Package io.github.douira.glsl_transformer.traversal

Class DynamicParseTreeWalker

java.lang.Object

org.antlr.v4.runtime.tree.ParseTreeWalker

io.github.douira.glsl_transformer.traversal.DynamicParseTreeWalker

public class DynamicParseTreeWalker
extends ParseTreeWalker

The dynamic parse tree walker can handle some structural modification of a node's child array. This enables injection of new nodes without disallowing such modifications to happen during tree walking.

Field Summary

Fields

Modifier and Type	Field	Description
static final DynamicParseTreeWalker	DEFAULT	The default instance of the dynamic parse tree walker.

Constructor Summary

Constructors

Constructor	Description
DynamicParseTreeWalker()

Method Summary

Modifier and Type	Method	Description
void	walk(ParseTreeListener listener, ParseTree tree)	Copied from ANTLR's ParseTreeWalker.walk(org.antlr.v4.runtime.tree.ParseTreeListener, org.antlr.v4.runtime.tree.ParseTree) but with compensation for items being added to the child array.

Methods inherited from class org.antlr.v4.runtime.tree.ParseTreeWalker

enterRule, exitRule

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

DEFAULT

public static final DynamicParseTreeWalker DEFAULT

The default instance of the dynamic parse tree walker.

Constructor Details

DynamicParseTreeWalker

public DynamicParseTreeWalker()

Method Details

walk

public void walk(ParseTreeListener listener,
 ParseTree tree)

Copied from ANTLR's ParseTreeWalker.walk(org.antlr.v4.runtime.tree.ParseTreeListener, org.antlr.v4.runtime.tree.ParseTree) but with compensation for items being added to the child array. TODO: Check if using empty terminal nodes in general messes up ANTLR's parse tree matching (with patterns or xpath)

Overrides:

walk in class ParseTreeWalker

Implementation Note:

Node removal never reduces the length of the array so "removal" is not an issue. (since removed nodes are instead replaced with empty terminal nodes) Node addition after the current position is ok since the length is dynamically determined in the loop. The only problematic thing is node addition before the current position for which the current iteration index needs to be compensated for. This is done by fast-forwarding the iteration index after the walk happened until the current node is found again.