n".join(prompts_str_rows)
+
+        # Build locations string
+        if sc.def_locations == []:
+            locations_str = "(no locations)"
+        else:
+            locations_str = " ".join(["{0}:{1}".format(filename, linenr) for
+                                      (filename, linenr) in sc.def_locations])
+
+        # Build additional-dependencies-from-menus-and-if's string
+        additional_deps_str = " " + self._expr_val_str(sc.deps_from_containing,
+                                                       "(no additional dependencies)")
+
+        #
+        # Symbol-specific stuff
+        #
+
+        if isinstance(sc, Symbol):
+
+            # Build value string
+            value_str = s(sc.get_value())
+
+            # Build ranges string
+            if isinstance(sc, Symbol):
+                if sc.ranges == []:
+                    ranges_str = " (no ranges)"
+                else:
+                    ranges_str_rows = []
+
+                    for (l, u, cond_expr) in sc.ranges:
+                        if cond_expr is None:
+                            ranges_str_rows.append(" [{0}, {1}]".format(s(l), s(u)))
+                        else:
+                            ranges_str_rows.append(" [{0}, {1}] if {2}"
+                                                   .format(s(l), s(u), self._expr_val_str(cond_expr)))
+
+                    ranges_str = "\n".join(ranges_str_rows)
+
+            # Build default values string
+            if sc.def_exprs == []:
+                defaults_str = " (no default values)"
+            else:
+                defaults_str_rows = []
+
+                for (val_expr, cond_expr) in sc.orig_def_exprs:
+                    row_str = " " + self._expr_val_str(val_expr, "(none)", sc.type == STRING)
+                    defaults_str_rows.append(row_str)
+                    defaults_str_rows.append("  Condition: " + self._expr_val_str(cond_expr))
+
+                defaults_str = "\n".join(defaults_str_rows)
+
+            # Build selects string
+            if sc.orig_selects == []:
+                selects_str = " (no selects)"
+            else:
+                selects_str_rows = []
+
+                for (target, cond_expr) in sc.orig_selects:
+                    if cond_expr is None:
+                        selects_str_rows.append(" {0}".format(target.name))
+                    else:
+                        selects_str_rows.append(" {0} if ".format(target.name) +
+                                                self._expr_val_str(cond_expr))
+
+                selects_str = "\n".join(selects_str_rows)
+
+            # Build reverse dependencies string
+            if sc.rev_dep == "n":
+                rev_dep_str = " (no reverse dependencies)"
+            else:
+                rev_dep_str = " " + self._expr_val_str(sc.rev_dep)
+
+            res = _sep_lines("Symbol " + (sc.name if sc.name is not None else "(no name)"),
+                             "Type           : " + typename[sc.type],
+                             "Value          : " + value_str,
+                             "User value     : " + user_value_str,
+                             "Visibility     : " + visibility_str,
+                             "Is choice item : " + bool_str[sc.is_choice_symbol_],
+                             "Is defined     : " + bool_str[sc.is_defined_],
+                             "Is from env.   : " + bool_str[sc.is_from_env],
+                             "Is special     : " + bool_str[sc.is_special_] + "\n")
+
+            if sc.ranges != []:
+                res += _sep_lines("Ranges:",
+                                  ranges_str + "\n")
+
+            res += _sep_lines("Prompts:",
+                              prompts_str,
+                              "Default values:",
+                              defaults_str,
+                              "Selects:",
+                              selects_str,
+                              "Reverse dependencies:",
+                              rev_dep_str,
+                              "Additional dependencies from enclosing menus and if's:",
+                              additional_deps_str,
+                              "Locations: " + locations_str)
+
+            return res
+
+        #
+        # Choice-specific stuff
+        #
+
+        # Build name string (for named choices)
+        if sc.name is None:
+            name_str = "(no name)"
+        else:
+            name_str = sc.name
+
+        # Build selected symbol string
+        sel = sc.get_selection()
+        if sel is None:
+            sel_str = "(no selection)"
+        else:
+            sel_str = sel.name
+
+        # Build mode string
+        mode_str = s(sc.get_mode())
+
+        # Build default values string
+        if sc.def_exprs == []:
+            defaults_str = " (no default values)"
+        else:
+            defaults_str_rows = []
+
+            for (sym, cond_expr) in sc.orig_def_exprs:
+                if cond_expr is None:
+                    defaults_str_rows.append(" {0}".format(sym.name))
+                else:
+                    defaults_str_rows.append(" {0} if ".format(sym.name) +
+                                             self._expr_val_str(cond_expr))
+
+            defaults_str = "\n".join(defaults_str_rows)
+
+        # Build contained symbols string
+        names = [sym.name for sym in sc.get_symbols()]
+
+        if names == []:
+            syms_string = "(empty)"
+        else:
+            syms_string = " ".join(names)
+
+        return _sep_lines("Choice",
+                          "Name (for named choices): " + name_str,
+                          "Type            : " + typename[sc.type],
+                          "Selected symbol : " + sel_str,
+                          "User value      : " + user_value_str,
+                          "Mode            : " + mode_str,
+                          "Visibility      : " + visibility_str,
+                          "Optional        : " + bool_str[sc.optional],
+                          "Prompts:",
+                          prompts_str,
+                          "Defaults:",
+                          defaults_str,
+                          "Choice symbols:",
+                          " " + syms_string,
+                          "Additional dependencies from enclosing menus and if's:",
+                          additional_deps_str,
+                          "Locations: " + locations_str)
+
+    def _expr_depends_on(self, expr, sym):
+        """Reimplementation of expr_depends_symbol() from mconf.c. Used to
+        determine if a submenu should be implicitly created, which influences what
+        items inside choice statements are considered choice items."""
+        if expr is None:
+            return False
+
+        def rec(expr):
+            if isinstance(expr, str):
+                return False
+
+            if isinstance(expr, Symbol):
+                return expr is sym
+
+            e0 = expr[0]
+
+            if e0 == EQUAL or e0 == UNEQUAL:
+                return self._eq_to_sym(expr) is sym
+
+            if e0 == AND:
+                for and_expr in expr[1]:
+                    if rec(and_expr):
+                        return True
+
+            return False
+
+        return rec(expr)
+
+    def _eq_to_sym(self, eq):
+        """_expr_depends_on() helper. For (in)equalities of the form sym = y/m
+        or sym != n, returns sym. For other (in)equalities, returns None."""
+        relation, left, right = eq
+
+        left  = self._transform_n_m_y(left)
+        right = self._transform_n_m_y(right)
+
+        # Make sure the symbol (if any) appears to the left
+        if not isinstance(left, Symbol):
+            left, right = right, left
+
+        if not isinstance(left, Symbol):
+            return None
+
+        if (relation == EQUAL   and (right == "m" or right == "y")) or \
+           (relation == UNEQUAL and right == "n"):
+            return left
+
+        return None
+
+    def _transform_n_m_y(self, item):
+        """_eq_to_sym() helper. Translates the symbols n, m, and y to their
