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/parsers/parsefactory"
module RDoc
class XyzParser
extend ParseFactory <<<<
parse_files_matching /\.xyz$/ <<<<
def initialize(file_name, body, options)
...
end
def scan
...
end
end
end
Just to make life interesting, if we suspect a plain text file, we also look for a shebang line just in case it's a potential shell script
Alias an extension to another extension. After this call, files ending “new_ext” will be parsed using the same parser as “old_ext”
# File rdoc/parsers/parserfactory.rb, line 70
def ParserFactory.alias_extension(old_ext, new_ext)
parser = ParserFactory.can_parse("xxx.#{old_ext}")
return false unless parser
@@parsers.unshift Parsers.new(Regexp.new("\\.#{new_ext}$"), parser.parser)
true
end
Return a parser that can handle a particular extension
# File rdoc/parsers/parserfactory.rb, line 62
def ParserFactory.can_parse(file_name)
@@parsers.find {|p| p.regexp.match(file_name) }
end
Find the correct parser for a particular file name. Return a SimpleParser for ones that we don't know
# File rdoc/parsers/parserfactory.rb, line 80
def ParserFactory.parser_for(top_level, file_name, body, options, stats)
# If no extension, look for shebang
if file_name !~ /\.\w+$/ && body =~ %r{\A#!(.+)}
shebang = $1
case shebang
when %r{env\s+ruby}, %r{/ruby}
file_name = "dummy.rb"
end
end
parser_description = can_parse(file_name)
if parser_description
parser = parser_description.parser
else
parser = SimpleParser
end
parser.new(top_level, file_name, body, options, stats)
end