# class RDoc::Parser::C

`RDoc::Parser::C` attempts to parse `C` extension files. It looks for the standard patterns that you find in extensions: `rb_define_class`, `rb_define_method` and so on. It tries to find the corresponding `C` source for the methods and extract comments, but if we fail we don’t worry too much.

The comments associated with a Ruby method are extracted from the `C` comment block associated with the routine that implements that method, that is to say the method whose name is given in the `rb_define_method` call. For example, you might write:

    /*
     * Returns a new array that is a one-dimensional flattening of this
     * array (recursively). That is, for every element that is an array,
     * extract its elements into the new array.
     *
     *    s = [ 1, 2, 3 ]           #=> [1, 2, 3]
     *    t = [ 4, 5, 6, [7, 8] ]   #=> [4, 5, 6, [7, 8]]
     *    a = [ s, t, 9, 10 ]       #=> [[1, 2, 3], [4, 5, 6, [7, 8]], 9, 10]
     *    a.flatten                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
     */
     static VALUE
     rb_ary_flatten(VALUE ary)
     {
         ary = rb_obj_dup(ary);
         rb_ary_flatten_bang(ary);
         return ary;
     }

     ...

     void
     Init_Array(void)
     {
       ...
       rb_define_method(rb_cArray, "flatten", rb_ary_flatten, 0);

Here `RDoc` will determine from the `rb_define_method` line that there’s a method called “flatten” in class `Array`, and will look for the implementation in the method `rb_ary_flatten`. It will then use the comment from that method in the HTML output. This method must be in the same source file as the `rb_define_method`.

The comment blocks may include special directives:

Document-class: `name`

  Documentation for the named class.

Document-module: `name`

  Documentation for the named module.

Document-const: `name`

  Documentation for the named `rb_define_const`.

  Constant values can be supplied on the first line of the comment like so:

      /* 300: The highest possible score in bowling */
      rb_define_const(cFoo, "PERFECT", INT2FIX(300));

  The value can contain internal colons so long as they are escaped with a \

Document-global: `name`

  Documentation for the named `rb_define_global_const`

Document-variable: `name`

  Documentation for the named `rb_define_variable`

Document-method: `method_name`

  Documentation for the named method. Use this when the method name is unambiguous.

Document-method: `ClassName::method_name`

  Documentation for a singleton method in the given class. Use this when the method name alone is ambiguous.

Document-method: `ClassName#method_name`

  Documentation for a instance method in the given class. Use this when the method name alone is ambiguous.

Document-attr: `name`

  Documentation for the named attribute.

call-seq: text up to an empty line

  Because `C` source doesn’t give descriptive names to Ruby-level parameters, you need to document the calling sequence explicitly

In addition, `RDoc` assumes by default that the `C` method implementing a Ruby function is in the same source file as the rb_define_method call. If this isn’t the case, add the comment:

    rb_define_method(....);  // in filename

As an example, we might have an extension that defines multiple classes in its Init_xxx method. We could document them using

    /*
     * Document-class:  MyClass
     *
     * Encapsulate the writing and reading of the configuration
     * file. ...
     */

    /*
     * Document-method: read_value
     *
     * call-seq:
     *   cfg.read_value(key)            -> value
     *   cfg.read_value(key} { |key| }  -> value
     *
     * Return the value corresponding to +key+ from the configuration.
     * In the second form, if the key isn't found, invoke the
     * block and return its value.
     */

### Attributes

classes [R]

Maps `C` variable names to names of Ruby classes or modules

content [RW]

`C` file the parser is parsing

enclosure_dependencies [R]

Dependencies from a missing enclosing class to the classes in `missing_dependencies` that depend upon it.

known_classes [R]

Maps `C` variable names to names of Ruby classes (and singleton classes)

missing_dependencies [R]

Classes found while parsing the `C` file that were not yet registered due to a missing enclosing class. These are processed by `do_missing`

singleton_classes [R]

Maps `C` variable names to names of Ruby singleton classes

top_level [R]

The TopLevel items in the parsed file belong to

### Public Class Methods

new (top_level, file_name, content, options, stats)
Source

    # File lib/rdoc/parser/c.rb, line 171
    def initialize top_level, file_name, content, options, stats
      super

      @known_classes = RDoc::KNOWN_CLASSES.dup
      @content = handle_tab_width handle_ifdefs_in @content
      @file_dir = File.dirname @file_name

      @classes           = load_variable_map :c_class_variables
      @singleton_classes = load_variable_map :c_singleton_class_variables

      @markup = @options.markup

      # class_variable => { function => [method, ...] }
      @methods = Hash.new { |h, f| h[f] = Hash.new { |i, m| i[m] = [] } }

      # missing variable => [handle_class_module arguments]
      @missing_dependencies = {}

      # missing enclosure variable => [dependent handle_class_module arguments]
      @enclosure_dependencies = Hash.new { |h, k| h[k] = [] }
      @enclosure_dependencies.instance_variable_set :@missing_dependencies,
                                                    @missing_dependencies

