class Sass::Selector::Sequence
An operator-separated sequence of {SimpleSequence simple selector sequences}.
Attributes
The array of {SimpleSequence simple selector sequences}, operators, and newlines. The operators are strings such as ‘“+”` and `“>”` representing the corresponding CSS
operators, or interpolated SassScript. Newlines are also newline strings; these aren’t semantically relevant, but they do affect formatting.
@return [Array<SimpleSequence, String|Array<Sass::Tree::Node, String>>]
Public Class Methods
@param seqs_and_ops [Array<SimpleSequence, String|Array<Sass::Tree::Node, String>>]
See \{#members}
# File lib/sass/selector/sequence.rb, line 38 def initialize(seqs_and_ops) @members = seqs_and_ops end
Public Instance Methods
Add to the {SimpleSequence#sources} sets of the child simple sequences. This destructively modifies this sequence’s members array, but not the child simple sequences.
@param sources [Set<Sequence>]
# File lib/sass/selector/sequence.rb, line 181 def add_sources!(sources) members.map! {|m| m.is_a?(SimpleSequence) ? m.with_more_sources(sources) : m} end
Returns whether there’s a {Parent} selector anywhere in this sequence.
@return [Boolean]
# File lib/sass/selector/sequence.rb, line 83 def contains_parent_ref? members.any? do |sseq_or_op| next false unless sseq_or_op.is_a?(SimpleSequence) next true if sseq_or_op.members.first.is_a?(Parent) sseq_or_op.members.any? do |sel| sel.is_a?(Pseudo) && sel.selector && sel.selector.contains_parent_ref? end end end
Non-destructively extends this selector with the extensions specified in a hash (which should come from {Sass::Tree::Visitors::Cssize}).
@param extends [Sass::Util::SubsetMap{Selector::Simple =>
Sass::Tree::Visitors::Cssize::Extend}] The extensions to perform on this selector
@param parent_directives [Array<Sass::Tree::DirectiveNode>]
The directives containing this selector.
@param replace [Boolean]
Whether to replace the original selector entirely or include it in the result.
@param seen [Set<Array<Selector::Simple>>]
The set of simple sequences that are currently being replaced.
@param original [Boolean]
Whether this is the original selector being extended, as opposed to the result of a previous extension that's being re-extended.
@return [Array<Sequence>] A list of selectors generated
by extending this selector with `extends`. These correspond to a {CommaSequence}'s {CommaSequence#members members array}.
# File lib/sass/selector/sequence.rb, line 113 def do_extend(extends, parent_directives, replace, seen, original) extended_not_expanded = members.map do |sseq_or_op| next [[sseq_or_op]] unless sseq_or_op.is_a?(SimpleSequence) extended = sseq_or_op.do_extend(extends, parent_directives, replace, seen) # The First Law of Extend says that the generated selector should have # specificity greater than or equal to that of the original selector. # In order to ensure that, we record the original selector's # (`extended.first`) original specificity. extended.first.add_sources!([self]) if original && !invisible? extended.map {|seq| seq.members} end weaves = Sass::Util.paths(extended_not_expanded).map {|path| weave(path)} trim(weaves).map {|p| Sequence.new(p)} end
Sets the name of the file in which this selector was declared, or ‘nil` if it was not declared in a file (e.g. on stdin). This also sets the filename for all child selectors.
@param filename [String, nil] @return [String, nil]
# File lib/sass/selector/sequence.rb, line 22 def filename=(filename) members.each {|m| m.filename = filename if m.is_a?(SimpleSequence)} filename end
Returns a string representation of the sequence. This is basically the selector string.
@return [String]
# File lib/sass/selector/sequence.rb, line 172 def inspect members.map {|m| m.inspect}.join(" ") end
Sets the line of the Sass
template on which this selector was declared. This also sets the line for all child selectors.
