SoundSoftware Code Site

module CodeRay

  module Scanners

    # Scheme scanner for CodeRay (by closure).

    # Thanks to murphy for putting CodeRay into public.

    class Scheme < Scanner

      # TODO: function defs

      # TODO: built-in functions

      register_for :scheme

      file_extension 'scm'

      CORE_FORMS = %w[

        lambda let let* letrec syntax-case define-syntax let-syntax

        letrec-syntax begin define quote if or and cond case do delay

        quasiquote set! cons force call-with-current-continuation call/cc

      ]

      IDENT_KIND = CaseIgnoringWordList.new(:ident).

        add(CORE_FORMS, :reserved)

      #IDENTIFIER_INITIAL = /[a-z!@\$%&\*\/\:<=>\?~_\^]/i

      #IDENTIFIER_SUBSEQUENT = /#{IDENTIFIER_INITIAL}|\d|\.|\+|-/

      #IDENTIFIER = /#{IDENTIFIER_INITIAL}#{IDENTIFIER_SUBSEQUENT}*|\+|-|\.{3}/

      IDENTIFIER = /[a-zA-Z!@$%&*\/:<=>?~_^][\w!@$%&*\/:<=>?~^.+\-]*|[+-]|\.\.\./

      DIGIT = /\d/

      DIGIT10 = DIGIT

      DIGIT16 = /[0-9a-f]/i

      DIGIT8 = /[0-7]/

      DIGIT2 = /[01]/

      RADIX16 = /\#x/i

      RADIX8 = /\#o/i

      RADIX2 = /\#b/i

      RADIX10 = /\#d/i

      EXACTNESS = /#i|#e/i

      SIGN = /[\+-]?/

      EXP_MARK = /[esfdl]/i

      EXP = /#{EXP_MARK}#{SIGN}#{DIGIT}+/

      SUFFIX = /#{EXP}?/

      PREFIX10 = /#{RADIX10}?#{EXACTNESS}?|#{EXACTNESS}?#{RADIX10}?/

      PREFIX16 = /#{RADIX16}#{EXACTNESS}?|#{EXACTNESS}?#{RADIX16}/

      PREFIX8 = /#{RADIX8}#{EXACTNESS}?|#{EXACTNESS}?#{RADIX8}/

      PREFIX2 = /#{RADIX2}#{EXACTNESS}?|#{EXACTNESS}?#{RADIX2}/

      UINT10 = /#{DIGIT10}+#*/

      UINT16 = /#{DIGIT16}+#*/

      UINT8 = /#{DIGIT8}+#*/

      UINT2 = /#{DIGIT2}+#*/

      DECIMAL = /#{DIGIT10}+#+\.#*#{SUFFIX}|#{DIGIT10}+\.#{DIGIT10}*#*#{SUFFIX}|\.#{DIGIT10}+#*#{SUFFIX}|#{UINT10}#{EXP}/

      UREAL10 = /#{UINT10}\/#{UINT10}|#{DECIMAL}|#{UINT10}/

      UREAL16 = /#{UINT16}\/#{UINT16}|#{UINT16}/

      UREAL8 = /#{UINT8}\/#{UINT8}|#{UINT8}/

      UREAL2 = /#{UINT2}\/#{UINT2}|#{UINT2}/

      REAL10 = /#{SIGN}#{UREAL10}/

      REAL16 = /#{SIGN}#{UREAL16}/

      REAL8 = /#{SIGN}#{UREAL8}/

      REAL2 = /#{SIGN}#{UREAL2}/

      IMAG10 = /i|#{UREAL10}i/

      IMAG16 = /i|#{UREAL16}i/

      IMAG8 = /i|#{UREAL8}i/

      IMAG2 = /i|#{UREAL2}i/

      COMPLEX10 = /#{REAL10}@#{REAL10}|#{REAL10}\+#{IMAG10}|#{REAL10}-#{IMAG10}|\+#{IMAG10}|-#{IMAG10}|#{REAL10}/

      COMPLEX16 = /#{REAL16}@#{REAL16}|#{REAL16}\+#{IMAG16}|#{REAL16}-#{IMAG16}|\+#{IMAG16}|-#{IMAG16}|#{REAL16}/

      COMPLEX8 = /#{REAL8}@#{REAL8}|#{REAL8}\+#{IMAG8}|#{REAL8}-#{IMAG8}|\+#{IMAG8}|-#{IMAG8}|#{REAL8}/

      COMPLEX2 = /#{REAL2}@#{REAL2}|#{REAL2}\+#{IMAG2}|#{REAL2}-#{IMAG2}|\+#{IMAG2}|-#{IMAG2}|#{REAL2}/

      NUM10 = /#{PREFIX10}?#{COMPLEX10}/

      NUM16 = /#{PREFIX16}#{COMPLEX16}/

      NUM8 = /#{PREFIX8}#{COMPLEX8}/

      NUM2 = /#{PREFIX2}#{COMPLEX2}/

      NUM = /#{NUM10}|#{NUM16}|#{NUM8}|#{NUM2}/

    private

      def scan_tokens tokens,options

        state = :initial

        ident_kind = IDENT_KIND

        until eos?

          kind = match = nil

          case state

          when :initial

            if scan(/ \s+ | \\\n /x)

              kind = :space

            elsif scan(/['\(\[\)\]]|#\(/)

              kind = :operator_fat

            elsif scan(/;.*/)

              kind = :comment

            elsif scan(/#\\(?:newline|space|.?)/)

              kind = :char

            elsif scan(/#[ft]/)

              kind = :pre_constant

            elsif scan(/#{IDENTIFIER}/o)

              kind = ident_kind[matched]

            elsif scan(/\./)

              kind = :operator

            elsif scan(/"/)

              tokens << [:open, :string]

              state = :string

              tokens << ['"', :delimiter]

              next

            elsif scan(/#{NUM}/o) and not matched.empty?

              kind = :integer

            elsif getch

              kind = :error

            end

          when :string

            if scan(/[^"\\]+/) or scan(/\\.?/)

              kind = :content

            elsif scan(/"/)

              tokens << ['"', :delimiter]

              tokens << [:close, :string]

              state = :initial

              next

            else

              raise_inspect "else case \" reached; %p not handled." % peek(1),

                tokens, state

            end

          else

            raise "else case reached"

          end

          match ||= matched

          if $CODERAY_DEBUG and not kind

            raise_inspect 'Error token %p in line %d' %

            [[match, kind], line], tokens

          end

          raise_inspect 'Empty token', tokens, state unless match

          tokens << [match, kind]

        end  # until eos

        if state == :string

          tokens << [:close, :string]

        end

        tokens

      end #scan_tokens

    end #class

  end #module scanners

end #module coderay