class Sass::Script::Lexer
The lexical analyzer for SassScript. It takes a raw string and converts it to individual tokens that are easier to parse.
Constants
- IDENT_OP_NAMES
A sub-list of {OP_NAMES} that only includes operators with identifier names.
- OPERATORS
A hash from operator strings to the corresponding token types.
- OPERATORS_REVERSE
- OP_NAMES
A list of operator strings ordered with longer names first so that ‘>` and `<` don’t clobber ‘>=` and `<=`.
- PARSEABLE_NUMBER
- REGULAR_EXPRESSIONS
A hash of regular expressions that are used for tokenizing.
- STRING_REGULAR_EXPRESSIONS
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.
- TOKEN_NAMES
- Token
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.
‘source_range`: [`Sass::Source::Range`] : The range in the source file in which the token appeared.
‘pos`: [`Integer`] : The scanner position at which the SassScript token appeared.
Public Class Methods
@param str [String, StringScanner] The source text to lex @param line [Integer] The 1-based line on which the SassScript appears.
Used for error reporting and sourcemap building
@param offset [Integer] The 1-based character (not byte) offset in the line in the source.
Used for error reporting and sourcemap building
@param options [{Symbol => Object}] An options hash;
see {file:SASS_REFERENCE.md#Options the Sass options documentation}
# File lib/sass/script/lexer.rb, line 153 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 @tok = nil @next_tok = nil end
Private Class Methods
# File lib/sass/script/lexer.rb, line 110 def string_re(open, close) /#{open}((?:\\.|\#(?!\{)|[^#{close}\\#])*)(#{close}|#\{)/m end
Public Instance Methods
@return [Boolean] Whether or not the last token lexed was ‘:end_interpolation`.
# File lib/sass/script/lexer.rb, line 226 def after_interpolation? @prev && @prev.type == :end_interpolation end
Returns the given character.
@return [String]
# File lib/sass/script/lexer.rb, line 189 def char(pos = @scanner.pos) @scanner.string[pos, 1] end
@return [Boolean] Whether or not there’s more source text to lex.
# File lib/sass/script/lexer.rb, line 219 def done? return if @next_tok whitespace unless after_interpolation? && !@interpolation_stack.empty? @scanner.eos? && @tok.nil? 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]
# File lib/sass/script/lexer.rb, line 238 def expected!(name) unpeek! Sass::SCSS::Parser.expected(@scanner, name, @line) end
The line number of the lexer’s current position.
@return [Integer]
# File lib/sass/script/lexer.rb, line 29 def line return @line unless @tok @tok.source_range.start_pos.line end
Moves the lexer forward one token.
@return [Token] The token that was moved past
# File lib/sass/script/lexer.rb, line 167 def next @tok ||= read_token @tok, tok = nil, @tok @prev = tok tok end
Consumes and returns single raw character from the input stream.
@return [String]
# File lib/sass/script/lexer.rb, line 196 def next_char unpeek! scan(/./) end
The number of bytes into the current line of the lexer’s current position (1-based).
@return [Integer]
# File lib/sass/script/lexer.rb, line 38 def offset return @offset unless @tok @tok.source_range.start_pos.offset end
Returns the next token without moving the lexer forward.
@return [Token] The next token
# File lib/sass/script/lexer.rb, line 204 def peek @tok ||= read_token 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]
# File lib/sass/script/lexer.rb, line 248 def str old_pos = @tok ? @tok.pos : @scanner.pos yield new_pos = @tok ? @tok.pos : @scanner.pos @scanner.string[old_pos...new_pos] end
Runs a block, and rewinds the state of the lexer to the beginning of the block if it returns ‘nil` or `false`.
# File lib/sass/script/lexer.rb, line 257 def try old_pos = @scanner.pos old_line = @line old_offset = @offset old_interpolation_stack = @interpolation_stack.dup old_prev = @prev old_tok = @tok old_next_tok = @next_tok result = yield return result if result @scanner.pos = old_pos @line = old_line @offset = old_offset @interpolation_stack = old_interpolation_stack @prev = old_prev @tok = old_tok @next_tok = old_next_tok nil end
Rewinds the underlying StringScanner to before the token returned by {#peek}.
# File lib/sass/script/lexer.rb, line 210 def unpeek! raise "[BUG] Can't unpeek before a queued token!" if @next_tok return unless @tok @scanner.pos = @tok.pos @line = @tok.source_range.start_pos.line @offset = @tok.source_range.start_pos.offset end
Returns whether or not there’s whitespace before the next token.
