263 lines
7.6 KiB
Ruby
263 lines
7.6 KiB
Ruby
require 'rexml/functions'
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require 'rexml/xmltokens'
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module REXML
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class QuickPath
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include Functions
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include XMLTokens
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EMPTY_HASH = {}
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def QuickPath::first element, path, namespaces=EMPTY_HASH
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match(element, path, namespaces)[0]
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end
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def QuickPath::each element, path, namespaces=EMPTY_HASH, &block
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path = "*" unless path
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match(element, path, namespaces).each( &block )
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end
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def QuickPath::match element, path, namespaces=EMPTY_HASH
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raise "nil is not a valid xpath" unless path
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results = nil
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Functions::namespace_context = namespaces
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case path
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when /^\/([^\/]|$)/u
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# match on root
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path = path[1..-1]
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return [element.root.parent] if path == ''
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results = filter([element.root], path)
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when /^[-\w]*::/u
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results = filter([element], path)
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when /^\*/u
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results = filter(element.to_a, path)
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when /^[\[!\w:]/u
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# match on child
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matches = []
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children = element.to_a
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results = filter(children, path)
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else
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results = filter([element], path)
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end
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return results
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end
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# Given an array of nodes it filters the array based on the path. The
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# result is that when this method returns, the array will contain elements
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# which match the path
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def QuickPath::filter elements, path
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return elements if path.nil? or path == '' or elements.size == 0
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case path
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when /^\/\//u # Descendant
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return axe( elements, "descendant-or-self", $' )
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when /^\/?\b(\w[-\w]*)\b::/u # Axe
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axe_name = $1
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rest = $'
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return axe( elements, $1, $' )
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when /^\/(?=\b([:!\w][-\.\w]*:)?[-!\*\.\w]*\b([^:(]|$)|\*)/u # Child
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rest = $'
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results = []
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elements.each do |element|
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results |= filter( element.to_a, rest )
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end
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return results
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when /^\/?(\w[-\w]*)\(/u # / Function
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return function( elements, $1, $' )
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when Namespace::NAMESPLIT # Element name
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name = $2
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ns = $1
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rest = $'
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elements.delete_if do |element|
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!(element.kind_of? Element and
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(element.expanded_name == name or
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(element.name == name and
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element.namespace == Functions.namespace_context[ns])))
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end
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return filter( elements, rest )
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when /^\/\[/u
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matches = []
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elements.each do |element|
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matches |= predicate( element.to_a, path[1..-1] ) if element.kind_of? Element
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end
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return matches
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when /^\[/u # Predicate
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return predicate( elements, path )
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when /^\/?\.\.\./u # Ancestor
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return axe( elements, "ancestor", $' )
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when /^\/?\.\./u # Parent
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return filter( elements.collect{|e|e.parent}, $' )
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when /^\/?\./u # Self
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return filter( elements, $' )
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when /^\*/u # Any
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results = []
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elements.each do |element|
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results |= filter( [element], $' ) if element.kind_of? Element
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#if element.kind_of? Element
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# children = element.to_a
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# children.delete_if { |child| !child.kind_of?(Element) }
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# results |= filter( children, $' )
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#end
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end
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return results
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end
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return []
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end
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def QuickPath::axe( elements, axe_name, rest )
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matches = []
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matches = filter( elements.dup, rest ) if axe_name =~ /-or-self$/u
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case axe_name
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when /^descendant/u
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elements.each do |element|
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matches |= filter( element.to_a, "descendant-or-self::#{rest}" ) if element.kind_of? Element
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end
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when /^ancestor/u
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elements.each do |element|
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while element.parent
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matches << element.parent
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element = element.parent
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end
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end
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matches = filter( matches, rest )
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when "self"
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matches = filter( elements, rest )
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when "child"
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elements.each do |element|
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matches |= filter( element.to_a, rest ) if element.kind_of? Element
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end
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when "attribute"
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elements.each do |element|
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matches << element.attributes[ rest ] if element.kind_of? Element
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end
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when "parent"
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matches = filter(elements.collect{|element| element.parent}.uniq, rest)
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when "following-sibling"
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matches = filter(elements.collect{|element| element.next_sibling}.uniq,
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rest)
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when "previous-sibling"
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matches = filter(elements.collect{|element|
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element.previous_sibling}.uniq, rest )
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end
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return matches.uniq
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end
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# A predicate filters a node-set with respect to an axis to produce a
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# new node-set. For each node in the node-set to be filtered, the
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# PredicateExpr is evaluated with that node as the context node, with
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# the number of nodes in the node-set as the context size, and with the
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# proximity position of the node in the node-set with respect to the
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# axis as the context position; if PredicateExpr evaluates to true for
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# that node, the node is included in the new node-set; otherwise, it is
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# not included.
