Class HTML::Selector
In: vendor/rails/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb
Parent: Object

Selects HTML elements using CSS 2 selectors.

The Selector class uses CSS selector expressions to match and select HTML elements.

For example:

  selector = HTML::Selector.new "form.login[action=/login]"

creates a new selector that matches any form element with the class login and an attribute action with the value /login.

Matching Elements

Use the match method to determine if an element matches the selector.

For simple selectors, the method returns an array with that element, or nil if the element does not match. For complex selectors (see below) the method returns an array with all matched elements, of nil if no match found.

For example:

  if selector.match(element)
    puts "Element is a login form"
  end

Selecting Elements

Use the select method to select all matching elements starting with one element and going through all children in depth-first order.

This method returns an array of all matching elements, an empty array if no match is found

For example:

  selector = HTML::Selector.new "input[type=text]"
  matches = selector.select(element)
  matches.each do |match|
    puts "Found text field with name #{match.attributes['name']}"
  end

Expressions

Selectors can match elements using any of the following criteria:

  • name — Match an element based on its name (tag name). For example, p to match a paragraph. You can use * to match any element.
  • #id — Match an element based on its identifier (the id attribute). For example, #page.
  • .class — Match an element based on its class name, all class names if more than one specified.
  • [attr] — Match an element that has the specified attribute.
  • [attr=value] — Match an element that has the specified attribute and value. (More operators are supported see below)
  • :pseudo-class — Match an element based on a pseudo class, such as :nth-child and :empty.
  • :not(expr) — Match an element that does not match the negation expression.

When using a combination of the above, the element name comes first followed by identifier, class names, attributes, pseudo classes and negation in any order. Do not seprate these parts with spaces! Space separation is used for descendant selectors.

For example:

  selector = HTML::Selector.new "form.login[action=/login]"

The matched element must be of type form and have the class login. It may have other classes, but the class login is required to match. It must also have an attribute called action with the value /login.

This selector will match the following element:

  <form class="login form" method="post" action="/login">

but will not match the element:

  <form method="post" action="/logout">

Attribute Values

Several operators are supported for matching attributes:

  • name — The element must have an attribute with that name.
  • name=value — The element must have an attribute with that name and value.
  • name^=value — The attribute value must start with the specified value.
  • name$=value — The attribute value must end with the specified value.
  • name*=value — The attribute value must contain the specified value.
  • name~=word — The attribute value must contain the specified word (space separated).
  • name|=word — The attribute value must start with specified word.

For example, the following two selectors match the same element:

  #my_id
  [id=my_id]

and so do the following two selectors:

  .my_class
  [class~=my_class]

Alternatives, siblings, children

Complex selectors use a combination of expressions to match elements:

  • expr1 expr2 — Match any element against the second expression if it has some parent element that matches the first expression.
  • expr1 > expr2 — Match any element against the second expression if it is the child of an element that matches the first expression.
  • expr1 + expr2 — Match any element against the second expression if it immediately follows an element that matches the first expression.
  • expr1 ~ expr2 — Match any element against the second expression that comes after an element that matches the first expression.
  • expr1, expr2 — Match any element against the first expression, or against the second expression.

Since children and sibling selectors may match more than one element given the first element, the match method may return more than one match.

Pseudo classes

Pseudo classes were introduced in CSS 3. They are most often used to select elements in a given position:

  • :root — Match the element only if it is the root element (no parent element).
  • :empty — Match the element only if it has no child elements, and no text content.
  • :only-child — Match the element if it is the only child (element) of its parent element.
  • :only-of-type — Match the element if it is the only child (element) of its parent element and its type.
  • :first-child — Match the element if it is the first child (element) of its parent element.
  • :first-of-type — Match the element if it is the first child (element) of its parent element of its type.
  • :last-child — Match the element if it is the last child (element) of its parent element.
  • :last-of-type — Match the element if it is the last child (element) of its parent element of its type.
  • :nth-child(b) — Match the element if it is the b-th child (element) of its parent element. The value b specifies its index, starting with 1.
  • :nth-child(an+b) — Match the element if it is the b-th child (element) in each group of a child elements of its parent element.
  • :nth-child(-an+b) — Match the element if it is the first child (element) in each group of a child elements, up to the first b child elements of its parent element.
  • :nth-child(odd) — Match element in the odd position (i.e. first, third). Same as :nth-child(2n+1).
  • :nth-child(even) — Match element in the even position (i.e. second, fourth). Same as :nth-child(2n+2).
  • :nth-of-type(..) — As above, but only counts elements of its type.
  • :nth-last-child(..) — As above, but counts from the last child.
  • :nth-last-of-type(..) — As above, but counts from the last child and only elements of its type.
  • :not(selector) — Match the element only if the element does not match the simple selector.