      @enclosure_dependencies.extend TSort

      def @enclosure_dependencies.tsort_each_node &block
        each_key(&block)
      rescue TSort::Cyclic => e
        cycle_vars = e.message.scan(/"(.*?)"/).flatten

        cycle = cycle_vars.sort.map do |var_name|
          delete var_name

          var_name, type, mod_name, = @missing_dependencies[var_name]

          "#{type} #{mod_name} (#{var_name})"
        end.join ', '

        warn "Unable to create #{cycle} due to a cyclic class or module creation"

        retry
      end

      def @enclosure_dependencies.tsort_each_child node, &block
        fetch(node, []).each(&block)
      end
    end

Prepares for parsing a `C` file. See RDoc::Parser#initialize for details on the arguments.

Calls superclass method `RDoc::Parser::new`

### Public Instance Methods

add_alias (var_name, class_obj, old_name, new_name, comment)
Source

    # File lib/rdoc/parser/c.rb, line 250
    def add_alias(var_name, class_obj, old_name, new_name, comment)
      al = RDoc::Alias.new '', old_name, new_name, ''
      al.singleton = @singleton_classes.key? var_name
      al.comment = comment
      al.record_location @top_level
      class_obj.add_alias al
      @stats.add_alias al
      al
    end

Add alias, either from a direct alias definition, or from two method that reference the same function.

do_aliases ()
Source

    # File lib/rdoc/parser/c.rb, line 222
    def do_aliases
      @content.scan(/rb_define_alias\s*\(
                     \s*(\w+),
                     \s*"(.+?)",
                     \s*"(.+?)"
                     \s*\)/xm) do |var_name, new_name, old_name|
        class_name = @known_classes[var_name]

        unless class_name then
          @options.warn "Enclosing class or module %p for alias %s %s is not known" % [
            var_name, new_name, old_name]
          next
        end

        class_obj = find_class var_name, class_name
        comment = find_alias_comment var_name, new_name, old_name
        comment.normalize
        if comment.to_s.empty? and existing_method = class_obj.method_list.find { |m| m.name == old_name}
          comment = existing_method.comment
        end
        add_alias(var_name, class_obj, old_name, new_name, comment)
      end
    end

Scans `content` for rb_define_alias

do_attrs ()
Source

    # File lib/rdoc/parser/c.rb, line 263
    def do_attrs
      @content.scan(/rb_attr\s*\(
                     \s*(\w+),
                     \s*([\w"()]+),
                     #{BOOL_ARG_PATTERN},
                     #{BOOL_ARG_PATTERN},
                     \s*\w+\);/xmo) do |var_name, attr_name, read, write|
        handle_attr var_name, attr_name, read, write
      end

      @content.scan(%r%rb_define_attr\(
                               \s*([\w\.]+),
                               \s*"([^"]+)",
                               #{BOOL_ARG_PATTERN},
                               #{BOOL_ARG_PATTERN}\);
                  %xmo) do |var_name, attr_name, read, write|
        handle_attr var_name, attr_name, read, write
      end
    end

Scans `content` for rb_attr and rb_define_attr

do_boot_defclass ()
Source

    # File lib/rdoc/parser/c.rb, line 286
    def do_boot_defclass
      @content.scan(/(\w+)\s*=\s*boot_defclass\s*\(\s*"(\w+?)",\s*(\w+?)\s*\)/) do
        |var_name, class_name, parent|
        parent = nil if parent == "0"
        handle_class_module(var_name, :class, class_name, parent, nil)
      end
    end

Scans `content` for boot_defclass

do_classes_and_modules ()
Source

    # File lib/rdoc/parser/c.rb, line 298
    def do_classes_and_modules
      do_boot_defclass if @file_name == "class.c"

      @content.scan(
        %r(
          (?<open>\s*\(\s*) {0}
          (?<close>\s*\)\s*) {0}
          (?<name>\s*"(?<class_name>\w+)") {0}
          (?<parent>\s*(?:
            (?<parent_name>[\w\*\s\(\)\.\->]+) |
            rb_path2class\s*\(\s*"(?<path>[\w:]+)"\s*\)
          )) {0}
          (?<under>\w+) {0}

