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

new (str, line, offset, options)

Source

# 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

@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}

Public Instance Methods

after_interpolation? ()

Source

# File lib/sass/script/lexer.rb, line 226
def after_interpolation?
  @prev && @prev.type == :end_interpolation
end

@return [Boolean] Whether or not the last token lexed was ‘:end_interpolation`.

char (pos = @scanner.pos)

Source

# File lib/sass/script/lexer.rb, line 189
def char(pos = @scanner.pos)
  @scanner.string[pos, 1]
end

Returns the given character.

@return [String]

done? ()

Source

# 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

@return [Boolean] Whether or not there’s more source text to lex.

expected! (name)

Source

# File lib/sass/script/lexer.rb, line 238
def expected!(name)
  unpeek!
  Sass::SCSS::Parser.expected(@scanner, name, @line)
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]

line ()

Source

# File lib/sass/script/lexer.rb, line 29
def line
  return @line unless @tok
  @tok.source_range.start_pos.line
end

The line number of the lexer’s current position.

@return [Integer]

next ()

Source

# File lib/sass/script/lexer.rb, line 167
def next
  @tok ||= read_token
  @tok, tok = nil, @tok
  @prev = tok
  tok
end

Moves the lexer forward one token.

@return [Token] The token that was moved past

next_char ()

Source

# File lib/sass/script/lexer.rb, line 196
def next_char
  unpeek!
  scan(/./)
end

Consumes and returns single raw character from the input stream.

@return [String]

offset ()

Source

# File lib/sass/script/lexer.rb, line 38
def offset
  return @offset unless @tok
  @tok.source_range.start_pos.offset
end

The number of bytes into the current line of the lexer’s current position (1-based).

@return [Integer]

peek ()

Source

# File lib/sass/script/lexer.rb, line 204
def peek
  @tok ||= read_token
end

Returns the next token without moving the lexer forward.

@return [Token] The next token

str () { || ... }

Source

# 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

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]

try () { || ... }

Source

# 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

Runs a block, and rewinds the state of the lexer to the beginning of the block if it returns ‘nil` or `false`.

unpeek! ()

Source

# 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

Rewinds the underlying StringScanner to before the token returned by {#peek}.

whitespace? (tok = @tok)

Source

# 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

Returns whether or not there’s whitespace before the next token.

@return [Boolean]