+        string equivalents."""
+        if item is self.n:
+            return "n"
+        if item is self.m:
+            return "m"
+        if item is self.y:
+            return "y"
+        return item
+
+    def _warn(self, msg, filename = None, linenr = None):
+        """For printing warnings to stderr."""
+        if self.print_warnings:
+            self._warn_or_undef_assign(msg, WARNING, filename, linenr)
+
+    def _undef_assign(self, msg, filename = None, linenr = None):
+        """For printing informational messages related to assignments
+        to undefined variables to stderr."""
+        if self.print_undef_assign:
+            self._warn_or_undef_assign(msg, UNDEF_ASSIGN, filename, linenr)
+
+    def _warn_or_undef_assign(self, msg, msg_type, filename, linenr):
+        if filename is not None:
+            sys.stderr.write("{0}:".format(_clean_up_path(filename)))
+        if linenr is not None:
+            sys.stderr.write("{0}:".format(linenr))
+
+        if msg_type == WARNING:
+            sys.stderr.write("warning: ")
+        elif msg_type == UNDEF_ASSIGN:
+            sys.stderr.write("info: ")
+        else:
+            _internal_error('Internal error while printing warning: unknown warning type "{0}".'
+                            .format(msg_type))
+
+        sys.stderr.write(msg + "\n")
+
+def _get_expr_syms(expr):
+    """Returns the set() of symbols appearing in expr."""
+    res = set()
+    if expr is None:
+        return res
+
+    def rec(expr):
+        if isinstance(expr, Symbol):
+            res.add(expr)
+            return
+
+        if isinstance(expr, str):
+            return
+
+        e0 = expr[0]
+
+        if e0 == OR or e0 == AND:
+            for term in expr[1]:
+                rec(term)
+
+        elif e0 == NOT:
+            rec(expr[1])
+
+        elif e0 == EQUAL or e0 == UNEQUAL:
+            _, v1, v2 = expr
+
+            if isinstance(v1, Symbol):
+                res.add(v1)
+
+            if isinstance(v2, Symbol):
+                res.add(v2)
+
+        else:
+            _internal_error("Internal error while fetching symbols from an "
+                            "expression with token stream {0}.".format(expr))
+
+    rec(expr)
+    return res
+
+
+#
+# Construction of expressions
+#
+
+# These functions as well as the _eval_min/max() functions above equate
+# None with "y", which is usually what we want, but needs to be kept in
+# mind.
+
+def _make_or(e1, e2):
+    # Perform trivial simplification and avoid None's (which
+    # correspond to y's)
+    if e1 is None or e2 is None or \
+       e1 == "y" or e2 == "y":
+        return "y"
+
+    if e1 == "n":
+        return e2
+
+    if e2 == "n":
+        return e1
+
+    # Prefer to merge/update argument list if possible instead of creating
+    # a new OR node
+
+    if isinstance(e1, tuple) and e1[0] == OR:
+        if isinstance(e2, tuple) and e2[0] == OR:
+            return (OR, e1[1] + e2[1])
+        return (OR, e1[1] + [e2])
+
+    if isinstance(e2, tuple) and e2[0] == OR:
+        return (OR, e2[1] + [e1])
+
+    return (OR, [e1, e2])
+
+# Note: returns None if e1 == e2 == None
+
+def _make_and(e1, e2):
+    if e1 == "n" or e2 == "n":
+        return "n"
+
+    if e1 is None or e1 == "y":
+        return e2
+
+    if e2 is None or e2 == "y":
+        return e1
+
+    # Prefer to merge/update argument list if possible instead of creating
+    # a new AND node
+
+    if isinstance(e1, tuple) and e1[0] == AND:
+        if isinstance(e2, tuple) and e2[0] == AND:
+            return (AND, e1[1] + e2[1])
+        return (AND, e1[1] + [e2])
+
+    if isinstance(e2, tuple) and e2[0] == AND:
+        return (AND, e2[1] + [e1])
+
+    return (AND, [e1, e2])
+
+#
+# Constants and functions related to types, parsing, evaluation and printing,
+# put globally to unclutter the Config class a bit.
+#
+
+# Tokens
+(T_OR, T_AND, T_NOT,
+ T_OPEN_PAREN, T_CLOSE_PAREN,
+ T_EQUAL, T_UNEQUAL,
+ T_MAINMENU, T_MENU, T_ENDMENU,
+ T_SOURCE, T_CHOICE, T_ENDCHOICE,
+ T_COMMENT, T_CONFIG, T_MENUCONFIG,
+ T_HELP, T_IF, T_ENDIF, T_DEPENDS, T_ON,
+ T_OPTIONAL, T_PROMPT, T_DEFAULT,
+ T_BOOL, T_TRISTATE, T_HEX, T_INT, T_STRING,
+ T_DEF_BOOL, T_DEF_TRISTATE,
+ T_SELECT, T_RANGE, T_OPTION, T_ENV,
+ T_DEFCONFIG_LIST, T_MODULES, T_VISIBLE) = range(0, 38)
+
+# Keyword to token map
+keywords = {
+        "mainmenu"       : T_MAINMENU,
+        "menu"           : T_MENU,
+        "endmenu"        : T_ENDMENU,
+        "endif"          : T_ENDIF,
+        "endchoice"      : T_ENDCHOICE,
+        "source"         : T_SOURCE,
+        "choice"         : T_CHOICE,
+        "config"         : T_CONFIG,
+        "comment"        : T_COMMENT,
+        "menuconfig"     : T_MENUCONFIG,
+        "help"           : T_HELP,
+        "if"             : T_IF,
+        "depends"        : T_DEPENDS,
+        "on"             : T_ON,
+        "optional"       : T_OPTIONAL,
+        "prompt"         : T_PROMPT,
+        "default"        : T_DEFAULT,
+        "bool"           : T_BOOL,
+        "boolean"        : T_BOOL,
+        "tristate"       : T_TRISTATE,
+        "int"            : T_INT,
+        "hex"            : T_HEX,
+        "def_bool"       : T_DEF_BOOL,
+        "def_tristate"   : T_DEF_TRISTATE,
+        "string"         : T_STRING,
+        "select"         : T_SELECT,
+        "range"          : T_RANGE,
+        "option"         : T_OPTION,
+        "env"            : T_ENV,
+        "defconfig_list" : T_DEFCONFIG_LIST,
+        "modules"        : T_MODULES,
+        "visible"        : T_VISIBLE }
+
+# Strings to use for True and False
+bool_str = { False : "false", True : "true" }
+
+# Tokens after which identifier-like lexemes are treated as strings. T_CHOICE
+# is included to avoid symbols being registered for named choices.
+string_lex = frozenset((T_BOOL, T_TRISTATE, T_INT, T_HEX, T_STRING, T_CHOICE,
+                        T_PROMPT, T_MENU, T_COMMENT, T_SOURCE, T_MAINMENU))
+
+# Matches the initial token on a line; see _tokenize().
+initial_token_re = re.compile(r"[^\w]*(\w+)")
+
+# Matches an identifier/keyword optionally preceded by whitespace
+id_keyword_re = re.compile(r"\s*([\w./-]+)")
+
+# Regular expressions for parsing .config files
+set_re   = re.compile(r"CONFIG_(\w+)=(.*)")
+unset_re = re.compile(r"# CONFIG_(\w+) is not set")
+
+# Regular expression for finding $-references to symbols in strings
+sym_ref_re = re.compile(r"\$[A-Za-z_]+")
+
+# Integers representing symbol types
+UNKNOWN, BOOL, TRISTATE, STRING, HEX, INT = range(0, 6)
+
+# Strings to use for types
+typename = {
+        UNKNOWN  : "unknown",
+        BOOL     : "bool",
+        TRISTATE : "tristate",
+        STRING   : "string",
+        HEX      : "hex",
+        INT      : "int" }
+
+# Token to type mapping
+token_to_type = { T_BOOL     : BOOL,
+                  T_TRISTATE : TRISTATE,
+                  T_STRING   : STRING,
+                  T_INT      : INT,
+                  T_HEX      : HEX }
+
+# Default values for symbols of different types (the value the symbol gets if
+# it is not assigned a user value and none of its 'default' clauses kick in)
+default_value = { BOOL     : "n",
+                  TRISTATE : "n",
+                  STRING   : "",
+                  INT      : "",
+                  HEX      : "" }
+
+# Indicates that no item is selected in a choice statement
+NO_SELECTION = 0
+
+# Integers representing expression types
+OR, AND, NOT, EQUAL, UNEQUAL = range(0, 5)
+
+# Map from tristate values to integers
+tri_to_int = { "n" : 0, "m" : 1, "y" : 2 }
+
+# Printing-related stuff
+
+op_to_str = { AND     : " && ",
+              OR      : " || ",
+              EQUAL   : " = ",
+              UNEQUAL : " != " }
+
+precedence = { OR : 0, AND : 1, NOT : 2 }
+
+# Types of informational messages
+WARNING = 0
+UNDEF_ASSIGN = 1
+
+def _intersperse(lst, op):
+    """_expr_to_str() helper. Gets the string representation of each expression in lst
+    and produces a list where op has been inserted between the elements."""
+    if lst == []:
+        return ""
+
+    res = []
+
+    def handle_sub_expr(expr):
+        no_parens = isinstance(expr, (str, Symbol)) or \
+                    expr[0] in (EQUAL, UNEQUAL) or \
+                    precedence[op] <= precedence[expr[0]]
+        if not no_parens:
+            res.append("(")
+        res.extend(_expr_to_str_rec(expr))
+        if not no_parens:
+            res.append(")")
+
+    op_str = op_to_str[op]
+
+    handle_sub_expr(lst[0])
+    for expr in lst[1:]:
+        res.append(op_str)
+        handle_sub_expr(expr)
+
+    return res
+
+def _expr_to_str(expr):
+    s = "".join(_expr_to_str_rec(expr))
+    return s
+
+def _sym_str_string(sym_or_str):
+    if isinstance(sym_or_str, str):
+        return '"{0}"'.format(sym_or_str)
+    return sym_or_str.name
+
+def _expr_to_str_rec(expr):
+    if expr is None:
+        return [""]
+
+    if isinstance(expr, (Symbol, str)):
+        return [_sym_str_string(expr)]
+
+    e0 = expr[0]
+
+    if e0 == OR or e0 == AND:
+        return _intersperse(expr[1], expr[0])
+
+    if e0 == NOT:
+        need_parens = not isinstance(expr[1], (str, Symbol))
+
+        res = ["!"]
+        if need_parens:
+            res.append("(")
+        res.extend(_expr_to_str_rec(expr[1]))
+        if need_parens:
+            res.append(")")
+        return res
+
+    if e0 == EQUAL or e0 == UNEQUAL:
+        return [_sym_str_string(expr[1]),
+                op_to_str[expr[0]],
+                _sym_str_string(expr[2])]
+
+class _Block:
+
+    """Represents a list of items (symbols, menus, choice statements and
+    comments) appearing at the top-level of a file or witin a menu, choice or
+    if statement."""
+
+    def __init__(self):
+        self.items = []
+
+    def get_items(self):
+        return self.items
+
+    def add_item(self, item):
+        self.items.append(item)
+
+    def _make_conf(self):
+        # Collect the substrings in a list and later use join() instead of +=
+        # to build the final .config contents. With older Python versions, this
+        # yields linear instead of quadratic complexity.
+        strings = []
+        for item in self.items:
+            strings.extend(item._make_conf())
+
+        return strings
+
+    def add_depend_expr(self, expr):
+        for item in self.items:
+            item.add_depend_expr(expr)
+
+class Item():
+
+    """Base class for symbols and other Kconfig constructs. Subclasses are
+    Symbol, Choice, Menu, and Comment."""
+
+    def is_symbol(self):
+        """Returns True if the item is a symbol, otherwise False. Short for
+        isinstance(item, kconfiglib.Symbol)."""
+        return isinstance(self, Symbol)
+
+    def is_choice(self):
+        """Returns True if the item is a choice, otherwise False. Short for
+        isinstance(item, kconfiglib.Choice)."""
+        return isinstance(self, Choice)
+
+    def is_menu(self):
+        """Returns True if the item is a menu, otherwise False. Short for
+        isinstance(item, kconfiglib.Menu)."""
+        return isinstance(self, Menu)
+
+    def is_comment(self):
+        """Returns True if the item is a comment, otherwise False. Short for
+        isinstance(item, kconfiglib.Comment)."""
+        return isinstance(self, Comment)
+
+class _HasVisibility():
+
+    """Base class for elements that have a "visibility" that acts as an upper
+    limit on the values a user can set for them. Subclasses are Symbol and
+    Choice (which supply some of the attributes)."""
+
+    def __init__(self):
+        self.cached_visibility = None
+        self.prompts = []
+
+    def _invalidate(self):
+        self.cached_visibility = None
+
+    def _get_visibility(self):
+        if self.cached_visibility is None:
+            vis = "n"
+            for (prompt, cond_expr) in self.prompts:
+                vis = self.config._eval_max(vis, cond_expr)
+
+            if isinstance(self, Symbol) and self.is_choice_symbol_:
+                vis = self.config._eval_min(vis, self.parent._get_visibility())
+
+            # Promote "m" to "y" if we're dealing with a non-tristate
+            if vis == "m" and self.type != TRISTATE:
+                vis = "y"
+
+            self.cached_visibility = vis
+
+        return self.cached_visibility
+
+class Symbol(Item, _HasVisibility):
+
+    """Represents a configuration symbol - e.g. FOO for
+
+    config FOO
+        ..."""
+
+    #
+    # Public interface
+    #
+
+    def get_value(self):
+        """Calculate and return the value of the symbol. See also
+        Symbol.set_user_value()."""
+
+        if self.cached_value is not None:
+            return self.cached_value
+
+        self.write_to_conf = False
+
+        # As a quirk of Kconfig, undefined symbols get their name as their
+        # value. This is why things like "FOO = bar" work for seeing if FOO has
+        # the value "bar".
+        if self.type == UNKNOWN:
+            self.cached_value = self.name
+            return self.name
+
+        new_val = default_value[self.type]
+
+        vis = self._get_visibility()
+
+        if self.type == BOOL or self.type == TRISTATE:
+            # The visibility and mode (modules-only or single-selection) of
+            # choice items will be taken into account in self._get_visibility()
+
+            if self.is_choice_symbol_:
+                if vis != "n":
+                    choice = self.parent
+                    mode = choice.get_mode()
+
+                    self.write_to_conf = (mode != "n")
+
+                    if mode == "y":
+                        new_val = "y" if (choice.get_selection() is self) else "n"
+                    elif mode == "m":
+                        if self.user_val == "m" or self.user_val == "y":
+                            new_val = "m"
+
+            else:
+                use_defaults = True
+
+                if vis != "n":
+                    # If the symbol is visible and has a user value, use that.
+                    # Otherwise, look@defaults.
+                    self.write_to_conf = True
+
+                    if self.user_val is not None:
+                        new_val = self.config._eval_min(self.user_val, vis)
+                        use_defaults = False
+
+                if use_defaults:
+                    for (val_expr, cond_expr) in self.def_exprs:
+                        cond_eval = self.config._eval_expr(cond_expr)
+
+                        if cond_eval != "n":
+                            self.write_to_conf = True
+                            new_val = self.config._eval_min(val_expr, cond_eval)
+                            break
+
+                # Reverse dependencies take precedence
+                rev_dep_val = self.config._eval_expr(self.rev_dep)
+
+                if rev_dep_val != "n":
+                    self.write_to_conf = True
+                    new_val = self.config._eval_max(new_val, rev_dep_val)
+
+            # Promote "m" to "y" for booleans
+            if new_val == "m" and self.type == BOOL:
+                new_val = "y"
+
+        elif self.type == STRING:
+            use_defaults = True
+
+            if vis != "n":
+                self.write_to_conf = True
+                if self.user_val is not None:
+                    new_val = self.user_val
+                    use_defaults = False
+
+            if use_defaults:
+                for (val_expr, cond_expr) in self.def_exprs:
+                    if self.config._eval_expr(cond_expr) != "n":
+                        self.write_to_conf = True
+                        new_val = self.config._get_str_value(val_expr)
+                        break
+
+        elif self.type == HEX or self.type == INT:
+            has_active_range = False
+            low = None
+            high = None
+            use_defaults = True
+
+            base = 16 if self.type == HEX else 10
+
+            for(l, h, cond_expr) in self.ranges:
+                if self.config._eval_expr(cond_expr) != "n":
+                    has_active_range = True
+
+                    low_str = self.config._get_str_value(l)