          (?<var_name>[\w\.]+)\s* =
          \s*rb_(?:
            define_(?:
              class(?: # rb_define_class(name, parent_name)
                \(\s*
                  \g<name>,
                  \g<parent>
                \s*\)
              |
                _under\g<open> # rb_define_class_under(under, name, parent_name...)
                  \g<under>,
                  \g<name>,
                  \g<parent>
                \g<close>
              )
            |
              (?<module>)
              module(?: # rb_define_module(name)
                \g<open>
                  \g<name>
                \g<close>
              |
                _under\g<open> # rb_define_module_under(under, name)
                  \g<under>,
                  \g<name>
                \g<close>
              )
            )
        |
          (?<attributes>(?:\s*"\w+",)*\s*NULL\s*) {0}
          struct_define(?:
            \g<open> # rb_struct_define(name, ...)
              \g<name>,
          |
            _under\g<open> # rb_struct_define_under(under, name, ...)
              \g<under>,
              \g<name>,
          |
            _without_accessor(?:
              \g<open> # rb_struct_define_without_accessor(name, parent_name, ...)
            |
              _under\g<open> # rb_struct_define_without_accessor_under(under, name, parent_name, ...)
                \g<under>,
            )
              \g<name>,
              \g<parent>,
              \s*\w+,        # Allocation function
          )
            \g<attributes>
          \g<close>
        |
          singleton_class\g<open> # rb_singleton_class(target_class_name)
            (?<target_class_name>\w+)
          \g<close>
          )
        )mx
      ) do
        if target_class_name = $~[:target_class_name]
          # rb_singleton_class(target_class_name)
          handle_singleton $~[:var_name], target_class_name
          next
        end

        var_name = $~[:var_name]
        type = $~[:module] ? :module : :class
        class_name = $~[:class_name]
        parent_name = $~[:parent_name] || $~[:path]
        under = $~[:under]
        attributes = $~[:attributes]

        handle_class_module(var_name, type, class_name, parent_name, under)
        if attributes and !parent_name # rb_struct_define *not* without_accessor
          true_flag = 'Qtrue'
          attributes.scan(/"\K\w+(?=")/) do |attr_name|
            handle_attr var_name, attr_name, true_flag, true_flag
          end
        end
      end
    end

Scans `content` for rb_define_class, boot_defclass, rb_define_class_under and rb_singleton_class

do_constants ()
Source

    # File lib/rdoc/parser/c.rb, line 396
    def do_constants
      @content.scan(%r%\Wrb_define_
                     ( variable          |
                       readonly_variable |
                       const             |
                       global_const        )
                 \s*\(
                   (?:\s*(\w+),)?
                   \s*"(\w+)",
                   \s*(.*?)\s*\)\s*;
                   %xm) do |type, var_name, const_name, definition|
        var_name = "rb_cObject" if !var_name or var_name == "rb_mKernel"
        type = "const" if type == "global_const"
        handle_constants type, var_name, const_name, definition
      end

      @content.scan(%r%
                    \Wrb_curses_define_const
                    \s*\(
                      \s*
                      (\w+)
                      \s*
                    \)
                    \s*;%xm) do |consts|
        const = consts.first

        handle_constants 'const', 'mCurses', const, "UINT2NUM(#{const})"
      end

      @content.scan(%r%
                    \Wrb_file_const
                    \s*\(
                      \s*
                      "([^"]+)",
                      \s*
                      (.*?)
                      \s*
                    \)
                    \s*;%xm) do |name, value|
        handle_constants 'const', 'rb_mFConst', name, value
      end
    end

Scans `content` for rb_define_variable, rb_define_readonly_variable, rb_define_const and rb_define_global_const

do_includes ()
Source

    # File lib/rdoc/parser/c.rb, line 443
    def do_includes
      @content.scan(/rb_include_module\s*\(\s*(\w+?),\s*(\w+?)\s*\)/) do |c, m|
        next unless cls = @classes[c]
        m = @known_classes[m] || m

        comment = new_comment '', @top_level, :c
        incl = cls.add_include RDoc::Include.new(m, comment)
        incl.record_location @top_level
      end
    end

Scans `content` for rb_include_module

do_methods ()
Source

    # File lib/rdoc/parser/c.rb, line 459
    def do_methods
      @content.scan(%r%rb_define_
                     (
                        singleton_method |
                        method           |
                        module_function  |
                        private_method
                     )
                     \s*\(\s*([\w\.]+),
                       \s*"([^"]+)",
                       \s*(?:RUBY_METHOD_FUNC\(|VALUEFUNC\(|\(METHOD\))?(\w+)\)?,
                       \s*(-?\w+)\s*\)
                     (?:;\s*/[*/]\s+in\s+(\w+?\.(?:cpp|c|y)))?
                   %xm) do |type, var_name, meth_name, function, param_count, source_file|

        # Ignore top-object and weird struct.c dynamic stuff
        next if var_name == "ruby_top_self"
        next if var_name == "nstr"

        var_name = "rb_cObject" if var_name == "rb_mKernel"
        handle_method(type, var_name, meth_name, function, param_count,
                      source_file)
      end

