Class
You don’t want to use this class. Really. Use XPath, which is a wrapper for this class. Believe me. You don’t want to poke around in here. There is strange, dark magic at work in this code. Beware. Go back! Go back while you still can!
Constants
No documentation available
Expr takes a stack of path elements and a set of nodes (either a Parent or an Array and returns an Array of matching nodes
No documentation available
Class Methods
::
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 50
def initialize( )
@parser = REXML::Parsers::XPathParser.new
@namespaces = nil
@variables = {}
end
No documentation available
Instance Methods
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 81
def []=( variable_name, value )
@variables[ variable_name ] = value
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 681
def compare a, op, b
case op
when :eq
a == b
when :neq
a != b
when :lt
a < b
when :lteq
a <= b
when :gt
a > b
when :gteq
a >= b
when :and
a and b
when :or
a or b
else
false
end
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 477
def d_o_s( p, ns, r )
nt = nil
ns.each_index do |i|
n = ns[i]
x = expr( p.dclone, [ n ] )
nt = n.node_type
d_o_s( p, n.children, x ) if nt == :element or nt == :document and n.children.size > 0
r.concat(x) if x.size > 0
end
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 470
def descendant_or_self( path_stack, nodeset )
rs = []
d_o_s( path_stack, nodeset, rs )
document_order(rs.flatten.compact)
#rs.flatten.compact
end
FIXME The next two methods are BAD MOJO! This is my achilles heel. If anybody thinks of a better way of doing this, be my guest. This really sucks, but it is a wonder it works at all. ########################################################
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 497
def document_order( array_of_nodes )
new_arry = []
array_of_nodes.each { |node|
node_idx = []
np = node.node_type == :attribute ? node.element : node
while np.parent and np.parent.node_type == :element
node_idx << np.parent.index( np )
np = np.parent
end
new_arry << [ node_idx.reverse, node ]
}
new_arry.sort{ |s1, s2| s1[0] <=> s2[0] }.collect{ |s| s[1] }
end
Reorders an array of nodes so that they are in document order It tries to do this efficiently.
FIXME: I need to get rid of this, but the issue is that most of the XPath interpreter functions as a filter, which means that we lose context going in and out of function calls. If I knew what the index of the nodes was, I wouldn’t have to do this. Maybe add a document IDX for each node? Problems with mutable documents. Or, rewrite everything.
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 603
def equality_relational_compare( set1, op, set2 )
if set1.kind_of? Array and set2.kind_of? Array
if set1.size == 1 and set2.size == 1
set1 = set1[0]
set2 = set2[0]
elsif set1.size == 0 or set2.size == 0
nd = set1.size==0 ? set2 : set1
rv = nd.collect { |il| compare( il, op, nil ) }
return rv
else
res = []
SyncEnumerator.new( set1, set2 ).each { |i1, i2|
i1 = norm( i1 )
i2 = norm( i2 )
res << compare( i1, op, i2 )
}
return res
end
end
# If one is nodeset and other is number, compare number to each item
# in nodeset s.t. number op number(string(item))
# If one is nodeset and other is string, compare string to each item
# in nodeset s.t. string op string(item)
# If one is nodeset and other is boolean, compare boolean to each item
# in nodeset s.t. boolean op boolean(item)
if set1.kind_of? Array or set2.kind_of? Array
if set1.kind_of? Array
a = set1
b = set2
else
a = set2
b = set1
end
case b
when true, false
return a.collect {|v| compare( Functions::boolean(v), op, b ) }
when Numeric
return a.collect {|v| compare( Functions::number(v), op, b )}
when /^\d+(\.\d+)?$/
b = Functions::number( b )
return a.collect {|v| compare( Functions::number(v), op, b )}
else
b = Functions::string( b )
return a.collect { |v| compare( Functions::string(v), op, b ) }
end
else
# If neither is nodeset,
# If op is = or !=
# If either boolean, convert to boolean
# If either number, convert to number
# Else, convert to string
# Else
# Convert both to numbers and compare
s1 = set1.to_s
s2 = set2.to_s