+                    high_str = self.config._get_str_value(h)
+
+                    low = int(low_str, base) if \
+                      _is_base_n(low_str, base) else 0
+                    high = int(high_str, base) if \
+                      _is_base_n(high_str, base) else 0
+
+                    break
+
+            if vis != "n":
+                self.write_to_conf = True
+
+                if self.user_val is not None and \
+                   _is_base_n(self.user_val, base) and \
+                   (not has_active_range or
+                    low <= int(self.user_val, base) <= high):
+
+                    # If the user value is OK, it is stored in exactly the same
+                    # form as specified in the assignment (with or without
+                    # "0x", etc).
+
+                    use_defaults = False
+                    new_val = self.user_val
+
+            if use_defaults:
+                for (val_expr, cond_expr) in self.def_exprs:
+                    if self.config._eval_expr(cond_expr) != "n":
+                        self.write_to_conf = True
+
+                        # If the default value is OK, it is stored in exactly
+                        # the same form as specified. Otherwise, it is clamped
+                        # to the range, and the output has "0x" as appropriate
+                        # for the type.
+
+                        new_val = self.config._get_str_value(val_expr)
+
+                        if _is_base_n(new_val, base):
+                            new_val_num = int(new_val, base)
+                            if has_active_range:
+                                clamped_val = None
+
+                                if new_val_num < low:
+                                    clamped_val = low
+                                elif new_val_num > high:
+                                    clamped_val = high
+
+                                if clamped_val is not None:
+                                    new_val = (hex(clamped_val) if \
+                                      self.type == HEX else str(clamped_val))
+
+                            break
+                else: # For the for loop
+                    # If no user value or default kicks in but the hex/int has
+                    # an active range, then the low end of the range is used,
+                    # provided it's > 0, with "0x" prepended as appropriate.
+
+                    if has_active_range and low > 0:
+                        new_val = (hex(low) if self.type == HEX else str(low))
+
+        self.cached_value = new_val
+        return new_val
+
+    def set_user_value(self, v):
+        """Sets the user value of the symbol.
+
+        Equal in effect to assigning the value to the symbol within a .config
+        file. Use get_lower/upper_bound() or get_assignable_values() to find
+        the range of currently assignable values for bool and tristate symbols;
+        setting values outside this range will cause the user value to differ
+        from the result of Symbol.get_value() (be truncated). Values that are
+        invalid for the type (such as a_bool.set_user_value("foo")) are
+        ignored, and a warning is emitted if an attempt is made to assign such
+        a value.
+
+        For any type of symbol, is_modifiable() can be used to check if a user
+        value will currently have any effect on the symbol, as determined by
+        its visibility and range of assignable values. Any value that is valid
+        for the type (bool, tristate, etc.) will end up being reflected in
+        get_user_value() though, and might have an effect later if conditions
+        change. To get rid of the user value, use unset_user_value().
+
+        Any symbols dependent on the symbol are (recursively) invalidated, so
+        things will just work with regards to dependencies.
+
+        v -- The user value to give to the symbol."""
+        self._set_user_value_no_invalidate(v, False)
+
+        # There might be something more efficient you could do here, but play
+        # it safe.
+        if self.name == "MODULES":
+            self.config._invalidate_all()
+            return
+
+        self._invalidate()
+        self._invalidate_dependent()
+
+    def unset_user_value(self):
+        """Resets the user value of the symbol, as if the symbol had never
+        gotten a user value via Config.load_config() or
+        Symbol.set_user_value()."""
+        self._unset_user_value_no_recursive_invalidate()
+        self._invalidate_dependent()
+
+    def get_user_value(self):
+        """Returns the value assigned to the symbol in a .config or via
+        Symbol.set_user_value() (provided the value was valid for the type of the
+        symbol). Returns None in case of no user value."""
+        return self.user_val
+
+    def get_name(self):
+        """Returns the name of the symbol."""
+        return self.name
+
+    def get_upper_bound(self):
+        """For string/hex/int symbols and for bool and tristate symbols that
+        cannot be modified (see is_modifiable()), returns None.
+
+        Otherwise, returns the highest value the symbol can be set to with
+        Symbol.set_user_value() (that will not be truncated): one of "m" or "y",
+        arranged from lowest to highest. This corresponds to the highest value
+        the symbol could be given in e.g. the 'make menuconfig' interface.
+
+        See also the tri_less*() and tri_greater*() functions, which could come
+        in handy."""
+        if self.type != BOOL and self.type != TRISTATE:
+            return None
+        rev_dep = self.config._eval_expr(self.rev_dep)
+        # A bool selected to "m" gets promoted to "y"
+        if self.type == BOOL and rev_dep == "m":
+            rev_dep = "y"
+        vis = self._get_visibility()
+        if (tri_to_int[vis] - tri_to_int[rev_dep]) > 0:
+            return vis
+        return None
+
+    def get_lower_bound(self):
+        """For string/hex/int symbols and for bool and tristate symbols that
+        cannot be modified (see is_modifiable()), returns None.
+
+        Otherwise, returns the lowest value the symbol can be set to with
+        Symbol.set_user_value() (that will not be truncated): one of "n" or "m",
+        arranged from lowest to highest. This corresponds to the lowest value
+        the symbol could be given in e.g. the 'make menuconfig' interface.
+
+        See also the tri_less*() and tri_greater*() functions, which could come
+        in handy."""
+        if self.type != BOOL and self.type != TRISTATE:
+            return None
+        rev_dep = self.config._eval_expr(self.rev_dep)
+        # A bool selected to "m" gets promoted to "y"
+        if self.type == BOOL and rev_dep == "m":
+            rev_dep = "y"
+        if (tri_to_int[self._get_visibility()] - tri_to_int[rev_dep]) > 0:
+            return rev_dep
+        return None
+
+    def get_assignable_values(self):
+        """For string/hex/int symbols and for bool and tristate symbols that
+        cannot be modified (see is_modifiable()), returns the empty list.
+
+        Otherwise, returns a list containing the user values that can be
+        assigned to the symbol (that won't be truncated). Usage example:
+
+        if "m" in sym.get_assignable_values():
+            sym.set_user_value("m")
+
+        This is basically a more convenient interface to
+        get_lower/upper_bound() when wanting to test if a particular tristate
+        value can be assigned."""
+        if self.type != BOOL and self.type != TRISTATE:
+            return []
+        rev_dep = self.config._eval_expr(self.rev_dep)
+        # A bool selected to "m" gets promoted to "y"
+        if self.type == BOOL and rev_dep == "m":
+            rev_dep = "y"
+        res = ["n", "m", "y"][tri_to_int[rev_dep] :
+                              tri_to_int[self._get_visibility()] + 1]
+        return res if len(res) > 1 else []
+
+    def get_type(self):
+        """Returns the type of the symbol: one of UNKNOWN, BOOL, TRISTATE,
+        STRING, HEX, or INT. These are defined at the top level of the module,