      @content.scan(%r%rb_define_global_function\s*\(
                               \s*"([^"]+)",
                               \s*(?:RUBY_METHOD_FUNC\(|VALUEFUNC\()?(\w+)\)?,
                               \s*(-?\w+)\s*\)
                  (?:;\s*/[*/]\s+in\s+(\w+?\.[cy]))?
                  %xm) do |meth_name, function, param_count, source_file|
        handle_method("method", "rb_mKernel", meth_name, function, param_count,
                      source_file)
      end

      @content.scan(/define_filetest_function\s*\(
                       \s*"([^"]+)",
                       \s*(?:RUBY_METHOD_FUNC\(|VALUEFUNC\()?(\w+)\)?,
                       \s*(-?\w+)\s*\)/xm) do |meth_name, function, param_count|

        handle_method("method", "rb_mFileTest", meth_name, function, param_count)
        handle_method("singleton_method", "rb_cFile", meth_name, function,
                      param_count)
      end
    end

Scans `content` for rb_define_method, rb_define_singleton_method, rb_define_module_function, rb_define_private_method, rb_define_global_function and define_filetest_function

do_missing ()
Source

    # File lib/rdoc/parser/c.rb, line 508
    def do_missing
      return if @missing_dependencies.empty?

      @enclosure_dependencies.tsort.each do |in_module|
        arguments = @missing_dependencies.delete in_module

        next unless arguments # dependency on existing class

        handle_class_module(*arguments)
      end
    end

Creates classes and module that were missing were defined due to the file order being different than the declaration order.

find_alias_comment (class_name, new_name, old_name)
Source

    # File lib/rdoc/parser/c.rb, line 524
    def find_alias_comment class_name, new_name, old_name
      content =~ %r%((?>/\*.*?\*/\s+))
                    rb_define_alias\(\s*#{Regexp.escape class_name}\s*,
                                     \s*"#{Regexp.escape new_name}"\s*,
                                     \s*"#{Regexp.escape old_name}"\s*\);%xm

      new_comment($1 || '', @top_level, :c)
    end

Finds the comment for an alias on `class_name` from `new_name` to `old_name`

find_attr_comment (var_name, attr_name, read = nil, write = nil)
Source

    # File lib/rdoc/parser/c.rb, line 542
    def find_attr_comment var_name, attr_name, read = nil, write = nil
      attr_name = Regexp.escape attr_name

      rw = if read and write then
             /\s*#{read}\s*,\s*#{write}\s*/xm
           else
             /.*?/m
           end

      comment = if @content =~ %r%((?>/\*.*?\*/\s+))
                                  rb_define_attr\((?:\s*#{var_name},)?\s*
                                                  "#{attr_name}"\s*,
                                                  #{rw}\)\s*;%xm then
                  $1
                elsif @content =~ %r%((?>/\*.*?\*/\s+))
                                     rb_attr\(\s*#{var_name}\s*,
                                              \s*#{attr_name}\s*,
                                              #{rw},.*?\)\s*;%xm then
                  $1
                elsif @content =~ %r%(/\*.*?(?:\s*\*\s*)?)
                                     Document-attr:\s#{attr_name}\s*?\n
                                     ((?>(.|\n)*?\*/))%x then
                  "#{$1}\n#{$2}"
                else
                  ''
                end

      new_comment comment, @top_level, :c
    end

Finds a comment for rb_define_attr, rb_attr or Document-attr.

`var_name` is the `C` class variable the attribute is defined on. `attr_name` is the attribute’s name.

`read` and `write` are the read/write flags (‘1’ or ‘0’). Either both or neither must be provided.

find_body (class_name, meth_name, meth_obj, file_content, quiet = false)
Source

    # File lib/rdoc/parser/c.rb, line 599
    def find_body class_name, meth_name, meth_obj, file_content, quiet = false
      if file_content
        @body_table ||= {}
        @body_table[file_content] ||= gen_body_table file_content
        type, *args = @body_table[file_content][meth_name]
      end

      case type
      when :func_def
        comment = new_comment args[0], @top_level, :c
        body = args[1]
        offset, = args[2]

        comment.remove_private if comment

        # try to find the whole body
        body = $& if /#{Regexp.escape body}[^(]*?\{.*?^\}/m =~ file_content

        # The comment block may have been overridden with a 'Document-method'
        # block. This happens in the interpreter when multiple methods are
        # vectored through to the same C method but those methods are logically
        # distinct (for example Kernel.hash and Kernel.object_id share the same
        # implementation

        override_comment = find_override_comment class_name, meth_obj
        comment = override_comment if override_comment

        comment.normalize
        find_modifiers comment, meth_obj if comment

        #meth_obj.params = params
        meth_obj.start_collecting_tokens
        tk = { :line_no => 1, :char_no => 1, :text => body }
        meth_obj.add_token tk
        meth_obj.comment = comment
        meth_obj.line    = file_content[0, offset].count("\n") + 1

        body
      when :macro_def
        comment = new_comment args[0], @top_level, :c
        body = args[1]
        offset, = args[2]

