RDoc::CrossReference is a reusable way to create cross references for names.
Version of CROSSREF_REGEXP used when --hyperlink-all is specified.
Regular expression to match class references
There can be a '\' in front of text to suppress the cross-reference
There can be a '::' in front of class names to reference from the top-level namespace.
The method can be followed by parenthesis (not recommended)
Regular expressions matching text that should potentially have cross-reference links generated are passed to add_regexp_handling. Note that these expressions are meant to pick up text for which cross-references have been suppressed, since the suppression characters are removed by the code that is triggered.
Regular expression to match method references.
See CLASS_REGEXP_STR
Allows cross-references to be created based on the given context (RDoc::Context).
 
               # File ruby-3.1.2/lib/rdoc/cross_reference.rb, line 111
def initialize context
  @context = context
  @store   = context.store
  @seen = {}
end
             
            Returns a reference to name.
If the reference is found and name is not documented text will be returned.  If name is escaped name is returned.  If name is not found text is returned.
 
               # File ruby-3.1.2/lib/rdoc/cross_reference.rb, line 171
def resolve name, text
  return @seen[name] if @seen.include? name
  ref = case name
        when /^\\(#{CLASS_REGEXP_STR})$/o then
          @context.find_symbol $1
        else
          @context.find_symbol name
        end
  ref = resolve_method name unless ref
  # Try a page name
  ref = @store.page name if not ref and name =~ /^[\w.]+$/
  ref = nil if RDoc::Alias === ref # external alias, can't link to it
  out = if name == '\\' then
          name
        elsif name =~ /^\\/ then
          # we remove the \ only in front of what we know:
          # other backslashes are treated later, only outside of <tt>
          ref ? $' : name
        elsif ref then
          if ref.display? then
            ref
          else
            text
          end
        else
          text
        end
  @seen[name] = out
  out
end
             
             
               # File ruby-3.1.2/lib/rdoc/cross_reference.rb, line 118
def resolve_method name
  ref = nil
  if /#{CLASS_REGEXP_STR}([.#]|::)#{METHOD_REGEXP_STR}/o =~ name then
    type = $2
    if '.' == type # will find either #method or ::method
      method = $3
    else
      method = "#{type}#{$3}"
    end
    container = @context.find_symbol_module($1)
  elsif /^([.#]|::)#{METHOD_REGEXP_STR}/o =~ name then
    type = $1
    if '.' == type
      method = $2
    else
      method = "#{type}#{$2}"
    end
    container = @context
  else
    type = nil
    container = nil
  end
  if container then
    unless RDoc::TopLevel === container then
      if '.' == type then
        if 'new' == method then # AnyClassName.new will be class method
          ref = container.find_local_symbol method
          ref = container.find_ancestor_local_symbol method unless ref
        else
          ref = container.find_local_symbol "::#{method}"
          ref = container.find_ancestor_local_symbol "::#{method}" unless ref
          ref = container.find_local_symbol "##{method}" unless ref
          ref = container.find_ancestor_local_symbol "##{method}" unless ref
        end
      else
        ref = container.find_local_symbol method
        ref = container.find_ancestor_local_symbol method unless ref
      end
    end
  end
  ref
end