+        so you'd do something like
+
+        if sym.get_type() == kconfiglib.STRING:
+            ..."""
+        return self.type
+
+    def get_visibility(self):
+        """Returns the visibility of the symbol: one of "n", "m" or "y". For
+        bool and tristate symbols, this is an upper bound on the value users
+        can set for the symbol. For other types of symbols, a visibility of "n"
+        means the user value will be ignored. A visibility of "n" corresponds
+        to not being visible in the 'make *config' interfaces.
+
+        Example (assuming we're running with modules enabled -- i.e., MODULES
+        set to 'y'):
+
+        # Assume this has been assigned 'n'
+        config N_SYM
+            tristate "N_SYM"
+
+        # Assume this has been assigned 'm'
+        config M_SYM
+            tristate "M_SYM"
+
+        # Has visibility 'n'
+        config A
+            tristate "A"
+            depends on N_SYM
+
+        # Has visibility 'm'
+        config B
+            tristate "B"
+            depends on M_SYM
+
+        # Has visibility 'y'
+        config C
+            tristate "C"
+
+        # Has no prompt, and hence visibility 'n'
+        config D
+            tristate
+
+        Having visibility be tri-valued ensures that e.g. a symbol cannot be
+        set to "y" by the user if it depends on a symbol with value "m", which
+        wouldn't be safe.
+
+        You should probably look at get_lower/upper_bound(),
+        get_assignable_values() and is_modifiable() before using this."""
+        return self._get_visibility()
+
+    def get_parent(self):
+        """Returns the menu or choice statement that contains the symbol, or
+        None if the symbol is at the top level. Note that if statements are
+        treated as syntactic and do not have an explicit class
+        representation."""
+        return self.parent
+
+    def get_referenced_symbols(self, refs_from_enclosing = False):
+        """Returns the set() of all symbols referenced by this symbol. For
+        example, the symbol defined by
+
+        config FOO
+            bool
+            prompt "foo" if A && B
+            default C if D
+            depends on E
+            select F if G
+
+        references the symbols A through G.
+
+        refs_from_enclosing (default: False) -- If True, the symbols
+                            referenced by enclosing menus and if's will be
+                            included in the result."""
+        return self.all_referenced_syms if refs_from_enclosing else self.referenced_syms
+
+    def get_selected_symbols(self):
+        """Returns the set() of all symbols X for which this symbol has a
+        'select X' or 'select X if Y' (regardless of whether Y is satisfied or
+        not). This is a subset of the symbols returned by
+        get_referenced_symbols()."""
+        return self.selected_syms
+
+    def get_help(self):
+        """Returns the help text of the symbol, or None if the symbol has no
+        help text."""
+        return self.help
+
+    def get_config(self):
+        """Returns the Config instance this symbol is from."""
+        return self.config
+
+    def get_def_locations(self):
+        """Returns a list of (filename, linenr) tuples, where filename (string)
+        and linenr (int) represent a location where the symbol is defined. For
+        the vast majority of symbols this list will only contain one element.
+        For the following Kconfig, FOO would get two entries: the lines marked
+        with *.
+
+        config FOO *
+            bool "foo prompt 1"
+
+        config FOO *
+            bool "foo prompt 2"
+        """
+        return self.def_locations
+
+    def get_ref_locations(self):
+        """Returns a list of (filename, linenr) tuples, where filename (string)
+        and linenr (int) represent a location where the symbol is referenced in
+        the configuration. For example, the lines marked by * would be included
+        for FOO below:
+
+        config A
+            bool
+            default BAR || FOO *
+
+        config B
+            tristate
+            depends on FOO *
+            default m if FOO *
+
+        if FOO *
+            config A
+                bool "A"
+        endif
+
+        config FOO (definition not included)
+            bool
+        """
+        return self.ref_locations
+
+    def is_modifiable(self):
+        """Returns True if the value of the symbol could be modified by calling
+        Symbol.set_user_value() and False otherwise.
+
+        For bools and tristates, this corresponds to the symbol being visible
+        in the 'make menuconfig' interface and not already being pinned to a
+        specific value (e.g. because it is selected by another symbol).
+
+        For strings and numbers, this corresponds to just being visible. (See
+        Symbol.get_visibility().)"""
+        if self.is_special_:
+            return False
+        if self.type == BOOL or self.type == TRISTATE:
+            rev_dep = self.config._eval_expr(self.rev_dep)
+            # A bool selected to "m" gets promoted to "y"
+            if self.type == BOOL and rev_dep == "m":
+                rev_dep = "y"
+            return (tri_to_int[self._get_visibility()] -
+                    tri_to_int[rev_dep]) > 0
+        return self._get_visibility() != "n"
+
+    def is_defined(self):
+        """Returns False if the symbol is referred to in the Kconfig but never
+        actually defined, otherwise True."""
+        return self.is_defined_
+
+    def is_special(self):
+        """Returns True if the symbol is one of the special symbols n, m, y, or
+        UNAME_RELEASE, or gets its value from the environment. Otherwise,
+        returns False."""
+        return self.is_special_
+
+    def is_from_environment(self):
+        """Returns True if the symbol gets its value from the environment.
+        Otherwise, returns False."""
+        return self.is_from_env
+
+    def has_ranges(self):
+        """Returns True if the symbol is of type INT or HEX and has ranges that
+        limits what values it can take on, otherwise False."""
+        return self.ranges != []
+
+    def is_choice_symbol(self):
+        """Returns True if the symbol is in a choice statement and is an actual
+        choice symbol (see Choice.get_symbols()); otherwise, returns
+        False."""
+        return self.is_choice_symbol_
+
+    def is_choice_selection(self):
+        """Returns True if the symbol is contained in a choice statement and is
+        the selected item, otherwise False. Equivalent to 'sym.is_choice_symbol()
+        and sym.get_parent().get_selection() is sym'."""
+        return self.is_choice_symbol_ and self.parent.get_selection() is self
+
+    def __str__(self):
+        """Returns a string containing various information about the symbol."""
+        return self.config._get_sym_or_choice_str(self)
+
+    #
+    # Private methods
+    #
+
+    def __init__(self):
+        """Symbol constructor -- not intended to be called directly by
+        kconfiglib clients."""
+
+        # Set default values
+        _HasVisibility.__init__(self)
+
+        self.config = None
+
+        self.parent = None
+        self.name = None
+        self.type = UNKNOWN
+
+        self.def_exprs = []
+        self.ranges = []
+        self.rev_dep = "n"
+
+        # The prompt, default value and select conditions without any
+        # dependencies from menus or if's propagated to them
+
+        self.orig_prompts = []
+        self.orig_def_exprs = []
+        self.orig_selects = []
+
+        # Dependencies inherited from containing menus and if's
+        self.deps_from_containing = None
+
+        self.help = None
+
+        # The set of symbols referenced by this symbol (see
+        # get_referenced_symbols())
+        self.referenced_syms = set()
+
+        # The set of symbols selected by this symbol (see
+        # get_selected_symbols())
+        self.selected_syms = set()
+
+        # Like 'referenced_syms', but includes symbols from