@param line [Integer] @return [Integer]
# File lib/sass/selector/sequence.rb, line 11 def line=(line) members.each {|m| m.line = line if m.is_a?(SimpleSequence)} @line = line end
Resolves the {Parent} selectors within this selector by replacing them with the given parent selector, handling commas appropriately.
@param super_cseq [CommaSequence] The parent selector @param implicit_parent [Boolean] Whether the the parent
selector should automatically be prepended to the resolved selector if it contains no parent refs.
@return [CommaSequence] This selector, with parent references resolved @raise [Sass::SyntaxError] If a parent selector is invalid
# File lib/sass/selector/sequence.rb, line 52 def resolve_parent_refs(super_cseq, implicit_parent) members = @members.dup nl = (members.first == "\n" && members.shift) contains_parent_ref = contains_parent_ref? return CommaSequence.new([self]) if !implicit_parent && !contains_parent_ref unless contains_parent_ref old_members, members = members, [] members << nl if nl members << SimpleSequence.new([Parent.new], false) members += old_members end CommaSequence.new(Sass::Util.paths(members.map do |sseq_or_op| next [sseq_or_op] unless sseq_or_op.is_a?(SimpleSequence) sseq_or_op.resolve_parent_refs(super_cseq).members end).map do |path| path_members = path.map do |seq_or_op| next seq_or_op unless seq_or_op.is_a?(Sequence) seq_or_op.members end if path_members.length == 2 && path_members[1][0] == "\n" path_members[0].unshift path_members[1].shift end Sequence.new(path_members.flatten) end) end
Converts the subject operator “!”, if it exists, into a “:has()” selector.
@retur [Sequence]
# File lib/sass/selector/sequence.rb, line 189 def subjectless pre_subject = [] has = [] subject = nil members.each do |sseq_or_op| if subject has << sseq_or_op elsif sseq_or_op.is_a?(String) || !sseq_or_op.subject? pre_subject << sseq_or_op else subject = sseq_or_op.dup subject.members = sseq_or_op.members.dup subject.subject = false has = [] end end return self unless subject unless has.empty? subject.members << Pseudo.new(:class, 'has', nil, CommaSequence.new([Sequence.new(has)])) end Sequence.new(pre_subject + [subject]) end
Returns whether or not this selector matches all elements that the given selector matches (as well as possibly more).
@example
(.foo).superselector?(.foo.bar) #=> true (.foo).superselector?(.bar) #=> false
@param cseq [Sequence] @return [Boolean]
# File lib/sass/selector/sequence.rb, line 159 def superselector?(seq) _superselector?(members, seq.members) end
# File lib/sass/selector/sequence.rb, line 164 def to_s(opts = {}) @members.map {|m| m.is_a?(String) ? m : m.to_s(opts)}.join(" ").gsub(/ ?\n ?/, "\n") end
Unifies this with another selector sequence to produce a selector that matches (a subset of) the intersection of the two inputs.
@param other [Sequence] @return [CommaSequence, nil] The unified selector, or nil if unification failed. @raise [Sass::SyntaxError] If this selector cannot be unified.
This will only ever occur when a dynamic selector, such as {Parent} or {Interpolation}, is used in unification. Since these selectors should be resolved by the time extension and unification happen, this exception will only ever be raised as a result of programmer error
# File lib/sass/selector/sequence.rb, line 141 def unify(other) base = members.last other_base = other.members.last return unless base.is_a?(SimpleSequence) && other_base.is_a?(SimpleSequence) return unless (unified = other_base.unify(base)) woven = weave([members[0...-1], other.members[0...-1] + [unified]]) CommaSequence.new(woven.map {|w| Sequence.new(w)}) end
Private Instance Methods
# File lib/sass/selector/sequence.rb, line 623 def _eql?(other) other.members.reject {|m| m == "\n"}.eql?(members.reject {|m| m == "\n"}) end
# File lib/sass/selector/sequence.rb, line 619 def _hash members.reject {|m| m == "\n"}.hash end
# File lib/sass/selector/sequence.rb, line 638 def _sources(seq) s = Set.new seq.map {|sseq_or_op| s.merge sseq_or_op.sources if sseq_or_op.is_a?(SimpleSequence)} s end
Given two selector sequences, returns whether ‘seq1` is a superselector of `seq2`; that is, whether `seq1` matches every element `seq2` matches.
