transcendental-lisp/src/main/java/function/builtin/math/MathFunction.java

44 lines
1.6 KiB
Java

package function.builtin.math;
import recursion.TailCall;
import sexpression.Cons;
import sexpression.LispNumber;
import sexpression.SExpression;
import java.util.function.BiFunction;
import java.util.function.Function;
import static recursion.TailCalls.done;
import static recursion.TailCalls.tailCall;
class MathFunction {
Function<LispNumber, LispNumber> singleValueOperation;
BiFunction<LispNumber, LispNumber, LispNumber> multipleValueOperation;
public MathFunction(Function<LispNumber, LispNumber> singleValueOperation,
BiFunction<LispNumber, LispNumber, LispNumber> multipleValueOperation) {
this.singleValueOperation = singleValueOperation;
this.multipleValueOperation = multipleValueOperation;
}
public TailCall<LispNumber> callTailRecursive(Cons argumentList) {
Cons remainingArguments = (Cons) argumentList.getRest();
SExpression firstArgument = argumentList.getFirst();
LispNumber number1 = (LispNumber) firstArgument;
if (remainingArguments.isNull())
return done(singleValueOperation.apply(number1));
SExpression secondArgument = remainingArguments.getFirst();
LispNumber number2 = (LispNumber) secondArgument;
LispNumber operationResult = multipleValueOperation.apply(number1, number2);
SExpression remainingNumbers = remainingArguments.getRest();
if (remainingNumbers.isNull())
return done(operationResult);
return tailCall(() -> callTailRecursive(new Cons(operationResult, remainingNumbers)));
}
}