+        # dependencies inherited from enclosing menus and if's
+        self.all_referenced_syms = set()
+
+        # This is set to True for "actual" choice symbols. See
+        # Choice._determine_actual_symbols(). The trailing underscore avoids a
+        # collision with is_choice_symbol().
+        self.is_choice_symbol_ = False
+
+        # This records only dependencies specified with 'depends on'. Needed
+        # when determining actual choice items (hrrrr...). See also
+        # Choice._determine_actual_symbols().
+        self.menu_dep = None
+
+        # See Symbol.get_ref/def_locations().
+        self.def_locations = []
+        self.ref_locations = []
+
+        self.user_val = None
+
+        # Flags
+
+        # Should the symbol get an entry in .config?
+        self.write_to_conf = False
+
+        # Caches the calculated value
+        self.cached_value = None
+
+        # Note: An instance variable 'self.dep' gets set on the Symbol in
+        # Config._build_dep(), linking the symbol to the symbols that
+        # immediately depend on it (in a caching/invalidation sense). The total
+        # set of dependent symbols for the symbol (the transitive closure) is
+        # calculated on an as-needed basis in _get_dependent().
+
+        # Caches the total list of dependent symbols. Calculated in
+        # _get_dependent().
+        self.cached_deps = None
+
+        # Does the symbol have an entry in the Kconfig file? The trailing
+        # underscore avoids a collision with is_defined().
+        self.is_defined_ = False
+
+        # Does the symbol get its value in some special way, e.g. from the
+        # environment or by being one of the special symbols n, m, and y? If
+        # so, the value is stored in self.cached_value, which is never
+        # invalidated. The trailing underscore avoids a collision with
+        # is_special().
+        self.is_special_ = False
+
+        # Does the symbol get its value from the environment?
+        self.is_from_env = False
+
+    def _invalidate(self):
+        if self.is_special_:
+            return
+
+        if self.is_choice_symbol_:
+            self.parent._invalidate()
+
+        _HasVisibility._invalidate(self)
+
+        self.write_to_conf = False
+        self.cached_value = None
+
+    def _invalidate_dependent(self):
+        for sym in self._get_dependent():
+            sym._invalidate()
+
+    def _set_user_value_no_invalidate(self, v, suppress_load_warnings):
+        """Like set_user_value(), but does not invalidate any symbols.
+
+        suppress_load_warnings --
+          some warnings are annoying when loading a .config that can be helpful
+          when manually invoking set_user_value(). This flag is set to True to
+          suppress such warnings.
+
+          Perhaps this could be made optional for load_config() instead."""
+
+        if self.is_special_:
+            if self.is_from_env:
+                self.config._warn('attempt to assign the value "{0}" to the '
+                                  'symbol {1}, which gets its value from the '
+                                  'environment. Assignment ignored.'
+                                  .format(v, self.name))
+            else:
+                self.config._warn('attempt to assign the value "{0}" to the '
+                                  'special symbol {1}. Assignment ignored.'
+                                  .format(v, self.name))
+
+            return
+
+
+        if not self.is_defined_:
+            filename, linenr = self.ref_locations[0]
+
+            self.config._undef_assign('attempt to assign the value "{0}" to {1}, '
+                                      "which is referenced at {2}:{3} but never "
+                                      "defined. Assignment ignored."
+                                      .format(v, self.name, filename, linenr))
+            return
+
+        # Check if the value is valid for our type
+
+        if not (( self.type == BOOL     and (v == "n" or v == "y")    ) or
+                ( self.type == TRISTATE and (v == "n" or v == "m" or
+                                             v == "y")                ) or
+                ( self.type == STRING                                 ) or
+                ( self.type == INT      and _is_base_n(v, 10)         ) or
+                ( self.type == HEX      and _is_base_n(v, 16)         )):
+
+            self.config._warn('the value "{0}" is invalid for {1}, which has type {2}. '
+                              "Assignment ignored."
+                              .format(v, self.name, typename[self.type]))
+            return
+
+        if self.prompts == [] and not suppress_load_warnings:
+            self.config._warn('assigning "{0}" to the symbol {1} which '
+                              'lacks prompts and thus has visibility "n". '
+                              'The assignment will have no effect.'
+                              .format(v, self.name))
+
+        self.user_val = v
+
+        if self.is_choice_symbol_ and (self.type == BOOL or
+                                       self.type == TRISTATE):
+            choice = self.parent
+            if v == "y":
+                choice.user_val = self
+                choice.user_mode = "y"
+            elif v == "m":
+                choice.user_val = None
+                choice.user_mode = "m"
+
+    def _unset_user_value_no_recursive_invalidate(self):
+        self._invalidate()
+        self.user_val = None
+
+        if self.is_choice_symbol_:
+            self.parent._unset_user_value()
+
+    def _make_conf(self):
+        if self.already_written:
+            return []
+
+        self.already_written = True
+
+        # Note: write_to_conf is determined in get_value()
+        val = self.get_value()
+        if not self.write_to_conf:
+            return []
+
+        if self.type == BOOL or self.type == TRISTATE:
+            if val == "m" or val == "y":
+                return ["CONFIG_{0}={1}".format(self.name, val)]
+            return ["# CONFIG_{0} is not set".format(self.name)]
+
+        elif self.type == STRING:
+            # Escape \ and "
+            return ['CONFIG_{0}="{1}"'
+                    .format(self.name,
+                            val.replace("\\", "\\\\").replace('"', '\\"'))]
+
+        elif self.type == INT or self.type == HEX:
+            return ["CONFIG_{0}={1}".format(self.name, val)]
+
+        else:
+            _internal_error('Internal error while creating .config: unknown type "{0}".'
+                            .format(self.type))
+
+    def _get_dependent(self):
+        """Returns the set of symbols that should be invalidated if the value
+        of the symbol changes, because they might be affected by the change.
+        Note that this is an internal API -- it's probably of limited
+        usefulness to clients."""
+        if self.cached_deps is not None:
+            return self.cached_deps
+
+        res = set()
+
+        self._add_dependent_ignore_siblings(res)
+        if self.is_choice_symbol_:
+            for s in self.parent.get_symbols():
+                if s is not self:
+                    res.add(s)
+                    s._add_dependent_ignore_siblings(res)
+
+        self.cached_deps = res
+        return res
+
+    def _add_dependent_ignore_siblings(self, to):
+        """Calculating dependencies gets a bit tricky for choice items as they
+        all depend on each other, potentially leading to infinite recursion.
+        This helper function calculates dependencies ignoring the other symbols
+        in the choice. It also works fine for symbols that are not choice
+        items."""
+        for s in self.dep:
+            to.add(s)
+            to |= s._get_dependent()
+
+    def _has_auto_menu_dep_on(self, on):
+        """See Choice._determine_actual_symbols()."""
+        if not isinstance(self.parent, Choice):
+            _internal_error("Attempt to determine auto menu dependency for symbol ouside of choice.")
+
[… more lines in the raw message]