@param seq1 [Array<SimpleSequence or String>] @param seq2 [Array<SimpleSequence or String>] @return [Boolean]
# File lib/sass/selector/sequence.rb, line 489 def _superselector?(seq1, seq2) seq1 = seq1.reject {|e| e == "\n"} seq2 = seq2.reject {|e| e == "\n"} # Selectors with leading or trailing operators are neither # superselectors nor subselectors. return if seq1.last.is_a?(String) || seq2.last.is_a?(String) || seq1.first.is_a?(String) || seq2.first.is_a?(String) # More complex selectors are never superselectors of less complex ones return if seq1.size > seq2.size return seq1.first.superselector?(seq2.last, seq2[0...-1]) if seq1.size == 1 _, si = seq2.each_with_index.find do |e, i| return if i == seq2.size - 1 next if e.is_a?(String) seq1.first.superselector?(e, seq2[0...i]) end return unless si if seq1[1].is_a?(String) return unless seq2[si + 1].is_a?(String) # .foo ~ .bar is a superselector of .foo + .bar return unless seq1[1] == "~" ? seq2[si + 1] != ">" : seq1[1] == seq2[si + 1] # .foo > .baz is not a superselector of .foo > .bar > .baz or .foo > # .bar .baz, despite the fact that .baz is a superselector of .bar > # .baz and .bar .baz. Same goes for + and ~. return if seq1.length == 3 && seq2.length > 3 return _superselector?(seq1[2..-1], seq2[si + 2..-1]) elsif seq2[si + 1].is_a?(String) return unless seq2[si + 1] == ">" return _superselector?(seq1[1..-1], seq2[si + 2..-1]) else return _superselector?(seq1[1..-1], seq2[si + 1..-1]) end end
Takes initial subsequences of ‘seq1` and `seq2` and returns all orderings of those subsequences. The initial subsequences are determined by a block.
Destructively removes the initial subsequences of ‘seq1` and `seq2`.
For example, given ‘(A B C | D E)` and `(1 2 | 3 4 5)` (with `|` denoting the boundary of the initial subsequence), this would return `[(A B C 1 2), (1 2 A B C)]`. The sequences would then be `(D E)` and `(3 4 5)`.
@param seq1 [Array] @param seq2 [Array] @yield [a] Used to determine when to cut off the initial subsequences.
Called repeatedly for each sequence until it returns true.
@yieldparam a [Array] A final subsequence of one input sequence after
cutting off some initial subsequence.
@yieldreturn [Boolean] Whether or not to cut off the initial subsequence
here.
@return [Array<Array>] All possible orderings of the initial subsequences.
# File lib/sass/selector/sequence.rb, line 449 def chunks(seq1, seq2) chunk1 = [] chunk1 << seq1.shift until yield seq1 chunk2 = [] chunk2 << seq2.shift until yield seq2 return [] if chunk1.empty? && chunk2.empty? return [chunk2] if chunk1.empty? return [chunk1] if chunk2.empty? [chunk1 + chunk2, chunk2 + chunk1] end
# File lib/sass/selector/sequence.rb, line 644 def extended_not_expanded_to_s(extended_not_expanded) extended_not_expanded.map do |choices| choices = choices.map do |sel| next sel.first.to_s if sel.size == 1 "#{sel.join ' '}" end next choices.first if choices.size == 1 && !choices.include?(' ') "(#{choices.join ', '})" end.join ' ' end
Groups a sequence into subsequences. The subsequences are determined by strings; adjacent non-string elements will be put into separate groups, but any element adjacent to a string will be grouped with that string.
For example, ‘(A B “C” D E “F” G “H” “I” J)` will become `[(A) (B “C” D) (E “F” G “H” “I” J)]`.
