Mini Shell
require 'rexml/namespace'
require 'rexml/xmltokens'
module REXML
module Parsers
# 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!
class XPathParser
include XMLTokens
LITERAL = /^'([^']*)'|^"([^"]*)"/u
def namespaces=( namespaces )
Functions::namespace_context = namespaces
@namespaces = namespaces
end
def parse path
path = path.dup
path.gsub!(/([\(\[])\s+/, '\1') # Strip ignorable spaces
path.gsub!( /\s+([\]\)])/, '\1')
parsed = []
path = OrExpr(path, parsed)
parsed
end
def predicate path
parsed = []
Predicate( "[#{path}]", parsed )
parsed
end
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 << %Q{ "#{path.shift}" }
else
string << "/" unless string.size == 0
string << "UNKNOWN("
string << op.inspect
string << ")"
end
end
string = "/"+string if document
return string
end
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
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
private
#LocationPath
# | RelativeLocationPath
# | '/' RelativeLocationPath?
# | '//' RelativeLocationPath
def LocationPath path, parsed
#puts "LocationPath '#{path}'"
path = path.strip
if path[0] == ?/
parsed << :document
if path[1] == ?/
parsed << :descendant_or_self
parsed << :node
path = path[2..-1]
else
path = path[1..-1]
end
end
#puts parsed.inspect
return RelativeLocationPath( path, parsed ) if path.size > 0
end
#RelativeLocationPath
# | Step
# | (AXIS_NAME '::' | '@' | '') AxisSpecifier
# NodeTest
# Predicate
# | '.' | '..' AbbreviatedStep
# | RelativeLocationPath '/' Step
# | RelativeLocationPath '//' Step
AXIS = /^(ancestor|ancestor-or-self|attribute|child|descendant|descendant-or-self|following|following-sibling|namespace|parent|preceding|preceding-sibling|self)::/
def RelativeLocationPath path, parsed
#puts "RelativeLocationPath #{path}"
while path.size > 0
# (axis or @ or <child::>) nodetest predicate >
# OR > / Step
# (. or ..) >
if path[0] == ?.
if path[1] == ?.
parsed << :parent
parsed << :node
path = path[2..-1]
else
parsed << :self
parsed << :node
path = path[1..-1]
end
else
if path[0] == ?@
#puts "ATTRIBUTE"
parsed << :attribute
path = path[1..-1]
# Goto Nodetest
elsif path =~ AXIS
parsed << $1.tr('-','_').intern
path = $'
# Goto Nodetest
else
parsed << :child
end
#puts "NODETESTING '#{path}'"
n = []
path = NodeTest( path, n)
#puts "NODETEST RETURNED '#{path}'"
if path[0] == ?[
path = Predicate( path, n )
end
parsed.concat(n)
end
if path.size > 0
if path[0] == ?/
if path[1] == ?/
parsed << :descendant_or_self
parsed << :node
path = path[2..-1]
else
path = path[1..-1]
end
else
return path
end
end
end
return path
end
# 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
NCNAMETEST= /^(#{NCNAME_STR}):\*/u
QNAME = Namespace::NAMESPLIT
NODE_TYPE = /^(comment|text|node)\(\s*\)/m
PI = /^processing-instruction\(/
def NodeTest path, parsed
#puts "NodeTest with #{path}"
case path
when /^\*/
path = $'
parsed << :any
when NODE_TYPE
type = $1
path = $'
parsed << type.tr('-', '_').intern
when PI
path = $'
literal = nil
if path !~ /^\s*\)/
path =~ LITERAL
literal = $1
path = $'
raise ParseException.new("Missing ')' after processing instruction") if path[0] != ?)
