Class: REXML::QuickPath

Inherits:
Object show all
Includes:
Functions, XMLTokens
Defined in:
lib/rexml/quickpath.rb

Constant Summary collapse

EMPTY_HASH = 
{}

Constants included from XMLTokens

XMLTokens::NAME, XMLTokens::NAMECHAR, XMLTokens::NAME_STR, XMLTokens::NCNAME_STR, XMLTokens::NMTOKEN, XMLTokens::NMTOKENS, XMLTokens::REFERENCE

Class Method Summary collapse

Methods included from Functions

boolean, ceiling, compare_language, concat, contains, context=, count, false, floor, get_namespace, id, lang, last, local_name, namespace_context, namespace_context=, namespace_uri, normalize_space, not, number, position, processing_instruction, round, starts_with, string, string_length, string_value, substring, substring_after, substring_before, sum, text, translate, true, variables, variables=

Class Method Details

.attribute(name) ⇒ Object 



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# File 'lib/rexml/quickpath.rb', line 206

def QuickPath::attribute( name )
	return Functions.node.attributes[name] if Functions.node.kind_of? Element
end

.axe(elements, axe_name, rest) ⇒ Object 



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# File 'lib/rexml/quickpath.rb', line 106

def QuickPath::axe( elements, axe_name, rest )
	matches = []
	matches = filter( elements.dup, rest ) if axe_name =~ /-or-self$/u
	case axe_name
	when /^descendant/u
		elements.each do |element|
			matches |= filter( element.to_a, "descendant-or-self::#{rest}" ) if element.kind_of? Element
		end
	when /^ancestor/u
		elements.each do |element|
			while element.parent
				matches << element.parent
				element = element.parent
			end
		end
		matches = filter( matches, rest )
	when "self"
		matches = filter( elements, rest )
	when "child"
		elements.each do |element|
			matches |= filter( element.to_a, rest ) if element.kind_of? Element
		end
	when "attribute"
		elements.each do |element|
			matches << element.attributes[ rest ] if element.kind_of? Element
		end
	when "parent"
		matches = filter(elements.collect{|element| element.parent}.uniq, rest)
	when "following-sibling"
		matches = filter(elements.collect{|element| element.next_sibling}.uniq,
			rest)
	when "previous-sibling"
		matches = filter(elements.collect{|element| 
			element.previous_sibling}.uniq, rest )
	end
	return matches.uniq
end

.each(element, path, namespaces = EMPTY_HASH, &block) ⇒ Object 



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# File 'lib/rexml/quickpath.rb', line 15

def QuickPath::each element, path, namespaces=EMPTY_HASH, &block
	path = "*" unless path
	match(element, path, namespaces).each( &block )
end

.filter(elements, path) ⇒ Object

Given an array of nodes it filters the array based on the path. The result is that when this method returns, the array will contain elements which match the path



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# File 'lib/rexml/quickpath.rb', line 48

def QuickPath::filter elements, path
	return elements if path.nil? or path == '' or elements.size == 0
	case path
	when /^\/\//u											# Descendant
		return axe( elements, "descendant-or-self", $' )
	when /^\/?\b(\w[-\w]*)\b::/u							# Axe
		axe_name = $1
		rest = $'
		return axe( elements, $1, $' )
	when /^\/(?=\b([:!\w][-\.\w]*:)?[-!\*\.\w]*\b([^:(]|$)|\*)/u	# Child
		rest = $'
		results = []
		elements.each do |element|
			results |= filter( element.to_a, rest )
		end
		return results
	when /^\/?(\w[-\w]*)\(/u							# / Function
		return function( elements, $1, $' )
	when Namespace::NAMESPLIT		# Element name
		name = $2
		ns = $1
		rest = $'
		elements.delete_if do |element|
			!(element.kind_of? Element and 
				(element.expanded_name == name or
				 (element.name == name and
				  element.namespace == Functions.namespace_context[ns])))
		end
		return filter( elements, rest )
	when /^\/\[/u
		matches = []
		elements.each do |element|
			matches |= predicate( element.to_a, path[1..-1] ) if element.kind_of? Element
		end
		return matches
	when /^\[/u												# Predicate
		return predicate( elements, path )
	when /^\/?\.\.\./u										# Ancestor
		return axe( elements, "ancestor", $' )
	when /^\/?\.\./u											# Parent
		return filter( elements.collect{|e|e.parent}, $' )
	when /^\/?\./u												# Self
		return filter( elements, $' )
	when /^\*/u													# Any
		results = []
		elements.each do |element|
			results |= filter( [element], $' ) if element.kind_of? Element
			#if element.kind_of? Element
			#	children = element.to_a
			#	children.delete_if { |child| !child.kind_of?(Element) }
			#	results |= filter( children, $' )
			#end
		end
		return results
	end
	return []
end