if s1 == 'true' or s1 == 'false' or s2 == 'true' or s2 == 'false'
set1 = Functions::boolean( set1 )
set2 = Functions::boolean( set2 )
else
if op == :eq or op == :neq
if s1 =~ /^\d+(\.\d+)?$/ or s2 =~ /^\d+(\.\d+)?$/
set1 = Functions::number( s1 )
set2 = Functions::number( s2 )
else
set1 = Functions::string( set1 )
set2 = Functions::string( set2 )
end
else
set1 = Functions::number( set1 )
set2 = Functions::number( set2 )
end
end
return compare( set1, op, set2 )
end
return false
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 153
def expr( path_stack, nodeset, context=nil )
node_types = ELEMENTS
return nodeset if path_stack.length == 0 || nodeset.length == 0
while path_stack.length > 0
if nodeset.length == 0
path_stack.clear
return []
end
case (op = path_stack.shift)
when :document
nodeset = [ nodeset[0].root_node ]
when :qname
prefix = path_stack.shift
name = path_stack.shift
nodeset.delete_if do |node|
# FIXME: This DOUBLES the time XPath searches take
ns = get_namespace( node, prefix )
if node.node_type == :element
if node.name == name
end
end
!(node.node_type == :element and
node.name == name and
node.namespace == ns )
end
node_types = ELEMENTS
when :any
nodeset.delete_if { |node| !node_types.include?(node.node_type) }
when :self
# This space left intentionally blank
when :processing_instruction
target = path_stack.shift
nodeset.delete_if do |node|
(node.node_type != :processing_instruction) or
( target!='' and ( node.target != target ) )
end
when :text
nodeset.delete_if { |node| node.node_type != :text }
when :comment
nodeset.delete_if { |node| node.node_type != :comment }
when :node
# This space left intentionally blank
node_types = ALL
when :child
new_nodeset = []
nt = nil
nodeset.each do |node|
nt = node.node_type
new_nodeset += node.children if nt == :element or nt == :document
end
nodeset = new_nodeset
node_types = ELEMENTS
when :literal
return path_stack.shift
when :attribute
new_nodeset = []
case path_stack.shift
when :qname
prefix = path_stack.shift
name = path_stack.shift
for element in nodeset
if element.node_type == :element
attrib = element.attribute( name, get_namespace(element, prefix) )
new_nodeset << attrib if attrib
end
end
when :any
for element in nodeset
if element.node_type == :element
new_nodeset += element.attributes.to_a
end
end
end
nodeset = new_nodeset
when :parent
nodeset = nodeset.collect{|n| n.parent}.compact
#nodeset = expr(path_stack.dclone, nodeset.collect{|n| n.parent}.compact)
node_types = ELEMENTS
when :ancestor
new_nodeset = []
nodeset.each do |node|
while node.parent
node = node.parent
new_nodeset << node unless new_nodeset.include? node
end
end
nodeset = new_nodeset
node_types = ELEMENTS
when :ancestor_or_self
new_nodeset = []
nodeset.each do |node|
if node.node_type == :element
new_nodeset << node
while ( node.parent )
node = node.parent
new_nodeset << node unless new_nodeset.include? node
end
end
end
nodeset = new_nodeset
node_types = ELEMENTS
when :predicate
new_nodeset = []
subcontext = { :size => nodeset.size }
pred = path_stack.shift
nodeset.each_with_index { |node, index|
subcontext[ :node ] = node
subcontext[ :index ] = index+1
pc = pred.dclone
result = expr( pc, [node], subcontext )
result = result[0] if result.kind_of? Array and result.length == 1
if result.kind_of? Numeric
new_nodeset << node if result == (index+1)
elsif result.instance_of? Array
if result.size > 0 and result.inject(false) {|k,s| s or k}
new_nodeset << node if result.size > 0
end
else
new_nodeset << node if result
end
}
nodeset = new_nodeset
=begin
predicate = path_stack.shift
ns = nodeset.clone
result = expr( predicate, ns )
if result.kind_of? Array
nodeset = result.zip(ns).collect{|m,n| n if m}.compact
else
nodeset = result ? nodeset : []
end
=end
when :descendant_or_self
rv = descendant_or_self( path_stack, nodeset )
path_stack.clear
nodeset = rv
node_types = ELEMENTS
when :descendant
results = []
nt = nil
nodeset.each do |node|
nt = node.node_type
results += expr( path_stack.dclone.unshift( :descendant_or_self ),
node.children ) if nt == :element or nt == :document
end
nodeset = results
node_types = ELEMENTS
when :following_sibling
results = []
nodeset.each do |node|
next if node.parent.nil?