        find_body class_name, args[3], meth_obj, file_content, true

        comment.normalize
        find_modifiers comment, meth_obj

        meth_obj.start_collecting_tokens
        tk = { :line_no => 1, :char_no => 1, :text => body }
        meth_obj.add_token tk
        meth_obj.comment = comment
        meth_obj.line    = file_content[0, offset].count("\n") + 1

        body
      when :macro_alias
        # with no comment we hope the aliased definition has it and use it's
        # definition

        body = find_body(class_name, args[0], meth_obj, file_content, true)

        return body if body

        @options.warn "No definition for #{meth_name}"
        false
      else # No body, but might still have an override comment
        comment = find_override_comment class_name, meth_obj

        if comment then
          comment.normalize
          find_modifiers comment, meth_obj
          meth_obj.comment = comment

          ''
        else
          @options.warn "No definition for #{meth_name}"
          false
        end
      end
    end

`Find` the `C` code corresponding to a Ruby method

find_class (raw_name, name, base_name = nil)
Source

    # File lib/rdoc/parser/c.rb, line 683
    def find_class(raw_name, name, base_name = nil)
      unless @classes[raw_name]
        if raw_name =~ /^rb_m/
          container = @top_level.add_module RDoc::NormalModule, name
        else
          container = @top_level.add_class RDoc::NormalClass, name
        end
        container.name = base_name if base_name

        container.record_location @top_level
        @classes[raw_name] = container
      end
      @classes[raw_name]
    end

Finds a RDoc::NormalClass or RDoc::NormalModule for `raw_name`

find_class_comment (class_name, class_mod)
Source

    # File lib/rdoc/parser/c.rb, line 724
    def find_class_comment class_name, class_mod
      comment = nil

      if @content =~ %r%
          ((?>/\*.*?\*/\s+))
          (static\s+)?
          void\s+
          Init(?:VM)?_(?i:#{class_name})\s*(?:_\(\s*)?\(\s*(?:void\s*)?\)%xm then
        comment = $1.sub(%r%Document-(?:class|module):\s+#{class_name}%, '')
      elsif @content =~ %r%Document-(?:class|module):\s+#{class_name}\s*?
                           (?:<\s+[:,\w]+)?\n((?>.*?\*/))%xm then
        comment = "/*\n#{$1}"
      elsif @content =~ %r%((?>/\*.*?\*/\s+))
                           ([\w\.\s]+\s* = \s+)?rb_define_(class|module)[\t (]*?"(#{class_name})"%xm then
        comment = $1
      elsif @content =~ %r%((?>/\*.*?\*/\s+))
                           ([\w\. \t]+ = \s+)?rb_define_(class|module)_under[\t\w, (]*?"(#{class_name.split('::').last})"%xm then
        comment = $1
      else
        comment = ''
      end

      comment = new_comment comment, @top_level, :c
      comment.normalize

      look_for_directives_in class_mod, comment

      class_mod.add_comment comment, @top_level
    end

Look for class or module documentation above Init_`class_name`(void), in a Document-class `class_name` (or module) comment or above an rb_define_class (or module). If a comment is supplied above a matching Init_ and a rb_define_class the Init_ comment is used.

    /*
     * This is a comment for Foo
     */
    Init_Foo(void) {
        VALUE cFoo = rb_define_class("Foo", rb_cObject);
    }

    /*
     * Document-class: Foo
     * This is a comment for Foo
     */
    Init_foo(void) {
        VALUE cFoo = rb_define_class("Foo", rb_cObject);
    }

    /*
     * This is a comment for Foo
     */
    VALUE cFoo = rb_define_class("Foo", rb_cObject);

find_const_comment (type, const_name, class_name = nil)
Source

    # File lib/rdoc/parser/c.rb, line 794
    def find_const_comment(type, const_name, class_name = nil)
      @const_table ||= {}
      @const_table[@content] ||= gen_const_table @content
      table = @const_table[@content]

      comment =
        table[[type, const_name]] ||
        (class_name && table[class_name + "::" + const_name]) ||
        table[const_name] ||
        ''

      new_comment comment, @top_level, :c
    end

Finds a comment matching `type` and `const_name` either above the comment or in the matching Document- section.

find_modifiers (comment, meth_obj)
Source

    # File lib/rdoc/parser/c.rb, line 811
    def find_modifiers comment, meth_obj
      comment.normalize
      comment.extract_call_seq meth_obj

      look_for_directives_in meth_obj, comment
    end

Handles modifiers in `comment` and updates `meth_obj` as appropriate.

