persistence.antlr.ASTPair Maven / Gradle / Ivy
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package persistence.antlr;
/* ANTLR Translator Generator
* Project led by Terence Parr at http://www.jGuru.com
* Software rights: http://www.antlr.org/license.html
*
*/
import persistence.antlr.collections.AST;
/** ASTPair: utility class used for manipulating a pair of ASTs
* representing the current AST root and current AST sibling.
* This exists to compensate for the lack of pointers or 'var'
* arguments in Java.
*/
public class ASTPair {
public AST root; // current root of tree
public AST child; // current child to which siblings are added
/** Make sure that child is the last sibling */
public final void advanceChildToEnd() {
if (child != null) {
while (child.getNextSibling() != null) {
child = child.getNextSibling();
}
}
}
/** Copy an ASTPair. Don't call it clone() because we want type-safety */
public ASTPair copy() {
ASTPair tmp = new ASTPair();
tmp.root = root;
tmp.child = child;
return tmp;
}
public String toString() {
String r = root == null ? "null" : root.getText();
String c = child == null ? "null" : child.getText();
return "[" + r + "," + c + "]";
}
}