path: root/actionpack/lib/action_dispatch/journey/scanner.rb

require 'strscan'

module ActionDispatch
  module Journey
    class Scanner
      def initialize
        @ss = nil
      end

      def scan_setup str
        @ss = StringScanner.new str
      end

      def eos?
        @ss.eos?
      end

      def pos
        @ss.pos
      end

      def pre_match
        @ss.pre_match
      end

      def next_token
        return if @ss.eos?

        until token = scan || @ss.eos?; end
        token
      end

      private
      def scan
        case
          # /
        when text = @ss.scan(/\//)
          [:SLASH, text]
        when text = @ss.scan(/\*\w+/)
          [:STAR, text]
        when text = @ss.scan(/\(/)
          [:LPAREN, text]
        when text = @ss.scan(/\)/)
          [:RPAREN, text]
        when text = @ss.scan(/\|/)
          [:OR, text]
        when text = @ss.scan(/\./)
          [:DOT, text]
        when text = @ss.scan(/:\w+/)
          [:SYMBOL, text]
        when text = @ss.scan(/[\w%\-~]+/)
          [:LITERAL, text]
          # any char
        when text = @ss.scan(/./)
          [:LITERAL, text]
        end
      end
    end
  end
end