As you can see, <tt>:nth-child<tt> pseudo class and its varient can get quite tricky and the CSS specification doesn’t do a much better job explaining it. But after reading the examples and trying a few combinations, it’s easy to figure out.

For example:

  table tr:nth-child(odd)

Selects every second row in the table starting with the first one.

  div p:nth-child(4)

Selects the fourth paragraph in the div, but not if the div contains other elements, since those are also counted.

  div p:nth-of-type(4)

Selects the fourth paragraph in the div, counting only paragraphs, and ignoring all other elements.

  div p:nth-of-type(-n+4)

Selects the first four paragraphs, ignoring all others.

And you can always select an element that matches one set of rules but not another using :not. For example:

  p:not(.post)

Matches all paragraphs that do not have the class .post.

Substitution Values

You can use substitution with identifiers, class names and element values. A substitution takes the form of a question mark (?) and uses the next value in the argument list following the CSS expression.

The substitution value may be a string or a regular expression. All other values are converted to strings.

For example:

  selector = HTML::Selector.new "#?", /^\d+$/

matches any element whose identifier consists of one or more digits.

See www.w3.org/TR/css3-selectors/

Methods

Classes and Modules

Class HTML::Selector::InvalidSelectorError

Public Class methods

Creates a new selector for the given class name.

[Source]

     # File vendor/rails/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb, line 213
213:       def for_class(cls)
214:         self.new([".?", cls])
215:       end

Creates a new selector for the given id.

[Source]

     # File vendor/rails/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb, line 222
222:       def for_id(id)
223:         self.new(["#?", id])
224:       end

Creates a new selector from a CSS 2 selector expression.

The first argument is the selector expression. All other arguments are used for value substitution.

Throws InvalidSelectorError is the selector expression is invalid.

[Source]

     # File vendor/rails/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb, line 238
238:     def initialize(selector, *values)
239:       raise ArgumentError, "CSS expression cannot be empty" if selector.empty?
240:       @source = ""
241:       values = values[0] if values.size == 1 && values[0].is_a?(Array)
242:       # We need a copy to determine if we failed to parse, and also
243:       # preserve the original pass by-ref statement.
244:       statement = selector.strip.dup
245:       # Create a simple selector, along with negation.
246:       simple_selector(statement, values).each { |name, value| instance_variable_set("@#{name}", value) }
247: 
248:       # Alternative selector.
249:       if statement.sub!(/^\s*,\s*/, "")
250:         second = Selector.new(statement, values)
251:         (@alternates ||= []) << second
252:         # If there are alternate selectors, we group them in the top selector.
253:         if alternates = second.instance_variable_get(:@alternates)
254:           second.instance_variable_set(:@alternates, nil)
255:           @alternates.concat alternates
256:         end
257:         @source << " , " << second.to_s
258:       # Sibling selector: create a dependency into second selector that will
259:       # match element immediately following this one.
260:       elsif statement.sub!(/^\s*\+\s*/, "")
261:         second = next_selector(statement, values)
262:         @depends = lambda do |element, first|
263:           if element = next_element(element)
264:             second.match(element, first)
265:           end
266:         end
267:         @source << " + " << second.to_s
268:       # Adjacent selector: create a dependency into second selector that will
269:       # match all elements following this one.
270:       elsif statement.sub!(/^\s*~\s*/, "")
271:         second = next_selector(statement, values)
272:         @depends = lambda do |element, first|
273:           matches = []
274:           while element = next_element(element)
275:             if subset = second.match(element, first)
276:               if first && !subset.empty?
277:                 matches << subset.first
278:                 break
279:               else
280:                 matches.concat subset
281:               end
282:             end
283:           end
284:           matches.empty? ? nil : matches
285:         end
286:         @source << " ~ " << second.to_s
287:       # Child selector: create a dependency into second selector that will
288:       # match a child element of this one.
289:       elsif statement.sub!(/^\s*>\s*/, "")
290:         second = next_selector(statement, values)
291:         @depends = lambda do |element, first|
292:           matches = []
293:           element.children.each do |child|
294:             if child.tag? && subset = second.match(child, first)
295:               if first && !subset.empty?
296:                 matches << subset.first
297:                 break
298:               else
299:                 matches.concat subset
300:               end
301:             end
302:           end
303:           matches.empty? ? nil : matches
304:         end
305:         @source << " > " << second.to_s
306:       # Descendant selector: create a dependency into second selector that
307:       # will match all descendant elements of this one. Note,
308:       elsif statement =~ /^\s+\S+/ && statement != selector
309:         second = next_selector(statement, values)
310:         @depends = lambda do |element, first|
311:           matches = []
312:           stack = element.children.reverse
313:           while node = stack.pop
314:             next unless node.tag?
315:             if subset = second.match(node, first)
316:               if first && !subset.empty?
317:                 matches << subset.first
318:                 break
319:               else
320:                 matches.concat subset
321:               end
322:             elsif children = node.children
323:               stack.concat children.reverse
324:             end
325:           end
326:           matches.empty? ? nil : matches
327:         end
328:         @source << " " << second.to_s
329:       else
330:         # The last selector is where we check that we parsed
331:         # all the parts.
332:         unless statement.empty? || statement.strip.empty?
333:           raise ArgumentError, "Invalid selector: #{statement}"
334:         end
335:       end
336:     end