Lines of this file are not shown. View the raw message.

new file mode 100644
index 0000000..5c82b6f

Lines of this file are not shown. View the raw message.

new file mode 100755
index 0000000..4a91a9c
@@ -0,0 +1,348 @@
+#!/usr/bin/env python2
+##
+## gen-manual-lists.py
+##
+## This script generates the following Buildroot manual appendices:
+##  - the package tables (one for the target, the other for host tools);
+##  - the deprecated items.
+##
+## Author(s):
+##  - Samuel Martin <[email protected]>
+##
+## Copyright (C) 2013 Samuel Martin
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, write to the Free Software
+## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##
+
+## Note about python2.
+##
+## This script can currently only be run using python2 interpreter due to
+## its kconfiglib dependency (which is not yet python3 friendly).
+
+from __future__ import print_function
+from __future__ import unicode_literals
+
+import os
+import re
+import sys
+import datetime
+from argparse import ArgumentParser
+
+try:
+    import kconfiglib
+except ImportError:
+    message = """
+Could not find the module 'kconfiglib' in the PYTHONPATH:
+"""
+    message += "\n".join(["  {0}".format(path) for path in sys.path])
+    message += """
+
+Make sure the Kconfiglib directory is in the PYTHONPATH, then relaunch the
+script.
+
+You can get kconfiglib from:
+  https://github.com/ulfalizer/Kconfiglib
+
+
+"""
+    sys.stderr.write(message)
+    raise
+
+
+def get_symbol_subset(root, filter_func):
+    """ Return a generator of kconfig items.
+
+    :param root_item:   Root item of the generated subset of items
+    :param filter_func: Filter function
+
+    """
+    if hasattr(root, "get_items"):
+        get_items = root.get_items
+    elif hasattr(root, "get_top_level_items"):
+        get_items = root.get_top_level_items
+    else:
+        message = "The symbol does not contain any subset of symbols"
+        raise Exception(message)
+    for item in get_items():
+        if item.is_symbol():
+            if not item.prompts:
+                continue
+            if not filter_func(item):
+                continue
+            yield item
+        elif item.is_menu() or item.is_choice():
+            for i in get_symbol_subset(item, filter_func):
+                yield i
+
+
+def get_symbol_parents(item, root=None, enable_choice=False):
+    """ Return the list of the item's parents. The lasst item of the list is
+    the closest parent, the first the furthest.
+
+    :param item:          Item from which the the parent list is generated
+    :param root:          Root item stopping the search (not included in the
+                          parent list)
+    :param enable_choice: Flag enabling choices to appear in the parent list
+
+    """
+    parent = item.get_parent()
+    parents = []
+    while parent and parent != root:
+        if parent.is_menu():
+            parents.append(parent.get_title())
+        elif enable_choice and parent.is_choice():
+            parents.append(parent.prompts[0][0])
+        parent = parent.get_parent()
+    if isinstance(root, kconfiglib.Menu) or \
+            (enable_choice and isinstance(root, kconfiglib.Choice)):
+        parents.append(".")
+    parents.reverse()
+    return parents
+
+
+def format_asciidoc_table(root, get_label_func, filter_func=lambda x: True,
+                          enable_choice=False, sorted=True):
+    """ Return the asciidoc formatted table of the items and their location.
+
+    :param root:           Root item of the item subset
+    :param get_label_func: Item's label getter function
+    :param filter_func:    Filter function to apply on the item subset
+    :param enable_choice:  Enable choices to appear as part of the item's
+                           location
+    :param sorted:         Flag to alphabetically sort the table
+
+    """
+    def _format_entry(label, parents):
+        """ Format an asciidoc table entry.
+
+        """
+        return "| {0:<40} | {1}\n".format(label, " -> ".join(parents))
+
+    lines = []
+    for item in get_symbol_subset(root, filter_func):
+        if not item.is_symbol() or not item.prompts:
+            continue
+        loc = get_symbol_parents(item, root, enable_choice=enable_choice)
+        lines.append(_format_entry(get_label_func(item), loc))
+    if sorted:
+        lines.sort(key=lambda x: x.lower())
+    if hasattr(root, "get_title"):
+        loc_label = get_symbol_parents(root, None, enable_choice=enable_choice)
+        loc_label += [root.get_title(), "..."]
+    else:
+        loc_label = ["Location"]
+    table = "[width=\"90%\",cols=\"^1,4\",options=\"header\"]\n"
+    table += "|===================================================\n"
+    table += _format_entry("Packages", loc_label)
+    table += "\n" + "".join(lines) + "\n"
+    table += "|===================================================\n"
+    return table
+
+
+class Buildroot:
+    """ Buildroot configuration object.
+
+    """
+    root_config = "Config.in"
+    package_dirname = "package"
+    package_prefixes = ["BR2_PACKAGE_", "BR2_PACKAGE_HOST_"]
+    re_pkg_prefix = re.compile(r"^(" + "|".join(package_prefixes) + ").*")
+    deprecated_symbol = "BR2_DEPRECATED"
+    list_in = """\
+//
+// Automatically generated list for Buildroot manual.
+//
+
+{table}
+"""
+
+    list_info = {
+        'target-packages': {
+            'filename': "package-list",
+            'root_menu': "Package Selection for the target",
+            'filter': "_is_package",
+            'sorted': True,
+        },
+        'host-packages': {
+            'filename': "host-package-list",
+            'root_menu': "Host utilities",
+            'filter': "_is_package",
+            'sorted': True,
+        },
+        'deprecated': {
+            'filename': "deprecated-list",
+            'root_menu': None,
+            'filter': "_is_deprecated",
+            'sorted': False,
+        },
+    }
+
+    def __init__(self):
+        self.base_dir = os.environ.get("TOPDIR")
+        self.package_dir = os.path.join(self.base_dir, self.package_dirname)
+        # The kconfiglib requires an environment variable named "srctree" to
+        # load the configuration, so set it.
+        os.environ.update({'srctree': self.base_dir})
+        self.config = kconfiglib.Config(os.path.join(self.base_dir,
+                                                     self.root_config))
+        self._deprecated = self.config.get_symbol(self.deprecated_symbol)
+
+        self.gen_date = datetime.datetime.utcnow()
+        self.br_version_full = os.environ.get("BR2_VERSION_FULL")
+        if self.br_version_full.endswith("-git"):
+            self.br_version_full = self.br_version_full[:-4]
+
+    def _get_package_symbols(self, package_name):
+        """ Return a tuple containing the target and host package symbol.
+
+        """
+        symbols = re.sub("[-+.]", "_", package_name)
+        symbols = symbols.upper()
+        symbols = tuple([prefix + symbols for prefix in self.package_prefixes])
+        return symbols
+
+    def _is_deprecated(self, symbol):
+        """ Return True if the symbol is marked as deprecated, otherwise False.
+
+        """
+        return self._deprecated in symbol.get_referenced_symbols()
+
+    def _is_package(self, symbol):
+        """ Return True if the symbol is a package or a host package, otherwise
+        False.
+
+        """
+        if not self.re_pkg_prefix.match(symbol.get_name()):
+            return False
+        pkg_name = re.sub("BR2_PACKAGE_(HOST_)?(.*)", r"\2", symbol.get_name())
+
+        pattern = "^(HOST_)?" + pkg_name + "$"
+        pattern = re.sub("_", ".", pattern)
+        pattern = re.compile(pattern, re.IGNORECASE)
+        # Here, we cannot just check for the location of the Config.in because
+        # of the "virtual" package.
+        #
+        # So, to check that a symbol is a package (not a package option or
+        # anything else), we check for the existence of the package *.mk file.
+        #
+        # By the way, to actually check for a package, we should grep all *.mk
+        # files for the following regex:
+        # "\$\(eval \$\((host-)?(generic|autotools|cmake)-package\)\)"
+        #
+        # Implementation details:
+        #
+        # * The package list is generated from the *.mk file existence, the
+        #   first time this function is called. Despite the memory consumtion,
+        #   this list is stored because the execution time of this script is
+        #   noticebly shorter than re-scannig the package sub-tree for each
+        #   symbol.
+        if not hasattr(self, "_package_list"):
+            pkg_list = []
+            for _, _, files in os.walk(self.package_dir):
+                for file_ in (f for f in files if f.endswith(".mk")):
+                    pkg_list.append(re.sub(r"(.*?)\.mk", r"\1", file_))
+            setattr(self, "_package_list", pkg_list)
+        for pkg in getattr(self, "_package_list"):
+            if pattern.match(pkg):
+                return True
+        return False
+
+    def _get_symbol_label(self, symbol, mark_deprecated=True):
+        """ Return the label (a.k.a. prompt text) of the symbol.
+
+        :param symbol:          The symbol
+        :param mark_deprecated: Append a 'deprecated' to the label
+
+        """
+        label = symbol.prompts[0][0]
+        if self._is_deprecated(symbol) and mark_deprecated:
+            label += " *(deprecated)*"
+        return label
+
+    def print_list(self, list_type, enable_choice=True, enable_deprecated=True,
+                   dry_run=False, output=None):
+        """ Print the requested list. If not dry run, then the list is
+        automatically written in its own file.
+
+        :param list_type:         The list type to be generated
+        :param enable_choice:     Flag enabling choices to appear in the list
+        :param enable_deprecated: Flag enabling deprecated items to appear in
+                                  the package lists
+        :param dry_run:           Dry run (print the list in stdout instead of
+                                  writing the list file
+
+        """
+        def _get_menu(title):
+            """ Return the first symbol menu matching the given title.
+
+            """
+            menus = self.config.get_menus()
+            menu = [m for m in menus if m.get_title().lower() == title.lower()]
+            if not menu:
+                message = "No such menu: '{0}'".format(title)
+                raise Exception(message)
+            return menu[0]
+
+        list_config = self.list_info[list_type]
+        root_title = list_config.get('root_menu')
+        if root_title:
+            root_item = _get_menu(root_title)
+        else:
+            root_item = self.config
+        filter_ = getattr(self, list_config.get('filter'))
+        filter_func = lambda x: filter_(x)
+        if not enable_deprecated and list_type != "deprecated":
+            filter_func = lambda x: filter_(x) and not self._is_deprecated(x)
+        mark_depr = list_type != "deprecated"
+        get_label = lambda x: self._get_symbol_label(x, mark_depr)
+
+        table = format_asciidoc_table(root_item, get_label,
+                                      filter_func=filter_func,
+                                      enable_choice=enable_choice,
+                                      sorted=list_config.get('sorted'))
+
+        content = self.list_in.format(table=table)
+
+        if dry_run:
+            print(content)
+            return
+        if not output:
+            output = os.path.join(self.base_dir, "docs", "manual",
+                                  list_config.get('filename') + ".txt")
+        print("Writing the {0} list in:\n\t{1}".format(list_type, output))
+        with open(output, 'w') as fout:
+            fout.write(content)
+
+
+if __name__ == '__main__':
+    list_types = ['target-packages', 'host-packages', 'deprecated']
+    parser = ArgumentParser()
+    parser.add_argument("list_type", nargs="?", choices=list_types,
+                        help="""\
+Generate the given list (generate all lists if unspecified)""")
+    parser.add_argument("-n", "--dry-run", dest="dry_run", action='store_true',
+                        help="Output the generated list to stdout")
+    parser.add_argument("--output-target", dest="output_target",
+                        help="Output target package file")
+    parser.add_argument("--output-host", dest="output_host",
+                        help="Output host package file")
+    parser.add_argument("--output-deprecated", dest="output_deprecated",
+                        help="Output deprecated file")
+    args = parser.parse_args()
+    lists = [args.list_type] if args.list_type else list_types
+    buildroot = Buildroot()
+    for list_name in lists:
+        output = getattr(args, "output_" + list_name.split("-", 1)[0])
+        buildroot.print_list(list_name, dry_run=args.dry_run, output=output)

index ef34169..ce54b99 100644
@@ -6,15 +6,26 @@ Appendix
 
 include::makedev-syntax.txt[]
 
