[Req] navigating with XPath

[ArsenShnurkov]

XPath uses path expressions to select nodes or node-sets.

brief introduction:
http://www.w3schools.com/xsl/xpath_syntax.asp

EBNF-like grammar:
http://www.w3.org/TR/xquery-xpath-parsing/#id-grammar

.net class library contains a set of classes and interfaces which automates that.
(starting from System.Xml.XPath, IXPathNavigable )

I propose to implement such access to the tree of Match-es, which are returned as result of parsing

[furesoft]

good idea

[ArsenShnurkov]

2003-03-02, XPath Querying Over Objects with ObjectXPathNavigator, Steve Saxon, https://msdn.microsoft.com/en-us/library/ms950764.aspx

"You could pass the IXPathNavigator over the object directly into an XSLT transform without needing to serialize it first."

https://github.com/AndrewMayorov/ObjectXPathNavigator

...

Another approach is Linq to Objects

[ArsenShnurkov]

http://goessner.net/articles/JsonPath/

XPath	JSONPath	Description
/	$	the root object/element
.	@	the current object/element
/	. or []	child operator
..	n/a	parent operator
//	..	recursive descent. JSONPath borrows this syntax from E4X.
*	*	wildcard. All objects/elements regardless their names.
@	n/a	attribute access. JSON structures don't have attributes.
[]	[]	subscript operator. XPath uses it to iterate over element collections and for predicates. In Javascript and JSON it is the native array operator.
|	[,]	Union operator in XPath results in a combination of node sets. JSONPath allows alternate names or array indices as a set.
n/a	[start:‌end:step]	array slice operator borrowed from ES4.
[]	?()	applies a filter (script) expression.
n/a	()	script expression, using the underlying script engine.
()	n/a	grouping in Xpath

http://programmers.stackexchange.com/questions/264706/xslt-equivalent-for-json

[ArsenShnurkov]

https://www.sitepen.com/blog/2010/11/02/resource-query-language-a-query-language-for-the-web-nosql/

RQL is designed to be URI friendly, leveraging URI encoding and designated delimiters for syntax that works perfectly in web requests.
RQL is designed to be extensible.