Public Instance methods

Matches an element against the selector.

For a simple selector this method returns an array with the element if the element matches, nil otherwise.

For a complex selector (sibling and descendant) this method returns an array with all matching elements, nil if no match is found.

Use +first_only=true+ if you are only interested in the first element.

For example:

  if selector.match(element)
    puts "Element is a login form"
  end

[Source]

     # File vendor/rails/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb, line 357
357:     def match(element, first_only = false)
358:       # Match element if no element name or element name same as element name
359:       if matched = (!@tag_name || @tag_name == element.name)
360:         # No match if one of the attribute matches failed
361:         for attr in @attributes
362:           if element.attributes[attr[0]] !~ attr[1]
363:             matched = false
364:             break
365:           end
366:         end
367:       end
368: 
369:       # Pseudo class matches (nth-child, empty, etc).
370:       if matched
371:         for pseudo in @pseudo
372:           unless pseudo.call(element)
373:             matched = false
374:             break
375:           end
376:         end
377:       end
378: 
379:       # Negation. Same rules as above, but we fail if a match is made.
380:       if matched && @negation
381:         for negation in @negation
382:           if negation[:tag_name] == element.name
383:             matched = false
384:           else
385:             for attr in negation[:attributes]
386:               if element.attributes[attr[0]] =~ attr[1]
387:                 matched = false
388:                 break
389:               end
390:             end
391:           end
392:           if matched
393:             for pseudo in negation[:pseudo]
394:               if pseudo.call(element)
395:                 matched = false
396:                 break
397:               end
398:             end
399:           end
400:           break unless matched
401:         end
402:       end
403: 
404:       # If element matched but depends on another element (child,
405:       # sibling, etc), apply the dependent matches instead.
406:       if matched && @depends
407:         matches = @depends.call(element, first_only)
408:       else
409:         matches = matched ? [element] : nil
410:       end
411: 
412:       # If this selector is part of the group, try all the alternative
413:       # selectors (unless first_only).
414:       if @alternates && (!first_only || !matches)
415:         @alternates.each do |alternate|
416:           break if matches && first_only
417:           if subset = alternate.match(element, first_only)
418:             if matches
419:               matches.concat subset
420:             else
421:               matches = subset
422:             end
423:           end
424:         end
425:       end
426: 
427:       matches
428:     end

Return the next element after this one. Skips sibling text nodes.

With the name argument, returns the next element with that name, skipping other sibling elements.