+
+// Automatically generated lists:
+
 [[package-list]]
-Available packages
-------------------
-// docs/manaual/pkg-list.txt is generated using the following command:
-// $ git grep -E '\((autotools|cmake|generic)-package\)' package/ |  \
-//     cut -d':' -f1 | grep '\.mk$' | \
-//     sed -e 's;.*\?/\(.*\?\).mk;* \1;' | \
-//     sort > docs/manual/pkg-list.txt
-
-include::pkg-list.txt[]
+Package Selection for the target
+--------------------------------
+
+include::package-list.txt[]
+
+[[host-package-list]]
+Host utilities
+--------------
+
+include::host-package-list.txt[]
+
+[[deprecated-list]]
+Deprecated stuff
+----------------
+
+The following stuff are marked as _deprecated_ in Buildroot due to
+their status either too old or unmaintained.
 
 include::deprecated-list.txt[]

index aa20534..95ccc7c 100644
@@ -1,3 +1,8 @@
+manual-update-lists:
+	@$(call MESSAGE,"Updating the manual lists...")
+	$(Q)BR2_DEFCONFIG="" TOPDIR=$(TOPDIR) \
+		$(TOPDIR)/support/scripts/gen-manual-lists.py
+
 ################################################################################
 # GENDOC -- generates the make targets needed to build a specific type of
 #           asciidoc documentation.

@@ -17,7 +22,8 @@ $(1): $(1)-$(3)
 .PHONY: $(1)-$(3)
 $(1)-$(3): $$(O)/docs/$(1)/$(1).$(4)
 
-$$(O)/docs/$(1)/$(1).$(4): docs/$(1)/$(1).txt $$($(call UPPERCASE,$(1))_SOURCES)
+$$(O)/docs/$(1)/$(1).$(4): docs/$(1)/$(1).txt $$($(call UPPERCASE,$(1))_SOURCES) \
+	manual-update-lists
 	@$(call MESSAGE,"Generating $(5) $(1)...")
 	$(Q)mkdir -p $$(@D)
 	$(Q)a2x $(6) -f $(2) -d book -L -r $(TOPDIR)/docs/images \

@@ -41,7 +47,7 @@ $(call GENDOC_INNER,$(1),epub,epub,epub,EPUB)
 clean: $(1)-clean
 $(1)-clean:
 	$(Q)$(RM) -rf $(O)/docs/$(1)
-.PHONY: $(1) $(1)-clean
+.PHONY: $(1) $(1)-clean manual-update-lists
 endef
 
 MANUAL_SOURCES = $(wildcard docs/manual/*.txt) $(wildcard docs/images/*)

index c462bb1..2b25059 100644
@@ -817,6 +817,8 @@ release: OUT=buildroot-$(BR2_VERSION)
 # Create release tarballs. We need to fiddle a bit to add the generated
 # documentation to the git output
 release:
+	$(warning Make sure the manual is up-to-date. To update the manual, run:)
+	$(warning $$ make manual-update-lists)
 	git archive --format=tar --prefix=$(OUT)/ master > $(OUT).tar
 	$(MAKE) O=$(OUT) manual-html manual-txt manual-pdf
 	tar rf $(OUT).tar $(OUT)

index 6dc87a4..52b6bd4 100644
@@ -1,46 +1,37 @@
-// -*- mode:doc -*- ;
-
-[[deprecated]]
-Deprecated list
----------------
-
-The following stuff are marked as _deprecated_ in Buildroot due to
-their status either too old or unmaintained.
-
-// list generated using the followings command:
-// $ git grep -EB4 'depends on BR2_DEPRECATED'
-// and
-// $ git grep -EB4 'depends on BR2_DEPRECATED' | \
-//     grep -Eo '(:|-).*?(config|comment) BR2_.*'
 //
-// Need manual checks and sorting.
-
-* Packages:
-
-** +busybox+ 1.18.x
-** +customize+
-** +lzma+
-** +microperl+
-** +netkitbase+
-** +netkittelnet+
-** +pkg-config+
-** +squashfs3+
-** +ttcp+
-
-* Toolchain:
-
-** +gdb+ 6.8
-** +gdb+ 7.0.1
-** +gdb+ 7.1
-** +kernel headers+ 2.6.37
-** +kernel headers+ 2.6.38
-** +kernel headers+ 2.6.39
-
-* Bootloaders:
-
-** +u-boot+ 2011-06
-** +u-boot+ 2011-09
+// Automatically generated list for Buildroot manual.
+//
 
-* Output images:
+[width="90%",cols="^1,4",options="header"]
+|===================================================
+| Packages                                 | Location
+
+| documentation on the target              | Build options
+| development files in target filesystem   | Build options
+| Linux 3.1.x kernel headers               | Toolchain -> Kernel Headers
+| Linux 3.3.x kernel headers               | Toolchain -> Kernel Headers
+| Linux 3.5.x kernel headers               | Toolchain -> Kernel Headers
+| Linux 3.6.x kernel headers               | Toolchain -> Kernel Headers
+| uClibc 0.9.31.x                          | Toolchain -> uClibc C library Version
+| binutils 2.20                            | Toolchain -> Binutils Version
+| Build gdb debugger for the Target        | Toolchain
+| gdb 7.2.x                                | Toolchain -> GDB debugger Version
+| gdb 7.3.x                                | Toolchain -> GDB debugger Version
+| lzma                                     | Package Selection for the target -> Compressors and decompressors
+| autoconf                                 | Package Selection for the target -> Development tools
+| automake                                 | Package Selection for the target -> Development tools
+| ccache                                   | Package Selection for the target -> Development tools
+| gcc                                      | Package Selection for the target -> Development tools
+| make                                     | Package Selection for the target -> Development tools
+| pkg-config                               | Package Selection for the target -> Development tools
+| xstroke                                  | Package Selection for the target -> Graphic libraries and applications (graphic/text)
+| squashfs3                                | Package Selection for the target -> Filesystem and flash utilities
+| netkitbase                               | Package Selection for the target -> Networking applications
+| netkittelnet                             | Package Selection for the target -> Networking applications
+| ttcp                                     | Package Selection for the target -> Networking applications
+| 3.x                                      | Filesystem images -> SquashFS version
+| 2011.09                                  | Bootloaders -> U-Boot Version
+| 2011.06                                  | Bootloaders -> U-Boot Version
+
+|===================================================
 
-** squashfs3 image

new file mode 100644
index 0000000..e57aacd
@@ -0,0 +1,22 @@
+//
+// Automatically generated list for Buildroot manual.
+//
+
+[width="90%",cols="^1,4",options="header"]
+|===================================================
+| Packages                                 | Host utilities -> ...
+
+| host dfu-util                            | .
+| host dosfstools                          | .
+| host e2fsprogs                           | .
+| host genimage                            | .
+| host genpart                             | .
+| host lpc3250loader                       | .
+| host mtools                              | .
+| host omap-u-boot-utils                   | .
+| host openocd                             | .
+| host sam-ba                              | .
+| host u-boot tools                        | .
+
+|===================================================
+

950 lines not on this page · raw message

870 lines not on this page · raw message