module Rouge
  module Lexers
    class IO < RegexLexer
      tag 'io'
      desc 'The IO programming language (http://iolanguage.com)'
      mimetypes 'text/x-iosrc'
      filenames '*.io'

      def self.analyze_text(text)
        return 1 if text.shebang? 'io'
      end

      def self.constants
        @constants ||= Set.new %w(nil false true)
      end

      def self.builtins
        @builtins ||= Set.new %w(
          args call clone do doFile doString else elseif for if list
          method return super then
        )
      end

      state :root do
        rule /\s+/m, 'Text'
        rule %r(//.*?\n), 'Comment.Single'
        rule %r(#.*?\n), 'Comment.Single'
        rule %r(/(\\\n)?[*].*?[*](\\\n)?/)m, 'Comment.Multiline'
        rule %r(/[+]), 'Comment.Multiline', :nested_comment

        rule /"(\\\\|\\"|[^"])*"/, 'Literal.String'

        rule %r(:?:=), 'Keyword'
        rule /[()]/, 'Punctuation'

        rule %r([-=;,*+><!/|^.%&\[\]{}]), 'Operator'

        rule /[A-Z]\w*/, 'Name.Class'

        rule /[a-z_]\w*/ do |m|
          name = m[0]

          if self.class.constants.include? name
            token 'Keyword.Constant'
          elsif self.class.builtins.include? name
            token 'Name.Builtin'
          else
            token 'Name'
          end
        end

        rule %r((\d+[.]?\d*|\d*[.]\d+)(e[+-]?[0-9]+)?)i, 'Literal.Number.Float'
        rule /\d+/, 'Literal.Number.Integer'

        rule /@@?/, 'Keyword'
      end

      state :nested_comment do
        rule %r([^/+]+)m, 'Comment.Multiline'
        rule %r(/[+]), 'Comment.Multiline', :nested_comment
        rule %r([+]/), 'Comment.Multiline', :pop!
      end
    end
  end
end