/**
* Gets whether or not {@code tree} is an epsilon non-terminal in the parse tree. An epsilon tree
* is a node which does not contain any {@link TerminalNode} descendants.
*
* @param tree A node in a parse tree.
* @return {@code true} if {@code tree} is an epsilon node in the parse tree, otherwise {@code
* false}.
*/
public static boolean isEpsilon(@NonNull ParseTree tree) {
if (tree instanceof TerminalNode) {
return false;
}
Interval sourceInterval = tree.getSourceInterval();
return sourceInterval.b < sourceInterval.a;
}
/**
* Gets whether or not {@code a} starts after the start of {@code b}.
*
* @param a The first tree.
* @param b The second tree.
* @return {@code true} if {@code a} starts after the start of {@code b}, otherwise {@code false}.
*/
public static boolean startsAfterStartOf(@NonNull ParseTree a, @NonNull ParseTree b) {
// TerminalNode<? extends Token> startNodeA = getStartNode(a);
// TerminalNode<? extends Token> startNodeB = getStartNode(b);
// if (startNodeA == null || startNodeB == null) {
// throw new NotImplementedException();
// }
Interval sourceIntervalA = a.getSourceInterval();
Interval sourceIntervalB = b.getSourceInterval();
// if (sourceIntervalA.a == sourceIntervalB.a) {
// if (isAncestorOf(a, b)) {
// return true;
// }
//
// if (isEpsilon(a) || isEpsilon(b)) {
// // b could be a child of a later sibling of some ancestor of a
// throw new NotImplementedException();
// }
// }
return sourceIntervalA.a > sourceIntervalB.a;
}
/**
* Gets whether or not {@code a} ends before the end of {@code b}.
*
* @param a The first tree.
* @param b The second tree.
* @return {@code true} if {@code a} ends before the end of {@code b}, otherwise {@code false}.
*/
public static boolean endsBeforeEndOf(@NonNull ParseTree a, @NonNull ParseTree b) {
Interval sourceIntervalA = a.getSourceInterval();
Interval sourceIntervalB = b.getSourceInterval();
return sourceIntervalA.b < sourceIntervalB.b;
}
/**
* Gets whether or not {@code a} starts before the start of {@code b}.
*
* @param a The first tree.
* @param b The second tree.
* @return {@code true} if {@code a} starts before the start of {@code b}, otherwise {@code
* false}.
*/
public static boolean startsBeforeStartOf(@NonNull ParseTree a, @NonNull ParseTree b) {
Interval sourceIntervalA = a.getSourceInterval();
Interval sourceIntervalB = b.getSourceInterval();
return sourceIntervalA.a < sourceIntervalB.a;
}