@param seq [Array] @return [Array<Array>]
# File lib/sass/selector/sequence.rb, line 469 def group_selectors(seq) newseq = [] tail = seq.dup until tail.empty? head = [] begin head << tail.shift end while !tail.empty? && head.last.is_a?(String) || tail.first.is_a?(String) newseq << head end newseq end
# File lib/sass/selector/sequence.rb, line 655 def has_root?(sseq) sseq.is_a?(SimpleSequence) && sseq.members.any? {|sel| sel.is_a?(Pseudo) && sel.normalized_name == "root"} end
Extracts final selector combinators (‘“+”`, `“>”`, `“~”`) and the selectors to which they apply from two sequences and merges them together into a single array.
@param seq1 [Array<SimpleSequence or String>] @param seq2 [Array<SimpleSequence or String>] @return [Array<SimpleSequence or String or
Array<Array<SimpleSequence or String>>] If there are no trailing combinators to be merged, this will be the empty array. If the trailing combinators cannot be merged, this will be nil. Otherwise, this will contained the merged selector. Array elements are [Sass::Util#paths]-style options; conceptually, an "or" of multiple selectors.
# File lib/sass/selector/sequence.rb, line 347 def merge_final_ops(seq1, seq2, res = []) ops1, ops2 = [], [] ops1 << seq1.pop while seq1.last.is_a?(String) ops2 << seq2.pop while seq2.last.is_a?(String) # Not worth the headache of trying to preserve newlines here. The most # important use of newlines is at the beginning of the selector to wrap # across lines anyway. ops1.reject! {|o| o == "\n"} ops2.reject! {|o| o == "\n"} return res if ops1.empty? && ops2.empty? if ops1.size > 1 || ops2.size > 1 # If there are multiple operators, something hacky's going on. If one # is a supersequence of the other, use that, otherwise give up. lcs = Sass::Util.lcs(ops1, ops2) return unless lcs == ops1 || lcs == ops2 res.unshift(*(ops1.size > ops2.size ? ops1 : ops2).reverse) return res end # This code looks complicated, but it's actually just a bunch of special # cases for interactions between different combinators. op1, op2 = ops1.first, ops2.first if op1 && op2 sel1 = seq1.pop sel2 = seq2.pop if op1 == '~' && op2 == '~' if sel1.superselector?(sel2) res.unshift sel2, '~' elsif sel2.superselector?(sel1) res.unshift sel1, '~' else merged = sel1.unify(sel2) res.unshift [ [sel1, '~', sel2, '~'], [sel2, '~', sel1, '~'], ([merged, '~'] if merged) ].compact end elsif (op1 == '~' && op2 == '+') || (op1 == '+' && op2 == '~') if op1 == '~' tilde_sel, plus_sel = sel1, sel2 else tilde_sel, plus_sel = sel2, sel1 end if tilde_sel.superselector?(plus_sel) res.unshift plus_sel, '+' else merged = plus_sel.unify(tilde_sel) res.unshift [ [tilde_sel, '~', plus_sel, '+'], ([merged, '+'] if merged) ].compact end elsif op1 == '>' && %w(~ +).include?(op2) res.unshift sel2, op2 seq1.push sel1, op1 elsif op2 == '>' && %w(~ +).include?(op1) res.unshift sel1, op1 seq2.push sel2, op2 elsif op1 == op2 merged = sel1.unify(sel2) return unless merged res.unshift merged, op1 else # Unknown selector combinators can't be unified return end return merge_final_ops(seq1, seq2, res) elsif op1 seq2.pop if op1 == '>' && seq2.last && seq2.last.superselector?(seq1.last) res.unshift seq1.pop, op1 return merge_final_ops(seq1, seq2, res) else # op2 seq1.pop if op2 == '>' && seq1.last && seq1.last.superselector?(seq2.last) res.unshift seq2.pop, op2 return merge_final_ops(seq1, seq2, res) end end
Extracts initial selector combinators (‘“+”`, `“>”`, `“~”`, and `“n”`) from two sequences and merges them together into a single array of selector combinators.