all_siblings = node.parent.children
current_index = all_siblings.index( node )
following_siblings = all_siblings[ current_index+1 .. -1 ]
results += expr( path_stack.dclone, following_siblings )
end
nodeset = results
when :preceding_sibling
results = []
nodeset.each do |node|
next if node.parent.nil?
all_siblings = node.parent.children
current_index = all_siblings.index( node )
preceding_siblings = all_siblings[ 0, current_index ].reverse
results += preceding_siblings
end
nodeset = results
node_types = ELEMENTS
when :preceding
new_nodeset = []
nodeset.each do |node|
new_nodeset += preceding( node )
end
nodeset = new_nodeset
node_types = ELEMENTS
when :following
new_nodeset = []
nodeset.each do |node|
new_nodeset += following( node )
end
nodeset = new_nodeset
node_types = ELEMENTS
when :namespace
new_nodeset = []
prefix = path_stack.shift
nodeset.each do |node|
if (node.node_type == :element or node.node_type == :attribute)
if @namespaces
namespaces = @namespaces
elsif (node.node_type == :element)
namespaces = node.namespaces
else
namespaces = node.element.namesapces
end
if (node.namespace == namespaces[prefix])
new_nodeset << node
end
end
end
nodeset = new_nodeset
when :variable
var_name = path_stack.shift
return @variables[ var_name ]
# :and, :or, :eq, :neq, :lt, :lteq, :gt, :gteq
# TODO: Special case for :or and :and -- not evaluate the right
# operand if the left alone determines result (i.e. is true for
# :or and false for :and).
when :eq, :neq, :lt, :lteq, :gt, :gteq, :or
left = expr( path_stack.shift, nodeset.dup, context )
right = expr( path_stack.shift, nodeset.dup, context )
res = equality_relational_compare( left, op, right )
return res
when :and
left = expr( path_stack.shift, nodeset.dup, context )
return [] unless left
if left.respond_to?(:inject) and !left.inject(false) {|a,b| a | b}
return []
end
right = expr( path_stack.shift, nodeset.dup, context )
res = equality_relational_compare( left, op, right )
return res
when :div
left = Functions::number(expr(path_stack.shift, nodeset, context)).to_f
right = Functions::number(expr(path_stack.shift, nodeset, context)).to_f
return (left / right)
when :mod
left = Functions::number(expr(path_stack.shift, nodeset, context )).to_f
right = Functions::number(expr(path_stack.shift, nodeset, context )).to_f
return (left % right)
when :mult
left = Functions::number(expr(path_stack.shift, nodeset, context )).to_f
right = Functions::number(expr(path_stack.shift, nodeset, context )).to_f
return (left * right)
when :plus
left = Functions::number(expr(path_stack.shift, nodeset, context )).to_f
right = Functions::number(expr(path_stack.shift, nodeset, context )).to_f
return (left + right)
when :minus
left = Functions::number(expr(path_stack.shift, nodeset, context )).to_f
right = Functions::number(expr(path_stack.shift, nodeset, context )).to_f
return (left - right)
when :union
left = expr( path_stack.shift, nodeset, context )
right = expr( path_stack.shift, nodeset, context )
return (left | right)
when :neg
res = expr( path_stack, nodeset, context )
return -(res.to_f)
when :not
when :function
func_name = path_stack.shift.tr('-','_')
arguments = path_stack.shift
subcontext = context ? nil : { :size => nodeset.size }
res = []
cont = context
nodeset.each_with_index { |n, i|
if subcontext
subcontext[:node] = n
subcontext[:index] = i
cont = subcontext
end
arg_clone = arguments.dclone
args = arg_clone.collect { |arg|
expr( arg, [n], cont )
}
Functions.context = cont
res << Functions.send( func_name, *args )
}
return res
end
end # while
return nodeset
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 90
def first( path_stack, node )
return nil if path.size == 0
case path[0]
when :document
# do nothing
return first( path[1..-1], node )
when :child
for c in node.children
r = first( path[1..-1], c )
return r if r
end
when :qname
name = path[2]
if node.name == name
return node if path.size == 3
return first( path[3..-1], node )
else
return nil
end
when :descendant_or_self
r = first( path[1..-1], node )
return r if r
for c in node.children
r = first( path, c )
return r if r
end
when :node
return first( path[1..-1], node )
when :any
return first( path[1..-1], node )
end
return nil
end
Performs a depth-first (document order) XPath search, and returns the first match. This is the fastest, lightest way to return a single result.
