lexer.rb in radiant-1.0.0.rc1

- old
+ new

@@ -1,13 +1,17 @@
+require 'sass/scss/rx'
+
 require 'strscan'
 
 module Sass
   module Script
     # The lexical analyzer for SassScript.
     # It takes a raw string and converts it to individual tokens
     # that are easier to parse.
     class Lexer
+      include Sass::SCSS::RX
+
       # A struct containing information about an individual token.
       #
       # `type`: \[`Symbol`\]
       # : The type of token.
       #
@@ -17,21 +21,35 @@
       # `line`: \[`Fixnum`\]
       # : The line of the source file on which the token appears.
       #
       # `offset`: \[`Fixnum`\]
       # : The number of bytes into the line the SassScript token appeared.
-      Token = Struct.new(:type, :value, :line, :offset)
+      #
+      # `pos`: \[`Fixnum`\]
+      # : The scanner position at which the SassScript token appeared.
+      Token = Struct.new(:type, :value, :line, :offset, :pos)
 
+      # The line number of the lexer's current position.
+      #
+      # @return [Fixnum]
+      attr_reader :line
+
+      # The number of bytes into the current line
+      # of the lexer's current position.
+      #
+      # @return [Fixnum]
+      attr_reader :offset
+
       # A hash from operator strings to the corresponding token types.
-      # @private
       OPERATORS = {
         '+' => :plus,
         '-' => :minus,
         '*' => :times,
         '/' => :div,
         '%' => :mod,
         '=' => :single_eq,
+        ':' => :colon,
         '(' => :lparen,
         ')' => :rparen,
         ',' => :comma,
         'and' => :and,
         'or' => :or,
@@ -42,40 +60,79 @@
         '<=' => :lte,
         '>' => :gt,
         '<' => :lt,
         '#{' => :begin_interpolation,
         '}' => :end_interpolation,
+        ';' => :semicolon,
+        '{' => :lcurly,
       }
 
+      OPERATORS_REVERSE = Haml::Util.map_hash(OPERATORS) {|k, v| [v, k]}
+
+      TOKEN_NAMES = Haml::Util.map_hash(OPERATORS_REVERSE) {|k, v| [k, v.inspect]}.merge({
+          :const => "variable (e.g. $foo)",
+          :ident => "identifier (e.g. middle)",
+          :bool => "boolean (e.g. true, false)",
+        })
+
       # A list of operator strings ordered with longer names first
       # so that `>` and `<` don't clobber `>=` and `<=`.
-      # @private
       OP_NAMES = OPERATORS.keys.sort_by {|o| -o.size}
 
+      # A sub-list of {OP_NAMES} that only includes operators
+      # with identifier names.
+      IDENT_OP_NAMES = OP_NAMES.select {|k, v| k =~ /^\w+/}
+
       # A hash of regular expressions that are used for tokenizing.
-      # @private
       REGULAR_EXPRESSIONS = {
-        :whitespace => /\s*/,
-        :variable => /!(\w+)/,
-        :ident => /(\\.|[^\s\\+\-*\/%(),=!])+/,
-        :string_end => /((?:\\.|\#(?!\{)|[^"\\#])*)(?:"|(?=#\{))/,
+        :whitespace => /\s+/,
+        :comment => COMMENT,
+        :single_line_comment => SINGLE_LINE_COMMENT,
+        :variable => /([!\$])(#{IDENT})/,
+        :ident => /(#{IDENT})(\()?/,
         :number => /(-)?(?:(\d*\.\d+)|(\d+))([a-zA-Z%]+)?/,
-        :color => /\##{"([0-9a-fA-F]{1,2})" * 3}|(#{Color::HTML4_COLORS.keys.join("|")})/,
+        :color => HEXCOLOR,
         :bool => /(true|false)\b/,
-        :op => %r{(#{Regexp.union(*OP_NAMES.map{|s| Regexp.new(Regexp.escape(s) + (s =~ /\w$/ ? '(?:\b|$)' : ''))})})}
+        :ident_op => %r{(#{Regexp.union(*IDENT_OP_NAMES.map{|s| Regexp.new(Regexp.escape(s) + "(?!#{NMCHAR}|$)")})})},
+        :op => %r{(#{Regexp.union(*OP_NAMES)})},
       }
 