.first(element, path, namespaces = EMPTY_HASH) ⇒ Object 



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# File 'lib/rexml/quickpath.rb', line 11

def QuickPath::first element, path, namespaces=EMPTY_HASH
	match(element, path, namespaces)[0]
end

.function(elements, fname, rest) ⇒ Object 



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# File 'lib/rexml/quickpath.rb', line 222

def QuickPath::function( elements, fname, rest )
	args = parse_args( elements, rest )
	Functions.pair = [0, elements.size]
	results = []
	elements.each do |element|
		Functions.pair[0] += 1
		Functions.node = element
		res = Functions.send( fname, *args )
		case res
		when true
			results << element
		when Fixnum
			results << element if Functions.pair[0] == res
		end
	end
	return results
end

.match(element, path, namespaces = EMPTY_HASH) ⇒ Object 



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# File 'lib/rexml/quickpath.rb', line 20

def QuickPath::match element, path, namespaces=EMPTY_HASH
	raise "nil is not a valid xpath" unless path
	results = nil
	Functions::namespace_context = namespaces
	case path
	when /^\/([^\/]|$)/u
		# match on root
		path = path[1..-1]
		return [element.root.parent] if path == ''
		results = filter([element.root], path)
	when /^[-\w]*::/u
		results = filter([element], path)
	when /^\*/u
		results = filter(element.to_a, path)
	when /^[\[!\w:]/u
		# match on child
		matches = []
		children = element.to_a
		results = filter(children, path)
	else
		results = filter([element], path)
	end
	return results
end

.method_missing(id, *args) ⇒ Object 



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# File 'lib/rexml/quickpath.rb', line 214

def QuickPath::method_missing( id, *args )
	begin
		Functions.send( id.id2name, *args )
	rescue Exception
		raise "METHOD: #{id.id2name}(#{args.join ', '})\n#{$!.message}"
	end
end

.name ⇒ Object 



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# File 'lib/rexml/quickpath.rb', line 210

def QuickPath::name()
	return Functions.node.name if Functions.node.kind_of? Element
end

.parse_args(element, string) ⇒ Object 



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# File 'lib/rexml/quickpath.rb', line 240

def QuickPath::parse_args( element, string )
	# /.*?(?:\)|,)/
	arguments = []
	buffer = ""
	while string and string != ""
		c = string[0]
		string.sub!(/^./u, "")
		case c
		when ?,
			# if depth = 1, then we start a new argument
			arguments << evaluate( buffer )
			#arguments << evaluate( string[0..count] )
		when ?(
			# start a new method call
			function( element, buffer, string )
			buffer = ""
		when ?)
			# close the method call and return arguments
			return arguments
		else
			buffer << c
		end
	end
	""
end

.predicate(elements, path) ⇒ Object

A predicate filters a node-set with respect to an axis to produce a new node-set. For each node in the node-set to be filtered, the PredicateExpr is evaluated with that node as the context node, with the number of nodes in the node-set as the context size, and with the proximity position of the node in the node-set with respect to the axis as the context position; if PredicateExpr evaluates to true for that node, the node is included in the new node-set; otherwise, it is not included.

A PredicateExpr is evaluated by evaluating the Expr and converting the result to a boolean. If the result is a number, the result will be converted to true if the number is equal to the context position and will be converted to false otherwise; if the result is not a number, then the result will be converted as if by a call to the boolean function. Thus a location path para is equivalent to para.



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# File 'lib/rexml/quickpath.rb', line 160

def QuickPath::predicate( elements, path ) 
	ind = 1
	bcount = 1
	while bcount > 0
		bcount += 1 if path[ind] == ?[
		bcount -= 1 if path[ind] == ?]
		ind += 1
	end
	ind -= 1
	predicate = path[1..ind-1]
	rest = path[ind+1..-1]

	# have to change 'a [=<>] b [=<>] c' into 'a [=<>] b and b [=<>] c'
	predicate.gsub!( /([^\s(and)(or)<>=]+)\s*([<>=])\s*([^\s(and)(or)<>=]+)\s*([<>=])\s*([^\s(and)(or)<>=]+)/u ) { 
		"#$1 #$2 #$3 and #$3 #$4 #$5"
	}
	# Let's do some Ruby trickery to avoid some work:
	predicate.gsub!( /&/u, "&&" )
	predicate.gsub!( /=/u, "==" )
	predicate.gsub!( /@(\w[-\w.]*)/u ) {
		"attribute(\"#$1\")" 
	}
	predicate.gsub!( /\bmod\b/u, "%" )
	predicate.gsub!( /\b(\w[-\w.]*\()/u ) {
		fname = $1
		fname.gsub( /-/u, "_" )
	}
	
	Functions.pair = [ 0, elements.size ]
	results = []
	elements.each do |element|
		Functions.pair[0] += 1
		Functions.node = element
		res = eval( predicate )
		case res
		when true
			results << element
		when Fixnum
			results << element if Functions.pair[0] == res
		when String
			results << element
		end
	end
	return filter( results, rest )
end