FIXME: This method is incomplete!
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 561
def following( node )
acc = []
p = next_sibling_node( node )
while p
acc << p
p = following_node_of( p )
end
acc
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 571
def following_node_of( node )
if node.kind_of? Element and node.children.size > 0
return node.children[0]
end
return next_sibling_node(node)
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 71
def get_first path, nodeset
path_stack = @parser.parse( path )
first( path_stack, nodeset )
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 139
def get_namespace( node, prefix )
if @namespaces
return @namespaces[prefix] || ''
else
return node.namespace( prefix ) if node.node_type == :element
return ''
end
end
Returns a String namespace for a node, given a prefix The rules are:
1. Use the supplied namespace mapping first. 2. If no mapping was supplied, use the context node to look up the namespace
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 126
def match( path_stack, nodeset )
r = expr( path_stack, nodeset )
r
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 56
def namespaces=( namespaces={} )
Functions::namespace_context = namespaces
@namespaces = namespaces
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 578
def next_sibling_node(node)
psn = node.next_sibling_node
while psn.nil?
if node.parent.nil? or node.parent.class == Document
return nil
end
node = node.parent
psn = node.next_sibling_node
end
return psn
end
No documentation available
#
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 590
def norm b
case b
when true, false
return b
when 'true', 'false'
return Functions::boolean( b )
when /^\d+(\.\d+)?$/
return Functions::number( b )
else
return Functions::string( b )
end
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 66
def parse path, nodeset
path_stack = @parser.parse( path )
match( path_stack, nodeset )
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 525
def preceding( node )
ancestors = []
p = node.parent
while p
ancestors << p
p = p.parent
end
acc = []
p = preceding_node_of( node )
while p
if ancestors.include? p
ancestors.delete(p)
else
acc << p
end
p = preceding_node_of( p )
end
acc
end
Builds a nodeset of all of the preceding nodes of the supplied node, in reverse document order
- preceding
-
includes every element in the document that precedes this node,
except for ancestors
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 546
def preceding_node_of( node )
psn = node.previous_sibling_node
if psn.nil?
if node.parent.nil? or node.parent.class == Document
return nil
end
return node.parent
#psn = preceding_node_of( node.parent )
end
while psn and psn.kind_of? Element and psn.children.size > 0
psn = psn.children[-1]
end
psn
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 76
def predicate path, nodeset
path_stack = @parser.parse( path )
expr( path_stack, nodeset )
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 512
def recurse( nodeset, &block )
for node in nodeset
yield node
recurse( node, &block ) if node.node_type == :element
end
end
No documentation available
lib/rexml/xpath_parser.rb
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# File tmp/rubies/ruby-2.3.8/lib/rexml/xpath_parser.rb, line 61
def variables=( vars={} )
Functions::variables = vars
@variables = vars
end
No documentation available