gems.sass-3.5.5.lib.sass.script.lexer.rb Maven / Gradle / Ivy
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A Maven Plugin that compiles Sass files.
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.
#
# `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.
Token = Struct.new(:type, :value, :source_range, :pos)
# The line number of the lexer's current position.
#
# @return [Integer]
def line
return @line unless @tok
@tok.source_range.start_pos.line
end
# The number of bytes into the current line
# of the lexer's current position (1-based).
#
# @return [Integer]
def offset
return @offset unless @tok
@tok.source_range.start_pos.offset
end
# A hash from operator strings to the corresponding token types.
OPERATORS = {
'+' => :plus,
'-' => :minus,
'*' => :times,
'/' => :div,
'%' => :mod,
'=' => :single_eq,
':' => :colon,
'(' => :lparen,
')' => :rparen,
'[' => :lsquare,
']' => :rsquare,
',' => :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)")
# 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+/}
PARSEABLE_NUMBER = /(?:(\d*\.\d+)|(\d+))(?:[eE]([+-]?\d+))?(#{UNIT})?/
# 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 => PARSEABLE_NUMBER,
:unary_minus_number => /-#{PARSEABLE_NUMBER}/,
:color => HEXCOLOR,
:id => /##{IDENT}/,
:selector => /&/,
:ident_op => /(#{Regexp.union(*IDENT_OP_NAMES.map do |s|
Regexp.new(Regexp.escape(s) + "(?!#{NMCHAR}|\Z)")
end)})/,
:op => /(#{Regexp.union(*OP_NAMES)})/,
}
class << self
private
def string_re(open, close)
/#{open}((?:\\.|\#(?!\{)|[^#{close}\\#])*)(#{close}|#\{)/m
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('"', '"'),
true => string_re('', '"')
},
:single => {
false => string_re("'", "'"),
true => string_re('', "'")
},
:uri => {
false => /url\(#{W}(#{URLCHAR}*?)(#{W}\)|#\{)/,
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\(#{W}(#{URLCHAR}*?)(#{W}\)|#\{)/,
true => /(#{URLCHAR}*?)(#{W}\)|#\{)/
},
:domain => {
false => /domain\(#{W}(#{URLCHAR}*?)(#{W}\)|#\{)/,
true => /(#{URLCHAR}*?)(#{W}\)|#\{)/
}
}
# @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}
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
# 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
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 given character.
#
# @return [String]
def char(pos = @scanner.pos)
@scanner.string[pos, 1]
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!
return unless @tok
@scanner.pos = @tok.pos
@line = @tok.source_range.start_pos.line
@offset = @tok.source_range.start_pos.offset
end
# @return [Boolean] Whether or not there's more source text to lex.
def done?
return if @next_tok
whitespace unless after_interpolation? && !@interpolation_stack.empty?
@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
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
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 = @interpolation_stack.pop)
interp_type, interp_value = interp
if interp_type == :special_fun
return special_fun_body(interp_value)
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
def variable
_variable(REGULAR_EXPRESSIONS[:variable])
end
def _variable(rx)
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)
line, offset = @line, @offset
return unless scan(STRING_REGULAR_EXPRESSIONS[re][open])
if @scanner[0] =~ /([^\\]|^)\n/
filename = @options[:filename]
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