// Checks if one of the operands is reducible
public boolean isOperandsReducible() {
for (Expression o : operands) {
if (o.reducible()) {
return true;
} else if (!IsValue.isValue(o)) {
return false;
}
}
return false;
}
public Vector<Expression> reduceOperandsByOneStep() {
Vector<Expression> new_operands = operands;
for (int i = 0; i < new_operands.size(); i++) {
if (new_operands.get(i).reducible()) {
new_operands.set(i, new_operands.get(i).oneStep());
} else if (!IsValue.isValue(new_operands.get(i))) {
return new_operands;
}
}
return new_operands;
}
// Q: When is Function Application reducible?
// A: When either its operands or operator is reducible
public boolean reducible() {
return operator.reducible()
|| (IsValue.isValue(operator) && isOperandsReducible())
|| (IsValue.isValue(operator) && allOperandsAreValues());
}
public boolean allOperandsAreValues() {
for (Expression o : operands) {
if (!IsValue.isValue(o)) return false;
}
return true;
}