@param seq1 [Array<SimpleSequence or String>] @param seq2 [Array<SimpleSequence or String>] @return [Array<String>, nil] If there are no operators in the merged
sequence, this will be the empty array. If the operators cannot be merged, this will be nil.
# File lib/sass/selector/sequence.rb, line 318 def merge_initial_ops(seq1, seq2) ops1, ops2 = [], [] ops1 << seq1.shift while seq1.first.is_a?(String) ops2 << seq2.shift while seq2.first.is_a?(String) newline = false newline ||= !!ops1.shift if ops1.first == "\n" newline ||= !!ops2.shift if ops2.first == "\n" # If neither sequence is a subsequence of the other, they cannot be # merged successfully lcs = Sass::Util.lcs(ops1, ops2) return unless lcs == ops1 || lcs == ops2 (newline ? ["\n"] : []) + (ops1.size > ops2.size ? ops1 : ops2) end
Returns whether two selectors must be unified to produce a valid combined selector. This is true when both selectors contain the same unique simple selector such as an id.
@param seq1 [Array<SimpleSequence or String>] @param seq2 [Array<SimpleSequence or String>] @return [Boolean]
# File lib/sass/selector/sequence.rb, line 550 def must_unify?(seq1, seq2) unique_selectors = seq1.map do |sseq| next [] if sseq.is_a?(String) sseq.members.select {|sel| sel.unique?} end.flatten.to_set return false if unique_selectors.empty? seq2.any? do |sseq| next false if sseq.is_a?(String) sseq.members.any? do |sel| next unless sel.unique? unique_selectors.include?(sel) end end end
Like {#_superselector?}, but compares the selectors in the context of parent selectors, as though they shared an implicit base simple selector. For example, ‘B` is not normally a superselector of `B A`, since it doesn’t match ‘A` elements. However, it is a parent superselector, since `B X` is a superselector of `B A X`.
@param seq1 [Array<SimpleSequence or String>] @param seq2 [Array<SimpleSequence or String>] @return [Boolean]
# File lib/sass/selector/sequence.rb, line 537 def parent_superselector?(seq1, seq2) base = Sass::Selector::SimpleSequence.new([Sass::Selector::Placeholder.new('<temp>')], false) _superselector?(seq1 + [base], seq2 + [base]) end
# File lib/sass/selector/sequence.rb, line 627 def path_has_two_subjects?(path) subject = false path.each do |sseq_or_op| next unless sseq_or_op.is_a?(SimpleSequence) next unless sseq_or_op.subject? return true if subject subject = true end false end
This interweaves two lists of selectors, returning all possible orderings of them (including using unification) that maintain the relative ordering of the input arrays.
For example, given ‘.foo .bar` and `.baz .bang`, this would return `.foo .bar .baz .bang`, `.foo .bar.baz .bang`, `.foo .baz .bar .bang`, `.foo .baz .bar.bang`, `.foo .baz .bang .bar`, and so on until `.baz .bang .foo .bar`.
Semantically, for selectors A and B, this returns all selectors ‘AB_i` such that the union over all i of elements matched by `AB_i X` is identical to the intersection of all elements matched by `A X` and all elements matched by `B X`. Some `AB_i` are elided to reduce the size of the output.
