The lexical analyzer for SassScript. It takes a raw string and converts it to individual tokens that are easier to parse.
| Class | Sass::Script::Lexer |
| In: |
lib/sass/script/lexer.rb
|
| Parent: | Object |
The lexical analyzer for SassScript. It takes a raw string and converts it to individual tokens that are easier to parse.
| Token | = | Struct.new(:type, :value, :line, :offset) |
A struct containing information about an individual token.
`type`: \[{Symbol}\] : The type of token. `value`: \[{Object}\] : The Ruby object corresponding to the value of the token. `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. |
|
| OPERATORS | = | { '+' => :plus, '-' => :minus, '*' => :times, '/' => :div, '%' => :mod, '=' => :single_eq, '(' => :lparen, ')' => :rparen, ',' => :comma, 'and' => :and, 'or' => :or, 'not' => :not, '==' => :eq, '!=' => :neq, '>=' => :gte, '<=' => :lte, '>' => :gt, '<' => :lt, '#{' => :begin_interpolation, '}' => :end_interpolation, } | A hash from operator strings to the corresponding token types. | |
| OP_NAMES | = | OPERATORS.keys.sort_by {|o| -o.size} | A list of operator strings ordered with longer names first so that `>` and `<` don‘t clobber `>=` and `<=`. | |
| REGULAR_EXPRESSIONS | = | { :whitespace => /\s*/, :variable => /!(\w+)/, :ident => /(\\.|[^\s\\+\-*\/%(),=!])+/, :string_end => /((?:\\.|\#(?!\{)|[^"\\#])*)(?:"|(?=#\{))/, :number => /(-)?(?:(\d*\.\d+)|(\d+))([a-zA-Z%]+)?/, :color => /\##{"([0-9a-fA-F]{1,2})" * 3}|(#{Color::HTML4_COLORS.keys.join("|")})/, :bool => /(true|false)\b/, :op => %r{(#{Regexp.union(*OP_NAMES.map{|s| Regexp.new(Regexp.escape(s) + (s =~ /\w$/ ? '(?:\b|$)' : ''))})})} | A hash of regular expressions that are used for tokenizing. |
@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
# File lib/sass/script/lexer.rb, line 69
69: def initialize(str, line, offset, filename)
70: @scanner = str.is_a?(StringScanner) ? str : StringScanner.new(str)
71: @line = line
72: @offset = offset
73: @filename = filename
74: @prev = nil
75: end
@return [Boolean] Whether or not there‘s more source text to lex.
# File lib/sass/script/lexer.rb, line 95
95: def done?
96: whitespace unless after_interpolation?
97: @scanner.eos? && @tok.nil?
98: end
# File lib/sass/script/lexer.rb, line 187
187: def after_interpolation?
188: @prev && @prev.type == :end_interpolation
189: end
# File lib/sass/script/lexer.rb, line 157
157: def bool
158: return unless s = @scanner.scan(REGULAR_EXPRESSIONS[:bool])
159: [:bool, Script::Bool.new(s == 'true')]
160: end
# File lib/sass/script/lexer.rb, line 147
147: def color
148: return unless @scanner.scan(REGULAR_EXPRESSIONS[:color])
149: value = if @scanner[4]
150: color = Color::HTML4_COLORS[@scanner[4].downcase]
151: else
152: (1..3).map {|i| @scanner[i]}.map {|num| num.ljust(2, num).to_i(16)}
153: end
154: [:color, Script::Color.new(value)]
155: end
# File lib/sass/script/lexer.rb, line 179
179: def current_position
180: @offset + @scanner.pos + 1
181: end
# File lib/sass/script/lexer.rb, line 126
126: def ident
127: return unless s = @scanner.scan(REGULAR_EXPRESSIONS[:ident])
128: [:ident, s.gsub(/\\(.)/, '\1')]
129: end
# File lib/sass/script/lexer.rb, line 183
183: def last_match_position
184: current_position - @scanner.matched_size
185: end
# File lib/sass/script/lexer.rb, line 140
140: def number
141: return unless @scanner.scan(REGULAR_EXPRESSIONS[:number])
142: value = @scanner[2] ? @scanner[2].to_f : @scanner[3].to_i
143: value = -value if @scanner[1]
144: [:number, Script::Number.new(value, Array(@scanner[4]))]
145: end
# File lib/sass/script/lexer.rb, line 162
162: def op
163: prev_chr = @scanner.string[@scanner.pos - 1].chr
164: return unless op = @scanner.scan(REGULAR_EXPRESSIONS[:op])
165: if @prev && op == '-' && prev_chr !~ /\s/ &&
166: [:bool, :ident, :const].include?(@prev.type)
167: warn("DEPRECATION WARNING:\nOn line \#{@line}, character \#{last_match_position}\#{\" of '\#{@filename}'\" if @filename}\n- will be allowed as part of variable names in version 2.4.\nPlease add whitespace to separate it from the previous token.\n")
168: end
169:
170: [OPERATORS[op]]
171: end
# File lib/sass/script/lexer.rb, line 102
102: def read_token
103: return if done?
104:
105: value = token
106: unless value
107: raise SyntaxError.new("Syntax error in '#{@scanner.string}' at character #{current_position}.")
108: end
109: Token.new(value.first, value.last, @line, last_match_position)
110: end
# File lib/sass/script/lexer.rb, line 131
131: def string(start_char = '"')
132: return unless @scanner.scan(/#{start_char}#{REGULAR_EXPRESSIONS[:string_end]}/)
133: [:string, Script::String.new(@scanner[1].gsub(/\\([^0-9a-f])/, '\1').gsub(/\\([0-9a-f]{1,4})/, "\\\\\\1"))]
134: end
# File lib/sass/script/lexer.rb, line 116
116: def token
117: return string('') if after_interpolation?
118: variable || string || number || color || bool || op || ident
119: end
# File lib/sass/script/lexer.rb, line 121
121: def variable
122: return unless @scanner.scan(REGULAR_EXPRESSIONS[:variable])
123: [:const, @scanner[1]]
124: end