+      class << self
+        private
+        def string_re(open, close)
+          /#{open}((?:\\.|\#(?!\{)|[^#{close}\\#])*)(#{close}|#\{)/
+        end
+      end
+
+      # A hash of regular expressions that are used for tokenizing strings.
+      #
+      # The key is a `[Symbol, Boolean]` pair.
+      # The symbol represents which style of quotation to use,
+      # while the boolean represents whether or not the string
+      # is following an interpolated segment.
+      STRING_REGULAR_EXPRESSIONS = {
+        [:double, false] => string_re('"', '"'),
+        [:single, false] => string_re("'", "'"),
+        [:double, true] => string_re('', '"'),
+        [:single, true] => string_re('', "'"),
+        [:uri, false] => /url\(#{W}(#{URLCHAR}*?)(#{W}\)|#\{)/,
+        [:uri, true] => /(#{URLCHAR}*?)(#{W}\)|#\{)/,
+      }
+
       # @param str [String, StringScanner] The source text to lex
       # @param line [Fixnum] The line on which the SassScript appears.
       #   Used for error reporting
       # @param offset [Fixnum] The number of characters in on which the SassScript appears.
       #   Used for error reporting
-      def initialize(str, line, offset, filename)
+      # @param options [{Symbol => Object}] An options hash;
+      #   see {file:SASS_REFERENCE.md#sass_options the Sass options documentation}
+      def initialize(str, line, offset, options)
         @scanner = str.is_a?(StringScanner) ? str : StringScanner.new(str)
         @line = line
         @offset = offset
-        @filename = filename
+        @options = options
+        @interpolation_stack = []
         @prev = nil
       end
 
       # Moves the lexer forward one token.
       #
@@ -85,110 +142,196 @@
         @tok, tok = nil, @tok
         @prev = tok
         return tok
       end
 
+      # Returns whether or not there's whitespace before the next token.
+      #
+      # @return [Boolean]
+      def whitespace?(tok = @tok)
+        if tok
+          @scanner.string[0...tok.pos] =~ /\s\Z/
+        else
+          @scanner.string[@scanner.pos, 1] =~ /^\s/ ||
+            @scanner.string[@scanner.pos - 1, 1] =~ /\s\Z/
+        end
+      end
+
       # Returns the next token without moving the lexer forward.
       #
       # @return [Token] The next token
       def peek
         @tok ||= read_token
       end
 
+      # Rewinds the underlying StringScanner
+      # to before the token returned by \{#peek}.
+      def unpeek!
+        @scanner.pos = @tok.pos if @tok
+      end
+
       # @return [Boolean] Whether or not there's more source text to lex.
       def done?
-        whitespace unless after_interpolation?
+        whitespace unless after_interpolation? && @interpolation_stack.last
         @scanner.eos? && @tok.nil?
       end
 
+      # @return [Boolean] Whether or not the last token lexed was `:end_interpolation`.
+      def after_interpolation?
+        @prev && @prev.type == :end_interpolation
+      end
+
+      # Raise an error to the effect that `name` was expected in the input stream
+      # and wasn't found.
+      #
+      # This calls \{#unpeek!} to rewind the scanner to immediately after
+      # the last returned token.
+      #
+      # @param name [String] The name of the entity that was expected but not found
+      # @raise [Sass::SyntaxError]
+      def expected!(name)
+        unpeek!
+        Sass::SCSS::Parser.expected(@scanner, name, @line)
+      end
+
+      # Records all non-comment text the lexer consumes within the block
+      # and returns it as a string.
+      #
+      # @yield A block in which text is recorded
+      # @return [String]
+      def str
+        old_pos = @tok ? @tok.pos : @scanner.pos
+        yield
+        new_pos = @tok ? @tok.pos : @scanner.pos
+        @scanner.string[old_pos...new_pos]
+      end
+
       private
 
       def read_token
         return if done?
+        return unless value = token
+        type, val, size = value
+        size ||= @scanner.matched_size
 
-        value = token
-        unless value
-          raise SyntaxError.new("Syntax error in '#{@scanner.string}' at character #{current_position}.")
-        end
-        Token.new(value.first, value.last, @line, last_match_position)
+        val.line = @line if val.is_a?(Script::Node)
+        Token.new(type, val, @line,
+          current_position - size, @scanner.pos - size)
       end
 
       def whitespace
-        @scanner.scan(REGULAR_EXPRESSIONS[:whitespace])
+        nil while scan(REGULAR_EXPRESSIONS[:whitespace]) ||
+          scan(REGULAR_EXPRESSIONS[:comment]) ||
+          scan(REGULAR_EXPRESSIONS[:single_line_comment])
       end
 
       def token
-        return string('') if after_interpolation?
-        variable || string || number || color || bool || op || ident
+        if after_interpolation? && (interp_type = @interpolation_stack.pop)
+          return string(interp_type, true)
+        end
+
+        variable || string(:double, false) || string(:single, false) || number ||
+          color || bool || string(:uri, false) || raw(UNICODERANGE) ||
+          special_fun || ident_op || ident || op
       end
 
       def variable
-        return unless @scanner.scan(REGULAR_EXPRESSIONS[:variable])
-        [:const, @scanner[1]]
+        _variable(REGULAR_EXPRESSIONS[:variable])
       end
 
-      def ident
-        return unless s = @scanner.scan(REGULAR_EXPRESSIONS[:ident])
-        [:ident, s.gsub(/\\(.)/, '\1')]
+      def _variable(rx)
+        line = @line
+        offset = @offset
+        return unless scan(rx)
+        if @scanner[1] == '!' && @scanner[2] != 'important'
+          Script.var_warning(@scanner[2], line, offset + 1, @options[:filename])
+        end
+
+        [:const, @scanner[2]]
       end
 