path = path[1..-1]
end
parsed << :processing_instruction
parsed << (literal || '')
when NCNAMETEST
#puts "NCNAMETEST"
prefix = $1
path = $'
parsed << :namespace
parsed << prefix
when QNAME
#puts "QNAME"
prefix = $1
name = $2
path = $'
prefix = "" unless prefix
parsed << :qname
parsed << prefix
parsed << name
end
return path
end
# Filters the supplied nodeset on the predicate(s)
def Predicate path, parsed
#puts "PREDICATE with #{path}"
return nil unless path[0] == ?[
predicates = []
while path[0] == ?[
path, expr = get_group(path)
predicates << expr[1..-2] if expr
end
#puts "PREDICATES = #{predicates.inspect}"
predicates.each{ |pred|
#puts "ORING #{pred}"
preds = []
parsed << :predicate
parsed << preds
OrExpr(pred, preds)
}
#puts "PREDICATES = #{predicates.inspect}"
path
end
# The following return arrays of true/false, a 1-1 mapping of the
# supplied nodeset, except for axe(), which returns a filtered
# nodeset
#| OrExpr S 'or' S AndExpr
#| AndExpr
def OrExpr path, parsed
#puts "OR >>> #{path}"
n = []
rest = AndExpr( path, n )
#puts "OR <<< #{rest}"
if rest != path
while rest =~ /^\s*( or )/
n = [ :or, n, [] ]
rest = AndExpr( $', n[-1] )
end
end
if parsed.size == 0 and n.size != 0
parsed.replace(n)
elsif n.size > 0
parsed << n
end
rest
end
#| AndExpr S 'and' S EqualityExpr
#| EqualityExpr
def AndExpr path, parsed
#puts "AND >>> #{path}"
n = []
rest = EqualityExpr( path, n )
#puts "AND <<< #{rest}"
if rest != path
while rest =~ /^\s*( and )/
n = [ :and, n, [] ]
#puts "AND >>> #{rest}"
rest = EqualityExpr( $', n[-1] )
#puts "AND <<< #{rest}"
end
end
if parsed.size == 0 and n.size != 0
parsed.replace(n)
elsif n.size > 0
parsed << n
end
rest
end
#| EqualityExpr ('=' | '!=') RelationalExpr
#| RelationalExpr
def EqualityExpr path, parsed
#puts "EQUALITY >>> #{path}"
n = []
rest = RelationalExpr( path, n )
#puts "EQUALITY <<< #{rest}"
if rest != path
while rest =~ /^\s*(!?=)\s*/
if $1[0] == ?!
n = [ :neq, n, [] ]
else
n = [ :eq, n, [] ]
end
rest = RelationalExpr( $', n[-1] )
end
end
if parsed.size == 0 and n.size != 0
parsed.replace(n)
elsif n.size > 0
parsed << n
end
rest
end
#| RelationalExpr ('<' | '>' | '<=' | '>=') AdditiveExpr
#| AdditiveExpr
def RelationalExpr path, parsed
#puts "RELATION >>> #{path}"
n = []
rest = AdditiveExpr( path, n )
#puts "RELATION <<< #{rest}"
if rest != path
while rest =~ /^\s*([<>]=?)\s*/
if $1[0] == ?<
sym = "lt"
else
sym = "gt"
end
sym << "eq" if $1[-1] == ?=
n = [ sym.intern, n, [] ]
rest = AdditiveExpr( $', n[-1] )
end
end
if parsed.size == 0 and n.size != 0
parsed.replace(n)
elsif n.size > 0
parsed << n
end
rest
end
#| AdditiveExpr ('+' | S '-') MultiplicativeExpr
#| MultiplicativeExpr
def AdditiveExpr path, parsed
#puts "ADDITIVE >>> #{path}"
n = []
rest = MultiplicativeExpr( path, n )
#puts "ADDITIVE <<< #{rest}"
if rest != path
while rest =~ /^\s*(\+| -)\s*/
if $1[0] == ?+
n = [ :plus, n, [] ]
else
n = [ :minus, n, [] ]
end
rest = MultiplicativeExpr( $', n[-1] )
end
end
if parsed.size == 0 and n.size != 0
parsed.replace(n)
elsif n.size > 0
parsed << n
end
rest
end
#| MultiplicativeExpr ('*' | S ('div' | 'mod') S) UnaryExpr
#| UnaryExpr
def MultiplicativeExpr path, parsed
#puts "MULT >>> #{path}"
n = []
rest = UnaryExpr( path, n )
#puts "MULT <<< #{rest}"
if rest != path
while rest =~ /^\s*(\*| div | mod )\s*/
if $1[0] == ?*
n = [ :mult, n, [] ]
elsif $1.include?( "div" )
n = [ :div, n, [] ]
else
n = [ :mod, n, [] ]
end
rest = UnaryExpr( $', n[-1] )
end
end
if parsed.size == 0 and n.size != 0
parsed.replace(n)
elsif n.size > 0
parsed << n
end
rest
end
#| '-' UnaryExpr