find_override_comment (class_name, meth_obj)
Source

    # File lib/rdoc/parser/c.rb, line 821
    def find_override_comment class_name, meth_obj
      name = Regexp.escape meth_obj.name
      prefix = Regexp.escape meth_obj.name_prefix

      comment = if @content =~ %r%Document-method:
                                  \s+#{class_name}#{prefix}#{name}
                                  \s*?\n((?>.*?\*/))%xm then
                  "/*#{$1}"
                elsif @content =~ %r%Document-method:
                                     \s#{name}\s*?\n((?>.*?\*/))%xm then
                  "/*#{$1}"
                end

      return unless comment

      new_comment comment, @top_level, :c
    end

Finds a `Document-method` override for `meth_obj` on `class_name`

gen_body_table (file_content)
Source

    # File lib/rdoc/parser/c.rb, line 575
    def gen_body_table file_content
      table = {}
      file_content.scan(%r{
        ((?>/\*.*?\*/\s*)?)
        ((?:\w+\s+){0,2} VALUE\s+(\w+)
          \s*(?:\([^\)]*\))(?:[^\);]|$))
      | ((?>/\*.*?\*/\s*))^\s*(\#\s*define\s+(\w+)\s+(\w+))
      | ^\s*\#\s*define\s+(\w+)\s+(\w+)
      }xm) do
        case
        when name = $3
          table[name] = [:func_def, $1, $2, $~.offset(2)] if !(t = table[name]) || t[0] != :func_def
        when name = $6
          table[name] = [:macro_def, $4, $5, $~.offset(5), $7] if !(t = table[name]) || t[0] == :macro_alias
        when name = $8
          table[name] ||= [:macro_alias, $9]
        end
      end
      table
    end

Generate a Ruby-method table

gen_const_table (file_content)
Source

    # File lib/rdoc/parser/c.rb, line 757
    def gen_const_table file_content
      table = {}
      @content.scan(%r{
        (?<doc>(?>^\s*/\*.*?\*/\s+))
          rb_define_(?<type>\w+)\(\s*(?:\w+),\s*
                             "(?<name>\w+)"\s*,
                             .*?\)\s*;
      | (?<doc>(?>^\s*/\*.*?\*/\s+))
          rb_define_global_(?<type>const)\(\s*
                             "(?<name>\w+)"\s*,
                             .*?\)\s*;
      |  (?<doc>(?>^\s*/\*.*?\*/\s+))
          rb_file_(?<type>const)\(\s*
                             "(?<name>\w+)"\s*,
                             .*?\)\s*;
      |  (?<doc>(?>^\s*/\*.*?\*/\s+))
          rb_curses_define_(?<type>const)\(\s*
                             (?<name>\w+)
                             \s*\)\s*;
      | Document-(?:const|global|variable):\s
          (?<name>(?:\w+::)*\w+)
          \s*?\n(?<doc>(?>.*?\*/))
      }mxi) do
        name, doc, type = $~.values_at(:name, :doc, :type)
        if type
          table[[type, name]] = doc
        else
          table[name] = "/*\n" + doc
        end
      end
      table
    end

Generate a const table

handle_attr (var_name, attr_name, read, write)
Source

    # File lib/rdoc/parser/c.rb, line 843
    def handle_attr(var_name, attr_name, read, write)
      rw = ''
      rw += 'R' if TRUE_VALUES.include?(read)
      rw += 'W' if TRUE_VALUES.include?(write)

      class_name = @known_classes[var_name]

      return unless class_name

      class_obj = find_class var_name, class_name

      return unless class_obj

      comment = find_attr_comment var_name, attr_name
      comment.normalize

      name = attr_name.gsub(/rb_intern(?:_const)?\("([^"]+)"\)/, '\1')

      attr = RDoc::Attr.new '', name, rw, comment

      attr.record_location @top_level
      class_obj.add_attribute attr
      @stats.add_attribute attr
    end

Creates a new RDoc::Attr `attr_name` on class `var_name` that is either `read`, `write` or both

handle_class_module (var_name, type, class_name, parent, in_module)
Source

    # File lib/rdoc/parser/c.rb, line 872
    def handle_class_module(var_name, type, class_name, parent, in_module)
      parent_name = @known_classes[parent] || parent

      if in_module then
        enclosure = @classes[in_module] || @store.find_c_enclosure(in_module)

        if enclosure.nil? and enclosure = @known_classes[in_module] then
          enc_type = /^rb_m/ =~ in_module ? :module : :class
          handle_class_module in_module, enc_type, enclosure, nil, nil
          enclosure = @classes[in_module]
        end

        unless enclosure then
          @enclosure_dependencies[in_module] << var_name
          @missing_dependencies[var_name] =
            [var_name, type, class_name, parent, in_module]

          return
        end
      else
        enclosure = @top_level
      end

      if type == :class then
        full_name = if RDoc::ClassModule === enclosure then
                      enclosure.full_name + "::#{class_name}"
                    else
                      class_name
                    end

        if @content =~ %r%Document-class:\s+#{full_name}\s*<\s+([:,\w]+)% then
          parent_name = $1
        end

        cm = enclosure.add_class RDoc::NormalClass, class_name, parent_name
      else
        cm = enclosure.add_module RDoc::NormalModule, class_name
      end

      cm.record_location enclosure.top_level

      find_class_comment cm.full_name, cm

      case cm
      when RDoc::NormalClass
        @stats.add_class cm
      when RDoc::NormalModule
        @stats.add_module cm
      end

