XPath

@uml Represent a subset of XPath XML path syntax for use in identifying nodes in parse trees.

Split path into words and separators {@code /} and {@code //} via ANTLR itself then walk path elements from left to right. At each separator-word pair, find set of nodes. Next stage uses those as work list.

The basic interface is {@link XPath#findAll ParseTree.findAll}{@code (tree, pathString, parser)}. But that is just shorthand for:

<pre> {@link XPath} p = new {@link XPath#XPath XPath}(parser, pathString); return p.{@link #evaluate evaluate}(tree); </pre>

See {@code org.antlr.v4.test.TestXPath} for descriptions. In short, this allows operators:

<dl> <dt>/</dt> <dd>root</dd> <dt>//</dt> <dd>anywhere</dd> <dt>!</dt> <dd>invert; this must appear directly after root or anywhere operator</dd> </dl>

and path elements:

<dl> <dt>ID</dt> <dd>token name</dd> <dt>'string'</dt> <dd>any string literal token from the grammar</dd> <dt>expr</dt> <dd>rule name</dd> <dt>*</dt> <dd>wildcard matching any node</dd> </dl>

Whitespace is not allowed.

class XPath {

enum string WILDCARD;

XPathElement[] elements;

protected

Parser parser;

this(Parser parser, string path);

XPathElement[] split(string path);

XPathElement getXPathElement(Token wordToken, bool anywhere);

static ParseTree[] findAll(ParseTree tree, string xpath, Parser parser);

ParseTree[] evaluate(ParseTree t);

}

Constructors

this this(Parser parser, string path): Undocumented in source.

Members

Functions

evaluate ParseTree[] evaluate(ParseTree t): @uml Return a list of all nodes starting at {@code t} as root that satisfy the path. The root {@code /} is relative to the node passed to {@link #evaluate}.
getXPathElement XPathElement getXPathElement(Token wordToken, bool anywhere): @uml Convert word like {@code *} or {@code ID} or {@code expr} to a path element. {@code anywhere} is {@code true} if {@code //} precedes the word.
split XPathElement[] split(string path): @uml TODO: check for invalid token/rule names, bad syntax

Static functions

findAll ParseTree[] findAll(ParseTree tree, string xpath, Parser parser): Undocumented in source. Be warned that the author may not have intended to support it.

Variables

NOT enum string NOT;: @uml word for invert operator
WILDCARD enum string WILDCARD;: @uml word not operator/separator
elements XPathElement[] elements;: Undocumented in source.
parser Parser parser;: Undocumented in source.
path string path;: Undocumented in source.

XPath

Constructors

Members

Functions

Static functions

Variables

Meta

Source