[Source]

     # File vendor/rails/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb, line 487
487:     def next_element(element, name = nil)
488:       if siblings = element.parent.children
489:         found = false
490:         siblings.each do |node|
491:           if node.equal?(element)
492:             found = true
493:           elsif found && node.tag?
494:             return node if (name.nil? || node.name == name)
495:           end
496:         end
497:       end
498:       nil
499:     end

Selects and returns an array with all matching elements, beginning with one node and traversing through all children depth-first. Returns an empty array if no match is found.

The root node may be any element in the document, or the document itself.

For example:

  selector = HTML::Selector.new "input[type=text]"
  matches = selector.select(element)
  matches.each do |match|
    puts "Found text field with name #{match.attributes['name']}"
  end

[Source]

     # File vendor/rails/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb, line 447
447:     def select(root)
448:       matches = []
449:       stack = [root]
450:       while node = stack.pop
451:         if node.tag? && subset = match(node, false)
452:           subset.each do |match|
453:             matches << match unless matches.any? { |item| item.equal?(match) }
454:           end
455:         elsif children = node.children
456:           stack.concat children.reverse
457:         end
458:       end
459:       matches
460:     end

Similar to select but returns the first matching element. Returns nil if no element matches the selector.

[Source]

     # File vendor/rails/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb, line 465
465:     def select_first(root)
466:       stack = [root]
467:       while node = stack.pop
468:         if node.tag? && subset = match(node, true)
469:           return subset.first if !subset.empty?
470:         elsif children = node.children
471:           stack.concat children.reverse
472:         end
473:       end
474:       nil
475:     end

Protected Instance methods

Create a regular expression to match an attribute value based on the equality operator (=, ^=, |=, etc).

[Source]

     # File vendor/rails/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb, line 681
681:     def attribute_match(equality, value)
682:       regexp = value.is_a?(Regexp) ? value : Regexp.escape(value.to_s)
683:       case equality
684:         when "=" then
685:           # Match the attribute value in full
686:           Regexp.new("^#{regexp}$")
687:         when "~=" then
688:           # Match a space-separated word within the attribute value
689:           Regexp.new("(^|\s)#{regexp}($|\s)")
690:         when "^="
691:           # Match the beginning of the attribute value
692:           Regexp.new("^#{regexp}")
693:         when "$="
694:           # Match the end of the attribute value
695:           Regexp.new("#{regexp}$")
696:         when "*="
697:           # Match substring of the attribute value
698:           regexp.is_a?(Regexp) ? regexp : Regexp.new(regexp)
699:         when "|=" then
700:           # Match the first space-separated item of the attribute value
701:           Regexp.new("^#{regexp}($|\s)")
702:         else
703:           raise InvalidSelectorError, "Invalid operation/value" unless value.empty?
704:           # Match all attributes values (existence check)
705:           //
706:       end
707:     end

Called to create a dependent selector (sibling, descendant, etc). Passes the remainder of the statement that will be reduced to zero eventually, and array of substitution values.

This method is called from four places, so it helps to put it here for resue. The only logic deals with the need to detect comma separators (alternate) and apply them to the selector group of the top selector.

[Source]

     # File vendor/rails/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb, line 794
794:     def next_selector(statement, values)
795:       second = Selector.new(statement, values)
796:       # If there are alternate selectors, we group them in the top selector.
797:       if alternates = second.instance_variable_get(:@alternates)
798:         second.instance_variable_set(:@alternates, nil)
799:         (@alternates ||= []).concat alternates
800:       end
801:       second
802:     end

Returns a lambda that can match an element against the nth-child pseudo class, given the following arguments:

  • a — Value of a part.
  • b — Value of b part.
  • of_type — True to test only elements of this type (of-type).
  • reverse — True to count in reverse order (last-).

[Source]

