/** supports chains only */
public boolean hasOpposite(Formula formula) {
LispTree tree = formula.toLispTree();
if (tree.isLeaf()) {
String fbProperty =
FreebaseInfo.isReverseProperty(tree.value) ? tree.value.substring(1) : tree.value;
return freebaseInfo.fbPropertyHasOpposite(fbProperty);
} else {
// Un-reverse everything.
String binary1 = tree.child(2).child(0).value;
binary1 = FreebaseInfo.isReverseProperty(binary1) ? binary1.substring(1) : binary1;
String binary2 = tree.child(2).child(1).child(0).value;
binary2 = FreebaseInfo.isReverseProperty(binary2) ? binary2.substring(1) : binary2;
return freebaseInfo.fbPropertyHasOpposite(binary1)
&& freebaseInfo.fbPropertyHasOpposite(binary2);
}
}
public Formula equivalentFormula(Formula formula) {
LispTree tree = formula.toLispTree();
return equivalentFormula(tree);
}
/** supports chains only */
public boolean isReversed(Formula formula) {
LispTree tree = formula.toLispTree();
if (tree.isLeaf()) return FreebaseInfo.isReverseProperty(tree.value);
else return FreebaseInfo.isReverseProperty(tree.child(2).child(0).value);
}