@return [Boolean]
# File lib/sass/script/lexer.rb, line 177 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
Private Instance Methods
# File lib/sass/script/lexer.rb, line 325 def _variable(rx) return unless scan(rx) [:const, Sass::Util.normalize_ident_escapes(@scanner[2])] end
# File lib/sass/script/lexer.rb, line 417 def color return unless @scanner.match?(REGULAR_EXPRESSIONS[:color]) unless @scanner[0].length == 4 || @scanner[0].length == 5 || @scanner[0].length == 7 || @scanner[0].length == 9 return end script_color = Script::Value::Color.from_hex(scan(REGULAR_EXPRESSIONS[:color])) [:color, script_color] end
# File lib/sass/script/lexer.rb, line 394 def id # Colors and ids are tough to tell apart, because they overlap but # neither is a superset of the other. "#xyz" is an id but not a color, # "#000" is a color but not an id, "#abc" is both, and "#0" is neither. # We need to handle all these cases correctly. # # To do so, we first try to parse something as an id. If this works and # the id is also a valid color, we return the color. Otherwise, we # return the id. If it didn't parse as an id, we then try to parse it as # a color. If *this* works, we return the color, and if it doesn't we # give up and throw an error. # # IDs in properties are used in the Basic User Interface Module # (http://www.w3.org/TR/css3-ui/). return unless scan(REGULAR_EXPRESSIONS[:id]) if @scanner[0] =~ /^\#[0-9a-fA-F]+$/ && (@scanner[0].length == 4 || @scanner[0].length == 5 || @scanner[0].length == 7 || @scanner[0].length == 9) return [:color, Script::Value::Color.from_hex(@scanner[0])] end [:ident, Sass::Util.normalize_ident_escapes(@scanner[0])] end
# File lib/sass/script/lexer.rb, line 330 def ident return unless scan(REGULAR_EXPRESSIONS[:ident]) [@scanner[2] ? :funcall : :ident, Sass::Util.normalize_ident_escapes(@scanner[1])] end
# File lib/sass/script/lexer.rb, line 480 def ident_op op = scan(REGULAR_EXPRESSIONS[:ident_op]) return unless op [OPERATORS[op]] end
# File lib/sass/script/lexer.rb, line 362 def number # Handling unary minus is complicated by the fact that whitespace is an # operator in SassScript. We want "1-2" to be parsed as "1 - 2", but we # want "1 -2" to be parsed as "1 (-2)". To accomplish this, we only # parse a unary minus as part of a number literal if there's whitespace # before and not after it. Cases like "(-2)" are handled by the unary # minus logic in the parser instead. if @scanner.peek(1) == '-' return if @scanner.pos == 0 unary_minus_allowed = case @scanner.string[@scanner.pos - 1, 1] when /\s/; true when '/'; @scanner.pos != 1 && @scanner.string[@scanner.pos - 2, 1] == '*' else; false end return unless unary_minus_allowed return unless scan(REGULAR_EXPRESSIONS[:unary_minus_number]) minus = true else return unless scan(REGULAR_EXPRESSIONS[:number]) minus = false end value = (@scanner[1] ? @scanner[1].to_f : @scanner[2].to_i) * (minus ? -1 : 1) value *= 10**@scanner[3].to_i if @scanner[3] units = @scanner[4] units = Sass::Util::normalize_ident_escapes(units) if units script_number = Script::Value::Number.new(value, Array(units)) [:number, script_number] end
# File lib/sass/script/lexer.rb, line 486 def op op = scan(REGULAR_EXPRESSIONS[:op]) return unless op name = OPERATORS[op] @interpolation_stack << nil if name == :begin_interpolation [name] end
# File lib/sass/script/lexer.rb, line 509 def range(start_pos, end_pos = source_position) Sass::Source::Range.new(start_pos, end_pos, @options[:filename], @options[:importer]) end
# File lib/sass/script/lexer.rb, line 494 def raw(rx) val = scan(rx) return unless val [:raw, val] end
# File lib/sass/script/lexer.rb, line 281 def read_token if (tok = @next_tok) @next_tok = nil return tok end return if done? start_pos = source_position value = token return unless value type, val = value Token.new(type, val, range(start_pos), @scanner.pos - @scanner.matched_size) end
# File lib/sass/script/lexer.rb, line 500 def scan(re) str = @scanner.scan(re) return unless str c = str.count("\n") @line += c @offset = (c == 0 ? @offset + str.size : str.size - str.rindex("\n")) str end
# File lib/sass/script/lexer.rb, line 427 def selector start_pos = source_position return unless scan(REGULAR_EXPRESSIONS[:selector]) if @scanner.peek(1) == '&' filename = @options[:filename] Sass::Util.sass_warn <<MESSAGE WARNING on line #{line}, column #{offset}#{" of #{filename}" if filename}: In Sass, "&&" means two copies of the parent selector. You probably want to use "and" instead. MESSAGE end script_selector = Script::Tree::Selector.new script_selector.source_range = range(start_pos) [:selector, script_selector] end
# File lib/sass/script/lexer.rb, line 513 def source_position Sass::Source::Position.new(@line, @offset) end
# File lib/sass/script/lexer.rb, line 444 def special_fun prefix = scan(/((-[\w-]+-)?(calc|element)|expression|progid:[a-z\.]*)\(/i) return unless prefix special_fun_body(1, prefix) end
# File lib/sass/script/lexer.rb, line 450 def special_fun_body(parens, prefix = nil) str = prefix || '' while (scanned = scan(/.*?([()]|\#\{)/m)) str << scanned if scanned[-1] == ?( parens += 1 next elsif scanned[-1] == ?) parens -= 1 next unless parens == 0 else raise "[BUG] Unreachable" unless @scanner[1] == '#{' # ' str.slice!(-2..-1) @interpolation_stack << [:special_fun, parens] start_pos = Sass::Source::Position.new(@line, @offset - 2) @next_tok = Token.new(:string_interpolation, range(start_pos), @scanner.pos - 2) end return [:special_fun, Sass::Script::Value::String.new(str)] end scan(/.*/) expected!('")"') end
# File lib/sass/script/lexer.rb, line 475 def special_val return unless scan(/!#{W}important/i) [:string, Script::Value::String.new("!important")] end
# File lib/sass/script/lexer.rb, line 335 def string(re, open) line, offset = @line, @offset return unless scan(STRING_REGULAR_EXPRESSIONS[re][open]) if @scanner[0] =~ /([^\\]|^)\n/ filename = @options[:filename] Sass::Util.sass_warn <<MESSAGE DEPRECATION WARNING on line #{line}, column #{offset}#{" of #{filename}" if filename}: Unescaped multiline strings are deprecated and will be removed in a future version of Sass. To include a newline in a string, use "\\a" or "\\a " as in CSS. MESSAGE end if @scanner[2] == '#{' # ' @interpolation_stack << [:string, re] start_pos = Sass::Source::Position.new(@line, @offset - 2) @next_tok = Token.new(:string_interpolation, range(start_pos), @scanner.pos - 2) end str = if re == :uri url = "#{'url(' unless open}#{@scanner[1]}#{')' unless @scanner[2] == '#{'}" Script::Value::String.new(url) else Script::Value::String.new(Sass::Script::Value::String.value(@scanner[1]), :string) end [:string, str] end
# File lib/sass/script/lexer.rb, line 301 def token if after_interpolation? interp_type, interp_value = @interpolation_stack.pop if interp_type == :special_fun return special_fun_body(interp_value) elsif interp_type.nil? if @scanner.string[@scanner.pos - 1] == '}' && scan(REGULAR_EXPRESSIONS[:ident]) return [@scanner[2] ? :funcall : :ident, Sass::Util.normalize_ident_escapes(@scanner[1], start: false)] end else raise "[BUG]: Unknown interp_type #{interp_type}" unless interp_type == :string return string(interp_value, true) end end variable || string(:double, false) || string(:single, false) || number || id || color || selector || string(:uri, false) || raw(UNICODERANGE) || special_fun || special_val || ident_op || ident || op end
# File lib/sass/script/lexer.rb, line 321 def variable _variable(REGULAR_EXPRESSIONS[:variable]) end
# File lib/sass/script/lexer.rb, line 295 def whitespace nil while scan(REGULAR_EXPRESSIONS[:whitespace]) || scan(REGULAR_EXPRESSIONS[:comment]) || scan(REGULAR_EXPRESSIONS[:single_line_comment]) end