     # File vendor/rails/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb, line 716
716:     def nth_child(a, b, of_type, reverse)
717:       # a = 0 means select at index b, if b = 0 nothing selected
718:       return lambda { |element| false } if a == 0 && b == 0
719:       # a < 0 and b < 0 will never match against an index
720:       return lambda { |element| false } if a < 0 && b < 0
721:       b = a + b + 1 if b < 0   # b < 0 just picks last element from each group
722:       b -= 1 unless b == 0  # b == 0 is same as b == 1, otherwise zero based
723:       lambda do |element|
724:         # Element must be inside parent element.
725:         return false unless element.parent && element.parent.tag?
726:         index = 0
727:         # Get siblings, reverse if counting from last.
728:         siblings = element.parent.children
729:         siblings = siblings.reverse if reverse
730:         # Match element name if of-type, otherwise ignore name.
731:         name = of_type ? element.name : nil
732:         found = false
733:         for child in siblings
734:           # Skip text nodes/comments.
735:           if child.tag? && (name == nil || child.name == name)
736:             if a == 0
737:               # Shortcut when a == 0 no need to go past count
738:               if index == b
739:                 found = child.equal?(element)
740:                 break
741:               end
742:             elsif a < 0
743:               # Only look for first b elements
744:               break if index > b
745:               if child.equal?(element)
746:                 found = (index % a) == 0
747:                 break
748:               end
749:             else
750:               # Otherwise, break if child found and count ==  an+b
751:               if child.equal?(element)
752:                 found = (index % a) == b
753:                 break
754:               end
755:             end
756:             index += 1
757:           end
758:         end
759:         found
760:       end
761:     end

Creates a only child lambda. Pass +of-type+ to only look at elements of its type.

[Source]

     # File vendor/rails/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb, line 766
766:     def only_child(of_type)
767:       lambda do |element|
768:         # Element must be inside parent element.
769:         return false unless element.parent && element.parent.tag?
770:         name = of_type ? element.name : nil
771:         other = false
772:         for child in element.parent.children
773:           # Skip text nodes/comments.
774:           if child.tag? && (name == nil || child.name == name)
775:             unless child.equal?(element)
776:               other = true
777:               break
778:             end
779:           end
780:         end
781:         !other
782:       end
783:     end

Creates a simple selector given the statement and array of substitution values.

Returns a hash with the values tag_name, attributes, pseudo (classes) and negation.

Called the first time with can_negate true to allow negation. Called a second time with false since negation cannot be negated.

[Source]

