public ASTNode substituteCommonTerms(ASTNode tree, IExpressionContext context) {
ASTNode copy = tree.createCopy(true);
final Map<Integer, List<ASTNode>> result = new HashMap<>();
final INodeVisitor visitor =
new INodeVisitor() {
@Override
public boolean visit(ASTNode node, int currentDepth) {
final Integer hash = node.hashCode();
List<ASTNode> existing = result.get(hash);
if (existing == null) {
existing = new ArrayList<>();
result.put(hash, existing);
}
existing.add(node);
return true;
}
};
tree.visitInOrder(visitor);
outer:
for (Map.Entry<Integer, List<ASTNode>> entry : result.entrySet()) {
final int hash = entry.getKey();
if (entry.getValue().size() <= 1) {
continue;
}
for (ASTNode n : entry.getValue()) {
if (n instanceof IdentifierNode) {
continue outer;
}
}
// create new variable
final ASTNode value = entry.getValue().get(0).createCopy(true);
final Identifier identifier = context.createIdentifier(value);
final boolean substituted = replaceMatchingTermsWithVariable(context, copy, hash, identifier);
if (substituted) {
debugPrintln(
"SUBSTITUTE: "
+ value
+ " => "
+ identifier
+ " ( "
+ entry.getValue().size()
+ " times )");
} else {
context.remove(identifier);
}
}
return copy;
}
public ASTNode expand(ASTNode term, IExpressionContext context, boolean deleteExpandedVars) {
final ASTNode result = term.createCopy(true);
final Set<Identifier> expandedIdentifiers = new HashSet<>();
boolean expanded = false;
do {
expanded = false;
final MutatingNodeVisitor visitor =
new MutatingNodeVisitor(context) {
@Override
public void visit(ASTNode node, IExpressionContext context, IIterationContext it) {
final ASTNode unwrapped = unwrap(node);
if (node.hasParent() && unwrapped instanceof IdentifierNode) {
final ASTNode expanded = unwrapped.evaluate(context);
if (expanded != null && expanded != unwrapped) {
debugPrintln("EXPAND: Expanding " + node + " -> " + expanded);
expandedIdentifiers.add(((IdentifierNode) unwrapped).getIdentifier());
node.replaceWith(expanded);
it.astMutated();
}
}
}
};
expanded = applyPostOrder(result, visitor);
} while (expanded);
if (deleteExpandedVars) {
for (Identifier id : expandedIdentifiers) {
context.remove(id);
}
}
return result;
}
