A parser is simple a class that implements
#initialize(file_name, body, options)
and
#scan
The initialize method takes a file name to be used, the body of the file, and an RDoc::Options object. The scan method is then called to return an appropriately parsed TopLevel code object.
The ParseFactory is used to redirect to the correct parser given a filename extension. This magic works because individual parsers have to register themselves with us as they are loaded in. The do this using the following incantation
require "rdoc/parser" class RDoc::Parser::Xyz < RDoc::Parser parse_files_matching /\.xyz$/ # <<<< def initialize(file_name, body, options) ... end def scan ... end end
Just to make life interesting, if we suspect a plain text file, we also look for a shebang line just in case it's a potential shell script
Alias an extension to another extension. After this call, files ending “new_ext” will be parsed using the same parser as “old_ext”
# File rdoc/parser.rb, line 53 def self.alias_extension(old_ext, new_ext) old_ext = old_ext.sub(/^\.(.*)/, '\1') new_ext = new_ext.sub(/^\.(.*)/, '\1') parser = can_parse "xxx.#{old_ext}" return false unless parser RDoc::Parser.parsers.unshift [/\.#{new_ext}$/, parser] true end
Return a parser that can handle a particular extension
# File rdoc/parser.rb, line 83 def self.can_parse(file_name) parser = RDoc::Parser.parsers.find { |regexp,| regexp =~ file_name }.last # # The default parser should *NOT* parse binary files. # if parser == RDoc::Parser::Simple then if binary? file_name then return nil end end return parser end
Find the correct parser for a particular file name. Return a SimpleParser for ones that we don't know
# File rdoc/parser.rb, line 102 def self.for(top_level, file_name, body, options, stats) # If no extension, look for shebang if file_name !~ /\.\w+$/ && body =~ %r{\A#!(.+)} then shebang = $1 case shebang when %r{env\s+ruby}, %r{/ruby} file_name = "dummy.rb" end end parser = can_parse file_name # # This method must return a parser. # if !parser then parser = RDoc::Parser::Simple end parser.new top_level, file_name, body, options, stats end