     # File vendor/rails/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb, line 514
514:     def simple_selector(statement, values, can_negate = true)
515:       tag_name = nil
516:       attributes = []
517:       pseudo = []
518:       negation = []
519: 
520:       # Element name. (Note that in negation, this can come at
521:       # any order, but for simplicity we allow if only first).
522:       statement.sub!(/^(\*|[[:alpha:]][\w\-]*)/) do |match|
523:         match.strip!
524:         tag_name = match.downcase unless match == "*"
525:         @source << match
526:         "" # Remove
527:       end
528: 
529:       # Get identifier, class, attribute name, pseudo or negation.
530:       while true
531:         # Element identifier.
532:         next if statement.sub!(/^#(\?|[\w\-]+)/) do |match|
533:           id = $1
534:           if id == "?"
535:             id = values.shift
536:           end
537:           @source << "##{id}"
538:           id = Regexp.new("^#{Regexp.escape(id.to_s)}$") unless id.is_a?(Regexp)
539:           attributes << ["id", id]
540:           "" # Remove
541:         end
542: 
543:         # Class name.
544:         next if statement.sub!(/^\.([\w\-]+)/) do |match|
545:           class_name = $1
546:           @source << ".#{class_name}"
547:           class_name = Regexp.new("(^|\s)#{Regexp.escape(class_name)}($|\s)") unless class_name.is_a?(Regexp)
548:           attributes << ["class", class_name]
549:           "" # Remove
550:         end
551: 
552:         # Attribute value.
553:         next if statement.sub!(/^\[\s*([[:alpha:]][\w\-]*)\s*((?:[~|^$*])?=)?\s*('[^']*'|"[^*]"|[^\]]*)\s*\]/) do |match|
554:           name, equality, value = $1, $2, $3
555:           if value == "?"
556:             value = values.shift
557:           else
558:             # Handle single and double quotes.
559:             value.strip!
560:             if (value[0] == ?" || value[0] == ?') && value[0] == value[-1]
561:               value = value[1..-2]
562:             end
563:           end
564:           @source << "[#{name}#{equality}'#{value}']"
565:           attributes << [name.downcase.strip, attribute_match(equality, value)]
566:           "" # Remove
567:         end
568: 
569:         # Root element only.
570:         next if statement.sub!(/^:root/) do |match|
571:           pseudo << lambda do |element|
572:             element.parent.nil? || !element.parent.tag?
573:           end
574:           @source << ":root"
575:           "" # Remove
576:         end
577: 
578:         # Nth-child including last and of-type.
579:         next if statement.sub!(/^:nth-(last-)?(child|of-type)\((odd|even|(\d+|\?)|(-?\d*|\?)?n([+\-]\d+|\?)?)\)/) do |match|
580:           reverse = $1 == "last-"
581:           of_type = $2 == "of-type"
582:           @source << ":nth-#{$1}#{$2}("
583:           case $3
584:             when "odd"
585:               pseudo << nth_child(2, 1, of_type, reverse)
586:               @source << "odd)"
587:             when "even"
588:               pseudo << nth_child(2, 2, of_type, reverse)
589:               @source << "even)"
590:             when /^(\d+|\?)$/  # b only
591:               b = ($1 == "?" ? values.shift : $1).to_i
592:               pseudo << nth_child(0, b, of_type, reverse)
593:               @source << "#{b})"
594:             when /^(-?\d*|\?)?n([+\-]\d+|\?)?$/
595:               a = ($1 == "?" ? values.shift :
596:                    $1 == "" ? 1 : $1 == "-" ? -1 : $1).to_i
597:               b = ($2 == "?" ? values.shift : $2).to_i
598:               pseudo << nth_child(a, b, of_type, reverse)
599:               @source << (b >= 0 ? "#{a}n+#{b})" : "#{a}n#{b})")
600:             else
601:               raise ArgumentError, "Invalid nth-child #{match}"
602:           end
603:           "" # Remove
604:         end
605:         # First/last child (of type).
606:         next if statement.sub!(/^:(first|last)-(child|of-type)/) do |match|
607:           reverse = $1 == "last"
608:           of_type = $2 == "of-type"
609:           pseudo << nth_child(0, 1, of_type, reverse)
610:           @source << ":#{$1}-#{$2}"
611:           "" # Remove
612:         end
613:         # Only child (of type).
614:         next if statement.sub!(/^:only-(child|of-type)/) do |match|
615:           of_type = $1 == "of-type"
616:           pseudo << only_child(of_type)
617:           @source << ":only-#{$1}"
618:           "" # Remove
619:         end
620: 
621:         # Empty: no child elements or meaningful content (whitespaces
622:         # are ignored).
623:         next if statement.sub!(/^:empty/) do |match|
624:           pseudo << lambda do |element|
625:             empty = true
626:             for child in element.children
627:               if child.tag? || !child.content.strip.empty?
628:                 empty = false
629:                 break
630:               end
631:             end
632:             empty
633:           end
634:           @source << ":empty"
635:           "" # Remove
636:         end
637:         # Content: match the text content of the element, stripping
638:         # leading and trailing spaces.
639:         next if statement.sub!(/^:content\(\s*(\?|'[^']*'|"[^"]*"|[^)]*)\s*\)/) do |match|
640:           content = $1
641:           if content == "?"
642:             content = values.shift
643:           elsif (content[0] == ?" || content[0] == ?') && content[0] == content[-1]
644:             content = content[1..-2]
645:           end
646:           @source << ":content('#{content}')"
647:           content = Regexp.new("^#{Regexp.escape(content.to_s)}$") unless content.is_a?(Regexp)
648:           pseudo << lambda do |element|
649:             text = ""
650:             for child in element.children
651:               unless child.tag?
652:                 text << child.content
653:               end
654:             end
655:             text.strip =~ content
656:           end
657:           "" # Remove
658:         end
659: 
660:         # Negation. Create another simple selector to handle it.
661:         if statement.sub!(/^:not\(\s*/, "")
662:           raise ArgumentError, "Double negatives are not missing feature" unless can_negate
663:           @source << ":not("
664:           negation << simple_selector(statement, values, false)
665:           raise ArgumentError, "Negation not closed" unless statement.sub!(/^\s*\)/, "")
666:           @source << ")"
667:           next
668:         end
669: 
670:         # No match: moving on.
671:         break
672:       end
673: 
674:       # Return hash. The keys are mapped to instance variables.
675:       {:tag_name=>tag_name, :attributes=>attributes, :pseudo=>pseudo, :negation=>negation}
676:     end

[Validate]