      @classes[var_name] = cm
      @known_classes[var_name] = cm.full_name
      @store.add_c_enclosure var_name, cm
    end

Creates a new RDoc::NormalClass or RDoc::NormalModule based on `type` named `class_name` in `parent` which was assigned to the `C` `var_name`.

handle_constants (type, var_name, const_name, definition)
Source

    # File lib/rdoc/parser/c.rb, line 937
    def handle_constants(type, var_name, const_name, definition)
      class_name = @known_classes[var_name]

      return unless class_name

      class_obj = find_class var_name, class_name, class_name[/::\K[^:]+\z/]

      unless class_obj then
        @options.warn 'Enclosing class or module %p is not known' % [const_name]
        return
      end

      comment = find_const_comment type, const_name, class_name
      comment.normalize

      # In the case of rb_define_const, the definition and comment are in
      # "/* definition: comment */" form.  The literal ':' and '\' characters
      # can be escaped with a backslash.
      if type.downcase == 'const' then
        if /\A(.+?)?:(?!\S)/ =~ comment.text
          new_definition, new_comment = $1, $'

          if !new_definition # Default to literal C definition
            new_definition = definition
          else
            new_definition = new_definition.gsub(/\\([\\:])/, '\1')
          end

          new_definition.sub!(/\A(\s+)/, '')

          new_comment = "#{$1}#{new_comment.lstrip}"

          new_comment = self.new_comment(new_comment, @top_level, :c)

          con = RDoc::Constant.new const_name, new_definition, new_comment
        else
          con = RDoc::Constant.new const_name, definition, comment
        end
      else
        con = RDoc::Constant.new const_name, definition, comment
      end

      con.record_location @top_level
      @stats.add_constant con
      class_obj.add_constant con
    end

Adds constants. By providing some_value: at the start of the comment you can override the `C` value of the comment to give a friendly definition.

    /* 300: The perfect score in bowling */
    rb_define_const(cFoo, "PERFECT", INT2FIX(300));

Will override `INT2FIX(300)` with the value `300` in the output `RDoc`. Values may include quotes and escaped colons (:).

handle_ifdefs_in (body)
Source

    # File lib/rdoc/parser/c.rb, line 987
    def handle_ifdefs_in(body)
      body.gsub(/^#ifdef HAVE_PROTOTYPES.*?#else.*?\n(.*?)#endif.*?\n/m, '\1')
    end

Removes ifdefs that would otherwise confuse us

handle_method (type, var_name, meth_name, function, param_count, source_file = nil)
Source

    # File lib/rdoc/parser/c.rb, line 996
    def handle_method(type, var_name, meth_name, function, param_count,
                      source_file = nil)
      class_name = @known_classes[var_name]
      singleton  = @singleton_classes.key? var_name

      @methods[var_name][function] << meth_name

      return unless class_name

      class_obj = find_class var_name, class_name

      if existing_method = class_obj.method_list.find { |m| m.c_function == function }
        add_alias(var_name, class_obj, existing_method.name, meth_name, existing_method.comment)
      end

      if class_obj then
        if meth_name == 'initialize' then
          meth_name = 'new'
          singleton = true
          type = 'method' # force public
        end

        meth_obj = RDoc::AnyMethod.new '', meth_name
        meth_obj.c_function = function
        meth_obj.singleton =
          singleton || %w[singleton_method module_function].include?(type)

        p_count = Integer(param_count) rescue -1

        if source_file then
          file_name = File.join @file_dir, source_file

          if File.exist? file_name then
            file_content = File.read file_name
          else
            @options.warn "unknown source #{source_file} for #{meth_name} in #{@file_name}"
          end
        else
          file_content = @content
        end

        body = find_body class_name, function, meth_obj, file_content

        if body and meth_obj.document_self then
          meth_obj.params = if p_count < -1 then # -2 is Array
                              '(*args)'
                            elsif p_count == -1 then # argc, argv
                              rb_scan_args body
                            else
                              args = (1..p_count).map { |i| "p#{i}" }
                              "(#{args.join ', '})"
                            end

          meth_obj.record_location @top_level

          if meth_obj.section_title
            class_obj.temporary_section = class_obj.add_section(meth_obj.section_title)
          end
          class_obj.add_method meth_obj

          @stats.add_method meth_obj
          meth_obj.visibility = :private if 'private_method' == type
        end
      end
    end

Adds an RDoc::AnyMethod `meth_name` defined on a class or module assigned to `var_name`. `type` is the type of method definition function used. `singleton_method` and `module_function` create a singleton method.

