public Frame unify(RBTerm other, Frame f) {
// System.err.println("** entering unify " + this + " to: " + other);
if (other instanceof RBIgnoredVariable) return f;
RBTerm val = f.get(this);
if (val == null) {
other = other.substitute(f);
if (equals(other)) return f;
else if (other.freefor(this)) {
return bind(other, f);
} else return null;
} else return val.unify(other, f);
}
public Frame unify(RBTerm other, Frame f) {
if (!(other instanceof RBCompoundTerm)) {
if ((other instanceof RBVariable)) {
return other.unify(this, f);
}
return null;
}
RBCompoundTerm cother = (RBCompoundTerm) other;
if (!cother.getConstructorType().equals(getConstructorType())) {
return null;
}
return getArg().unify(cother.getArg(), f);
}
protected boolean sameForm(RBTerm other, Frame lr, Frame rl) {
if (!(other.getClass() == this.getClass())) return false;
else {
RBVariable binding = (RBVariable) lr.get(this);
if (binding == null) {
lr.put(this, other);
} else if (!binding.equals(other)) {
return false;
}
binding = (RBVariable) rl.get(other);
if (binding == null) {
rl.put(other, this);
return true;
} else {
return this.equals(binding);
}
}
}
