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!
RelativeLocationPath
| Step | (AXIS_NAME '::' | '@' | '') AxisSpecifier NodeTest Predicate | '.' | '..' AbbreviatedStep | RelativeLocationPath '/' Step | RelativeLocationPath '//' Step
Returns a 1-1 map of the nodeset The contents of the resulting array are either: true/false, if a positive match String, if a name match
NodeTest
| ('*' | NCNAME ':' '*' | QNAME) NameTest | NODE_TYPE '(' ')' NodeType | PI '(' LITERAL ')' PI | '[' expr ']' Predicate
| VARIABLE_REFERENCE | ‘(’ expr ‘)’ | LITERAL | NUMBER | FunctionCall
# File rexml/parsers/xpathparser.rb, line 34
def abbreviate( path )
path = path.kind_of?(String) ? parse( path ) : path
string = ""
document = false
while path.size > 0
op = path.shift
case op
when :node
when :attribute
string << "/" if string.size > 0
string << "@"
when :child
string << "/" if string.size > 0
when :descendant_or_self
string << "/"
when :self
string << "."
when :parent
string << ".."
when :any
string << "*"
when :text
string << "text()"
when :following, :following_sibling,
:ancestor, :ancestor_or_self, :descendant,
:namespace, :preceding, :preceding_sibling
string << "/" unless string.size == 0
string << op.to_s.tr("_", "-")
string << "::"
when :qname
prefix = path.shift
name = path.shift
string << prefix+":" if prefix.size > 0
string << name
when :predicate
string << '['
string << predicate_to_string( path.shift ) {|x| abbreviate( x ) }
string << ']'
when :document
document = true
when :function
string << path.shift
string << "( "
string << predicate_to_string( path.shift[0] ) {|x| abbreviate( x )}
string << " )"
when :literal
string << %{ "#{path.shift}" }
else
string << "/" unless string.size == 0
string << "UNKNOWN("
string << op.inspect
string << ")"
end
end
string = "/"+string if document
return string
end
# File rexml/parsers/xpathparser.rb, line 92
def expand( path )
path = path.kind_of?(String) ? parse( path ) : path
string = ""
document = false
while path.size > 0
op = path.shift
case op
when :node
string << "node()"
when :attribute, :child, :following, :following_sibling,
:ancestor, :ancestor_or_self, :descendant, :descendant_or_self,
:namespace, :preceding, :preceding_sibling, :self, :parent
string << "/" unless string.size == 0
string << op.to_s.tr("_", "-")
string << "::"
when :any
string << "*"
when :qname
prefix = path.shift
name = path.shift
string << prefix+":" if prefix.size > 0
string << name
when :predicate
string << '['
string << predicate_to_string( path.shift ) { |x| expand(x) }
string << ']'
when :document
document = true
else
string << "/" unless string.size == 0
string << "UNKNOWN("
string << op.inspect
string << ")"
end
end
string = "/"+string if document
return string
end
# File rexml/parsers/xpathparser.rb, line 14
def namespaces=( namespaces )
Functions::namespace_context = namespaces
@namespaces = namespaces
end
# File rexml/parsers/xpathparser.rb, line 19
def parse path
path = path.dup
path.gsub!(/([\(\[])\s+/, '\1') # Strip ignorable spaces
path.gsub!( /\s+([\]\)])/, '\1')
parsed = []
path = OrExpr(path, parsed)
parsed
end
# File rexml/parsers/xpathparser.rb, line 28
def predicate path
parsed = []
Predicate( "[#{path}]", parsed )
parsed
end
# File rexml/parsers/xpathparser.rb, line 131
def predicate_to_string( path, &block )
string = ""
case path[0]
when :and, :or, :mult, :plus, :minus, :neq, :eq, :lt, :gt, :lteq, :gteq, :div, :mod, :union
op = path.shift
case op
when :eq
op = "="
when :lt
op = "<"
when :gt
op = ">"
when :lteq
op = "<="
when :gteq
op = ">="
when :neq
op = "!="
when :union
op = "|"
end
left = predicate_to_string( path.shift, &block )
right = predicate_to_string( path.shift, &block )
string << " "
string << left
string << " "
string << op.to_s
string << " "
string << right
string << " "
when :function
path.shift
name = path.shift
string << name
string << "( "
string << predicate_to_string( path.shift, &block )
string << " )"
when :literal
path.shift
string << " "
string << path.shift.inspect
string << " "
else
string << " "
string << yield( path )
string << " "
end
return string.squeeze(" ")
end