-      def string(start_char = '"')
-        return unless @scanner.scan(/#{start_char}#{REGULAR_EXPRESSIONS[:string_end]}/)
-        [:string, Script::String.new(@scanner[1].gsub(/\\([^0-9a-f])/, '\1').gsub(/\\([0-9a-f]{1,4})/, "\\\\\\1"))]
+      def ident
+        return unless scan(REGULAR_EXPRESSIONS[:ident])
+        [@scanner[2] ? :funcall : :ident, @scanner[1]]
       end
 
-      def begin_interpolation
-        @scanner.scan
+      def string(re, open)
+        return unless scan(STRING_REGULAR_EXPRESSIONS[[re, open]])
+        if @scanner[2] == '#{' #'
+          @scanner.pos -= 2 # Don't actually consume the #{
+          @interpolation_stack << re
+        end
+        str =
+          if re == :uri
+            Script::String.new("#{'url(' unless open}#{@scanner[1]}#{')' unless @scanner[2] == '#{'}")
+          else
+            Script::String.new(@scanner[1].gsub(/\\(['"]|\#\{)/, '\1'), :string)
+          end
+        [:string, str]
       end
 
       def number
-        return unless @scanner.scan(REGULAR_EXPRESSIONS[:number])
+        return unless scan(REGULAR_EXPRESSIONS[:number])
         value = @scanner[2] ? @scanner[2].to_f : @scanner[3].to_i
         value = -value if @scanner[1]
         [:number, Script::Number.new(value, Array(@scanner[4]))]
       end
 
       def color
-        return unless @scanner.scan(REGULAR_EXPRESSIONS[:color])
-        value = if @scanner[4]
-                  color = Color::HTML4_COLORS[@scanner[4].downcase]
-                else
-                  (1..3).map {|i| @scanner[i]}.map {|num| num.ljust(2, num).to_i(16)}
-                end
+        return unless s = scan(REGULAR_EXPRESSIONS[:color])
+        raise Sass::SyntaxError.new(<<MESSAGE.rstrip) unless s.size == 4 || s.size == 7
+Colors must have either three or six digits: '#{s}'
+MESSAGE
+        value = s.scan(/^#(..?)(..?)(..?)$/).first.
+          map {|num| num.ljust(2, num).to_i(16)}
         [:color, Script::Color.new(value)]
       end
 
       def bool
-        return unless s = @scanner.scan(REGULAR_EXPRESSIONS[:bool])
+        return unless s = scan(REGULAR_EXPRESSIONS[:bool])
         [:bool, Script::Bool.new(s == 'true')]
       end
 
-      def op
-        prev_chr = @scanner.string[@scanner.pos - 1].chr
-        return unless op = @scanner.scan(REGULAR_EXPRESSIONS[:op])
-        if @prev && op == '-' && prev_chr !~ /\s/ &&
-            [:bool, :ident, :const].include?(@prev.type)
-          warn(<<END)
-DEPRECATION WARNING:
-On line #{@line}, character #{last_match_position}#{" of '#{@filename}'" if @filename}
-- will be allowed as part of variable names in version 3.0.
-Please add whitespace to separate it from the previous token.
-END
-        end
+      def special_fun
+        return unless str1 = scan(/((-[\w-]+-)?calc|expression|progid:[a-z\.]*)\(/i)
+        str2, _ = Haml::Shared.balance(@scanner, ?(, ?), 1)
+        c = str2.count("\n")
+        old_line = @line
+        old_offset = @offset
+        @line += c
+        @offset = (c == 0 ? @offset + str2.size : str2[/\n(.*)/, 1].size)
+        [:special_fun,
+          Haml::Util.merge_adjacent_strings(
+            [str1] + Sass::Engine.parse_interp(str2, old_line, old_offset, @options)),
+          str1.size + str2.size]
+      end
 
+      def ident_op
+        return unless op = scan(REGULAR_EXPRESSIONS[:ident_op])
         [OPERATORS[op]]
       end
 
-      def current_position
-        @offset + @scanner.pos + 1
+      def op
+        return unless op = scan(REGULAR_EXPRESSIONS[:op])
+        @interpolation_stack << nil if op == :begin_interpolation
+        [OPERATORS[op]]
       end
 
-      def last_match_position
-        current_position - @scanner.matched_size
+      def raw(rx)
+        return unless val = scan(rx)
+        [:raw, val]
       end
 
-      def after_interpolation?
-        @prev && @prev.type == :end_interpolation
+      def scan(re)
+        return unless str = @scanner.scan(re)
+        c = str.count("\n")
+        @line += c
+        @offset = (c == 0 ? @offset + str.size : str[/\n(.*)/, 1].size)
+        str
+      end
+
+      def current_position
+        @offset + 1
       end
     end
   end
 end