#| UnionExpr
def UnaryExpr path, parsed
path =~ /^(\-*)/
path = $'
if $1 and (($1.size % 2) != 0)
mult = -1
else
mult = 1
end
parsed << :neg if mult < 0
#puts "UNARY >>> #{path}"
n = []
path = UnionExpr( path, n )
#puts "UNARY <<< #{path}"
parsed.concat( n )
path
end
#| UnionExpr '|' PathExpr
#| PathExpr
def UnionExpr path, parsed
#puts "UNION >>> #{path}"
n = []
rest = PathExpr( path, n )
#puts "UNION <<< #{rest}"
if rest != path
while rest =~ /^\s*(\|)\s*/
n = [ :union, n, [] ]
rest = PathExpr( $', n[-1] )
end
end
if parsed.size == 0 and n.size != 0
parsed.replace( n )
elsif n.size > 0
parsed << n
end
rest
end
#| LocationPath
#| FilterExpr ('/' | '//') RelativeLocationPath
def PathExpr path, parsed
path =~ /^\s*/
path = $'
#puts "PATH >>> #{path}"
n = []
rest = FilterExpr( path, n )
#puts "PATH <<< '#{rest}'"
if rest != path
if rest and rest[0] == ?/
return RelativeLocationPath(rest, n)
end
end
#puts "BEFORE WITH '#{rest}'"
rest = LocationPath(rest, n) if rest =~ /\A[\/\.\@\[\w*]/
parsed.concat(n)
return rest
end
#| FilterExpr Predicate
#| PrimaryExpr
def FilterExpr path, parsed
#puts "FILTER >>> #{path}"
n = []
path = PrimaryExpr( path, n )
#puts "FILTER <<< #{path}"
path = Predicate(path, n) if path and path[0] == ?[
#puts "FILTER <<< #{path}"
parsed.concat(n)
path
end
#| VARIABLE_REFERENCE
#| '(' expr ')'
#| LITERAL
#| NUMBER
#| FunctionCall
VARIABLE_REFERENCE = /^\$(#{NAME_STR})/u
NUMBER = /^(\d*\.?\d+)/
NT = /^comment|text|processing-instruction|node$/
def PrimaryExpr path, parsed
case path
when VARIABLE_REFERENCE
varname = $1
path = $'
parsed << :variable
parsed << varname
#arry << @variables[ varname ]
when /^(\w[-\w]*)(?:\()/
#puts "PrimaryExpr :: Function >>> #$1 -- '#$''"
fname = $1
tmp = $'
#puts "#{fname} =~ #{NT.inspect}"
return path if fname =~ NT
path = tmp
parsed << :function
parsed << fname
path = FunctionCall(path, parsed)
when NUMBER
#puts "LITERAL or NUMBER: #$1"
varname = $1.nil? ? $2 : $1
path = $'
parsed << :literal
parsed << (varname.include?('.') ? varname.to_f : varname.to_i)
when LITERAL
#puts "LITERAL or NUMBER: #$1"
varname = $1.nil? ? $2 : $1
path = $'
parsed << :literal
parsed << varname
when /^\(/ #/
path, contents = get_group(path)
contents = contents[1..-2]
n = []
OrExpr( contents, n )
parsed.concat(n)
end
path
end
#| FUNCTION_NAME '(' ( expr ( ',' expr )* )? ')'
def FunctionCall rest, parsed
path, arguments = parse_args(rest)
argset = []
for argument in arguments
args = []
OrExpr( argument, args )
argset << args
end
parsed << argset
path
end
# get_group( '[foo]bar' ) -> ['bar', '[foo]']
def get_group string
ind = 0
depth = 0
st = string[0,1]
en = (st == "(" ? ")" : "]")
begin
case string[ind,1]
when st
depth += 1
when en
depth -= 1
end
ind += 1
end while depth > 0 and ind < string.length
return nil unless depth==0
[string[ind..-1], string[0..ind-1]]
end
def parse_args( string )
arguments = []
ind = 0
inquot = false
inapos = false
depth = 1
begin
case string[ind]
when ?"
inquot = !inquot unless inapos
when ?'
inapos = !inapos unless inquot
else
unless inquot or inapos
case string[ind]
when ?(
depth += 1
if depth == 1
string = string[1..-1]
ind -= 1
end
when ?)
depth -= 1
if depth == 0
s = string[0,ind].strip
arguments << s unless s == ""
string = string[ind+1..-1]
end
when ?,
if depth == 1
s = string[0,ind].strip
arguments << s unless s == ""
string = string[ind+1..-1]
ind = -1
end
end
end
end
ind += 1
end while depth > 0 and ind < string.length
return nil unless depth==0
[string,arguments]
end
end
end
end
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