@param seq1 [Array<SimpleSequence or String>] @param seq2 [Array<SimpleSequence or String>] @return [Array<Array<SimpleSequence or String>>]
# File lib/sass/selector/sequence.rb, line 262 def subweave(seq1, seq2) return [seq2] if seq1.empty? return [seq1] if seq2.empty? seq1, seq2 = seq1.dup, seq2.dup return unless (init = merge_initial_ops(seq1, seq2)) return unless (fin = merge_final_ops(seq1, seq2)) # Make sure there's only one root selector in the output. root1 = has_root?(seq1.first) && seq1.shift root2 = has_root?(seq2.first) && seq2.shift if root1 && root2 return unless (root = root1.unify(root2)) seq1.unshift root seq2.unshift root elsif root1 seq2.unshift root1 elsif root2 seq1.unshift root2 end seq1 = group_selectors(seq1) seq2 = group_selectors(seq2) lcs = Sass::Util.lcs(seq2, seq1) do |s1, s2| next s1 if s1 == s2 next unless s1.first.is_a?(SimpleSequence) && s2.first.is_a?(SimpleSequence) next s2 if parent_superselector?(s1, s2) next s1 if parent_superselector?(s2, s1) next unless must_unify?(s1, s2) next unless (unified = Sequence.new(s1).unify(Sequence.new(s2))) unified.members.first.members if unified.members.length == 1 end diff = [[init]] until lcs.empty? diff << chunks(seq1, seq2) {|s| parent_superselector?(s.first, lcs.first)} << [lcs.shift] seq1.shift seq2.shift end diff << chunks(seq1, seq2) {|s| s.empty?} diff += fin.map {|sel| sel.is_a?(Array) ? sel : [sel]} diff.reject! {|c| c.empty?} Sass::Util.paths(diff).map {|p| p.flatten}.reject {|p| path_has_two_subjects?(p)} end
Removes redundant selectors from between multiple lists of selectors. This takes a list of lists of selector sequences; each individual list is assumed to have no redundancy within itself. A selector is only removed if it’s redundant with a selector in another list.
“Redundant” here means that one selector is a superselector of the other. The more specific selector is removed.
@param seqses [Array<Array<Array<SimpleSequence or String>>>] @return [Array<Array<SimpleSequence or String>>]
# File lib/sass/selector/sequence.rb, line 578 def trim(seqses) # Avoid truly horrific quadratic behavior. TODO: I think there # may be a way to get perfect trimming without going quadratic. return seqses.flatten(1) if seqses.size > 100 # Keep the results in a separate array so we can be sure we aren't # comparing against an already-trimmed selector. This ensures that two # identical selectors don't mutually trim one another. result = seqses.dup # This is n^2 on the sequences, but only comparing between # separate sequences should limit the quadratic behavior. seqses.each_with_index do |seqs1, i| result[i] = seqs1.reject do |seq1| # The maximum specificity of the sources that caused [seq1] to be # generated. In order for [seq1] to be removed, there must be # another selector that's a superselector of it *and* that has # specificity greater or equal to this. max_spec = _sources(seq1).map do |seq| spec = seq.specificity spec.is_a?(Range) ? spec.max : spec end.max || 0 result.any? do |seqs2| next if seqs1.equal?(seqs2) # Second Law of Extend: the specificity of a generated selector # should never be less than the specificity of the extending # selector. # # See https://github.com/nex3/sass/issues/324. seqs2.any? do |seq2| spec2 = _specificity(seq2) spec2 = spec2.begin if spec2.is_a?(Range) spec2 >= max_spec && _superselector?(seq2, seq1) end end end end result.flatten(1) end
Conceptually, this expands “parenthesized selectors”. That is, if we have ‘.A .B {@extend .C}` and `.D .C {…}`, this conceptually expands into `.D .C, .D (.A .B)`, and this function translates `.D (.A .B)` into `.D .A .B, .A .D .B`. For thoroughness, `.A.D .B` would also be required, but including merged selectors results in exponential output for very little gain.
@param path [Array<Array<SimpleSequence or String>>]
A list of parenthesized selector groups.
@return [Array<Array<SimpleSequence or String>>] A list of fully-expanded selectors.
# File lib/sass/selector/sequence.rb, line 226 def weave(path) # This function works by moving through the selector path left-to-right, # building all possible prefixes simultaneously. prefixes = [[]] path.each do |current| next if current.empty? current = current.dup last_current = [current.pop] prefixes = prefixes.map do |prefix| sub = subweave(prefix, current) next [] unless sub sub.map {|seqs| seqs + last_current} end.flatten(1) end prefixes end