forked from sass/sass
-
Notifications
You must be signed in to change notification settings - Fork 1
/
lexer.rb
350 lines (307 loc) · 11 KB
/
lexer.rb
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
require 'sass/scss/rx'
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.
#
# `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.
#
# `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.
OPERATORS = {
'+' => :plus,
'-' => :minus,
'*' => :times,
'/' => :div,
'%' => :mod,
'=' => :single_eq,
':' => :colon,
'(' => :lparen,
')' => :rparen,
',' => :comma,
'and' => :and,
'or' => :or,
'not' => :not,
'==' => :eq,
'!=' => :neq,
'>=' => :gte,
'<=' => :lte,
'>' => :gt,
'<' => :lt,
'#{' => :begin_interpolation,
'}' => :end_interpolation,
';' => :semicolon,
'{' => :lcurly,
'...' => :splat,
}
OPERATORS_REVERSE = Sass::Util.map_hash(OPERATORS) {|k, v| [v, k]}
TOKEN_NAMES = Sass::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 `<=`.
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.
REGULAR_EXPRESSIONS = {
:whitespace => /\s+/,
:comment => COMMENT,
:single_line_comment => SINGLE_LINE_COMMENT,
:variable => /(\$)(#{IDENT})/,
:ident => /(#{IDENT})(\()?/,
:number => /(-)?(?:(\d*\.\d+)|(\d+))([a-zA-Z%]+)?/,
:color => HEXCOLOR,
:bool => /(true|false)\b/,
:null => /null\b/,
:ident_op => %r{(#{Regexp.union(*IDENT_OP_NAMES.map{|s| Regexp.new(Regexp.escape(s) + "(?!#{NMCHAR}|\Z)")})})},
: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}\)|#\{)/,
# Defined in https://developer.mozilla.org/en/CSS/@-moz-document as a
# non-standard version of http://www.w3.org/TR/css3-conditional/
[:url_prefix, false] => /url-prefix\(#{W}(#{URLCHAR}*?)(#{W}\)|#\{)/,
[:url_prefix, true] => /(#{URLCHAR}*?)(#{W}\)|#\{)/,
[:domain, false] => /domain\(#{W}(#{URLCHAR}*?)(#{W}\)|#\{)/,
[:domain, 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 and sourcemap building
# @param offset [Fixnum] The character (not byte) offset in the line on which the SassScript appears.
# Used for error reporting and sourcemap building
# @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 : Sass::Util::MultibyteStringScanner.new(str)
@line = line
@offset = offset
@options = options
@interpolation_stack = []
@prev = nil
end
# Moves the lexer forward one token.
#
# @return [Token] The token that was moved past
def next
@tok ||= read_token
@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? && @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
val.line = @line if val.is_a?(Script::Node)
Token.new(type, val, @line,
current_position - size, @scanner.pos - size)
end
def whitespace
nil while scan(REGULAR_EXPRESSIONS[:whitespace]) ||
scan(REGULAR_EXPRESSIONS[:comment]) ||
scan(REGULAR_EXPRESSIONS[:single_line_comment])
end
def token
if after_interpolation? && (interp_type = @interpolation_stack.pop)
return string(interp_type, true)
end
variable || string(:double, false) || string(:single, false) || number ||
color || bool || null || string(:uri, false) || raw(UNICODERANGE) ||
special_fun || special_val || ident_op || ident || op
end
def variable
_variable(REGULAR_EXPRESSIONS[:variable])
end
def _variable(rx)
line = @line
offset = @offset
return unless scan(rx)
[:const, @scanner[2]]
end
def ident
return unless scan(REGULAR_EXPRESSIONS[:ident])
[@scanner[2] ? :funcall : :ident, @scanner[1]]
end
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 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 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 = scan(REGULAR_EXPRESSIONS[:bool])
[:bool, Script::Bool.new(s == 'true')]
end
def null
return unless scan(REGULAR_EXPRESSIONS[:null])
[:null, Script::Null.new]
end
def special_fun
return unless str1 = scan(/((-[\w-]+-)?(calc|element)|expression|progid:[a-z\.]*)\(/i)
str2, _ = Sass::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,
Sass::Util.merge_adjacent_strings(
[str1] + Sass::Engine.parse_interp(str2, old_line, old_offset, @options)),
str1.size + str2.size]
end
def special_val
return unless scan(/!important/i)
[:string, Script::String.new("!important")]
end
def ident_op
return unless op = scan(REGULAR_EXPRESSIONS[:ident_op])
[OPERATORS[op]]
end
def op
return unless op = scan(REGULAR_EXPRESSIONS[:op])
@interpolation_stack << nil if op == :begin_interpolation
[OPERATORS[op]]
end
def raw(rx)
return unless val = scan(rx)
[:raw, val]
end
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