Support for parsing basic XPath expressions.

This commit is contained in:
Yorick Peterse 2014-06-12 00:20:46 +02:00
parent 70f3b7fa92
commit eba2d9954d
5 changed files with 128 additions and 17 deletions

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@ -3,30 +3,74 @@
# #
class Oga::XPath::Parser class Oga::XPath::Parser
token T_AXIS T_COLON T_COMMA T_FLOAT T_INT T_IDENT T_OP T_STAR token T_AXIS T_COLON T_COMMA T_FLOAT T_INT T_IDENT T_STAR
token T_LBRACK T_RBRACK T_LPAREN T_RPAREN T_SLASH T_STRING token T_LBRACK T_RBRACK T_LPAREN T_RPAREN T_SLASH T_STRING
token T_PIPE T_AND T_OR T_ADD T_DIV T_MOD T_EQ T_NEQ T_LT T_GT T_LTE T_GTE
options no_result_var options no_result_var
prechigh
left T_EQ
right T_OR
preclow
rule rule
expressions xpath
: expressions_ { s(:xpath, *val[0]) } : expressions { s(:xpath, *val[0]) }
| /* none */ { s(:xpath) } | /* none */ { s(:xpath) }
; ;
expressions_ expressions
: expressions_ expression { val[0] << val[1] } : expressions expression { val[0] << val[1] }
| expression { val } | expression { val }
; ;
expression expression
: node_test : path
| node_test
| operator
| axis
| string
| number
;
path
: T_SLASH node_test { s(:path, val[1]) }
; ;
node_test node_test
: T_IDENT { s(:node, nil, val[0]) } : node_name { s(:node_test, val[0]) }
| T_IDENT T_COLON T_IDENT { s(:node, val[0], val[2]) } | node_name predicate { s(:node_test, val[0], *val[1]) }
; ;
node_name
# foo
: T_IDENT { s(:name, nil, val[0]) }
# foo:bar
| T_IDENT T_COLON T_IDENT { s(:name, val[0], val[1]) }
;
predicate
: T_LBRACK expressions T_RBRACK { val[1] }
;
operator
: expression T_EQ expression { s(:eq, val[0], val[2]) }
| expression T_OR expression { s(:or, val[0], val[2]) }
;
axis
: T_AXIS T_IDENT { s(:axis, val[0], val[1]) }
;
string
: T_STRING { s(:string, val[0]) }
;
number
: T_INT { s(:int, val[0]) }
| T_FLOAT { s(:float, val[0]) }
end end
---- inner ---- inner

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@ -0,0 +1,24 @@
require 'spec_helper'
describe Oga::XPath::Parser do
context 'axes' do
example 'parse an absolute path' do
parse_xpath('/foo').should == s(
:xpath,
s(:path, s(:node_test, s(:name, nil, 'foo')))
)
end
example 'parse a relative path' do
parse_xpath('foo').should == s(:xpath, s(:node_test, s(:name, nil, 'foo')))
end
example 'parse an expression using two paths' do
parse_xpath('/foo/bar').should == s(
:xpath,
s(:path, s(:node_test, s(:name, nil, 'foo'))),
s(:path, s(:node_test, s(:name, nil, 'bar')))
)
end
end
end

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@ -0,0 +1,37 @@
require 'spec_helper'
describe Oga::XPath::Parser do
context 'predicates' do
example 'parse a single predicate' do
parse_xpath('/foo[@class="bar"]').should == s(
:xpath,
s(
:path,
s(
:node_test,
s(:name, nil, 'foo'),
s(:eq, s(:axis, 'attribute', 'class'), s(:string, 'bar'))
)
)
)
end
example 'parse a predicate using the or operator' do
parse_xpath('/foo[@class="bar" or @class="baz"]').should == s(
:xpath,
s(
:path,
s(
:node_test,
s(:name, nil, 'foo'),
s(
:or,
s(:eq, s(:axis, 'attribute', 'class'), s(:string, 'bar')),
s(:eq, s(:axis, 'attribute', 'class'), s(:string, 'baz'))
)
)
)
)
end
end
end

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@ -1,5 +0,0 @@
require 'spec_helper'
describe Oga::XPath::Parser do
pending 'Write me!'
end

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@ -5,10 +5,11 @@ module Oga
# #
# @param [Symbol] type # @param [Symbol] type
# @param [Array] cihldren # @param [Array] cihldren
# @return [Oga::AST::Node] # @return [AST::Node]
# #
def s(type, *children) def s(type, *children)
return Oga::AST::Node.new(type, children) # TODO: add support for CSS AST nodes.
return Oga::XPath::Node.new(type, children)
end end
## ##
@ -32,6 +33,16 @@ module Oga
return Oga::XPath::Lexer.new(input).lex return Oga::XPath::Lexer.new(input).lex
end end
##
# Parses an XPath expression.
#
# @param [String] input
# @return [Oga::XPath::Node]
#
def parse_xpath(input)
return Oga::XPath::Parser.new(input).parse
end
## ##
# Parses the given XML and returns an AST. # Parses the given XML and returns an AST.
# #