handle_singleton (sclass_var, class_var)
Source

    # File lib/rdoc/parser/c.rb, line 1066
    def handle_singleton sclass_var, class_var
      class_name = @known_classes[class_var]

      @known_classes[sclass_var]     = class_name
      @singleton_classes[sclass_var] = class_name
    end

Registers a singleton class `sclass_var` as a singleton of `class_var`

load_variable_map (map_name)
Source

    # File lib/rdoc/parser/c.rb, line 1077
    def load_variable_map map_name
      return {} unless files = @store.cache[map_name]
      return {} unless name_map = files[@file_name]

      class_map = {}

      name_map.each do |variable, name|
        next unless mod = @store.find_class_or_module(name)

        class_map[variable] = if map_name == :c_class_variables then
                                mod
                              else
                                name
                              end
        @known_classes[variable] = name
      end

      class_map
    end

Loads the variable map with the given `name` from the `RDoc::Store`, if present.

look_for_directives_in (context, comment)
Source

    # File lib/rdoc/parser/c.rb, line 1107
      def look_for_directives_in context, comment
        @preprocess.handle comment, context do |directive, param|
          case directive
          when 'main' then
            @options.main_page = param

            warn <<~MSG
              The :main: directive is deprecated and will be removed in RDoc 7.

              You can use these options to specify the initial page displayed instead:
              - `--main=#{param}` via the command line
              - `rdoc.main = "#{param}"` if you use `RDoc::Task`
              - `main_page: #{param}` in your `.rdoc_options` file
            MSG
            ''
          when 'title' then
            @options.default_title = param if @options.respond_to? :default_title=

            warn <<~MSG
              The :title: directive is deprecated and will be removed in RDoc 7.

              You can use these options to specify the title displayed instead:
              - `--title=#{param}` via the command line
              - `rdoc.title = "#{param}"` if you use `RDoc::Task`
              - `title: #{param}` in your `.rdoc_options` file
            MSG
            ''
          end
        end

        comment
      end

Look for directives in a normal comment block:

    /*
     * :title: My Awesome Project
     */

This method modifies the `comment` Both :main: and :title: directives are deprecated and will be removed in `RDoc` 7.

new_comment (text = nil, location = nil, language = nil)
Source

    # File lib/rdoc/parser/c.rb, line 1255
    def new_comment text = nil, location = nil, language = nil
      RDoc::Comment.new(text, location, language).tap do |comment|
        comment.format = @markup
      end
    end

Creates a `RDoc::Comment` instance.

rb_scan_args (method_body)
Source

    # File lib/rdoc/parser/c.rb, line 1144
    def rb_scan_args method_body
      method_body =~ /rb_scan_args\((.*?)\)/m
      return '(*args)' unless $1

      $1.split(/,/)[2] =~ /"(.*?)"/ # format argument
      format = $1.split(//)

      lead = opt = trail = 0

      if format.first =~ /\d/ then
        lead = $&.to_i
        format.shift
        if format.first =~ /\d/ then
          opt = $&.to_i
          format.shift
          if format.first =~ /\d/ then
            trail = $&.to_i
            format.shift
            block_arg = true
          end
        end
      end

      if format.first == '*' and not block_arg then
        var = true
        format.shift
        if format.first =~ /\d/ then
          trail = $&.to_i
          format.shift
        end
      end

      if format.first == ':' then
        hash = true
        format.shift
      end

      if format.first == '&' then
        block = true
        format.shift
      end

      # if the format string is not empty there's a bug in the C code, ignore it

      args = []
      position = 1

      (1...(position + lead)).each do |index|
        args << "p#{index}"
      end

      position += lead

      (position...(position + opt)).each do |index|
        args << "p#{index} = v#{index}"
      end

      position += opt

      if var then
        args << '*args'
        position += 1
      end

      (position...(position + trail)).each do |index|
        args << "p#{index}"
      end

      position += trail

      if hash then
        args << "p#{position} = {}"
      end

      args << '&block' if block

      "(#{args.join ', '})"
    end

Extracts parameters from the `method_body` and returns a method parameter string. Follows 1.9.3dev’s scan-arg-spec, see README.EXT

remove_commented_out_lines ()
Source

    # File lib/rdoc/parser/c.rb, line 1227
    def remove_commented_out_lines
      @content = @content.gsub(%r%//.*rb_define_%, '//')
    end

Removes lines that are commented out that might otherwise get picked up when scanning for classes and methods

scan ()
Source

    # File lib/rdoc/parser/c.rb, line 1235
    def scan
      remove_commented_out_lines

      do_classes_and_modules
      do_missing

      do_constants
      do_methods
      do_includes
      do_aliases
      do_attrs

      @store.add_c_variables self

      @top_level
    end

Extracts the classes, modules, methods, attributes, constants and aliases from a `C` file and returns an RDoc::TopLevel for this file