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#
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# A PredicateExpr is evaluated by evaluating the Expr and converting
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# the result to a boolean. If the result is a number, the result will
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# be converted to true if the number is equal to the context position
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# and will be converted to false otherwise; if the result is not a
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# number, then the result will be converted as if by a call to the
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# boolean function. Thus a location path para[3] is equivalent to
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# para[position()=3].
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def QuickPath::predicate( elements, path )
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ind = 1
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bcount = 1
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while bcount > 0
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bcount += 1 if path[ind] == ?[
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bcount -= 1 if path[ind] == ?]
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ind += 1
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end
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ind -= 1
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predicate = path[1..ind-1]
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rest = path[ind+1..-1]
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# have to change 'a [=<>] b [=<>] c' into 'a [=<>] b and b [=<>] c'
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predicate.gsub!( /([^\s(and)(or)<>=]+)\s*([<>=])\s*([^\s(and)(or)<>=]+)\s*([<>=])\s*([^\s(and)(or)<>=]+)/u,
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'\1 \2 \3 and \3 \4 \5' )
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# Let's do some Ruby trickery to avoid some work:
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predicate.gsub!( /&/u, "&&" )
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predicate.gsub!( /=/u, "==" )
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predicate.gsub!( /@(\w[-\w.]*)/u, 'attribute("\1")' )
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predicate.gsub!( /\bmod\b/u, "%" )
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predicate.gsub!( /\b(\w[-\w.]*\()/u ) {
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fname = $1
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fname.gsub( /-/u, "_" )
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}
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Functions.pair = [ 0, elements.size ]
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results = []
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elements.each do |element|
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Functions.pair[0] += 1
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Functions.node = element
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res = eval( predicate )
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case res
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when true
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results << element
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when Fixnum
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results << element if Functions.pair[0] == res
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when String
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results << element
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end
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end
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return filter( results, rest )
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end
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def QuickPath::attribute( name )
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return Functions.node.attributes[name] if Functions.node.kind_of? Element
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end
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def QuickPath::name()
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return Functions.node.name if Functions.node.kind_of? Element
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end
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def QuickPath::method_missing( id, *args )
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begin
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Functions.send( id.id2name, *args )
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rescue Exception
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raise "METHOD: #{id.id2name}(#{args.join ', '})\n#{$!.message}"
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end
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end
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def QuickPath::function( elements, fname, rest )
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args = parse_args( elements, rest )
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Functions.pair = [0, elements.size]
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results = []
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elements.each do |element|
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Functions.pair[0] += 1
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Functions.node = element
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res = Functions.send( fname, *args )
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case res
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when true
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results << element
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when Fixnum
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results << element if Functions.pair[0] == res
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end
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end
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return results
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end
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def QuickPath::parse_args( element, string )
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# /.*?(?:\)|,)/
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arguments = []
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buffer = ""
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while string and string != ""
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c = string[0]
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string.sub!(/^./u, "")
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case c
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when ?,
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# if depth = 1, then we start a new argument
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arguments << evaluate( buffer )
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#arguments << evaluate( string[0..count] )
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when ?(
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# start a new method call
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function( element, buffer, string )
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buffer = ""
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when ?)
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# close the method call and return arguments
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return arguments
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else
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buffer << c
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end
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end
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""
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end
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end
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end
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