core_recursion.obs

#~
# Core Recursion Test
# Tests recursive function calls and tail recursion
~#

class CoreRecursionTest {
    function : Main(args : String[]) ~ Nil {
        "Testing core recursion..."->PrintLine();

        pass := true;

        # Test simple recursion (factorial)
        result := Factorial(5);
        if(result <> 120) {
            pass := false;
            "  FAIL: Factorial(5)"->PrintLine();
        };

        # Test recursion with base case
        result := Factorial(0);
        if(result <> 1) {
            pass := false;
            "  FAIL: Factorial(0)"->PrintLine();
        };

        # Test Fibonacci
        result := Fibonacci(10);
        if(result <> 55) {
            pass := false;
            "  FAIL: Fibonacci(10)"->PrintLine();
        };

        # Test recursion with accumulator
        result := SumRange(1, 10);
        if(result <> 55) {
            pass := false;
            "  FAIL: SumRange(1, 10)"->PrintLine();
        };

        # Test mutual recursion
        even_result := IsEven(6);
        if(even_result = false) {
            pass := false;
            "  FAIL: IsEven(6)"->PrintLine();
        };

        odd_result := IsOdd(7);
        if(odd_result = false) {
            pass := false;
            "  FAIL: IsOdd(7)"->PrintLine();
        };

        if(pass) {
            "PASS: Core recursion"->PrintLine();
        } else {
            "FAIL: Core recursion"->PrintLine();
        };
    }

    function : Factorial(n : Int) ~ Int {
        if(n <= 1) {
            return 1;
        };
        return n * Factorial(n - 1);
    }

    function : Fibonacci(n : Int) ~ Int {
        if(n <= 1) {
            return n;
        };
        return Fibonacci(n - 1) + Fibonacci(n - 2);
    }

    function : SumRange(start : Int, end : Int) ~ Int {
        if(start > end) {
            return 0;
        };
        return start + SumRange(start + 1, end);
    }

    function : IsEven(n : Int) ~ Bool {
        if(n = 0) {
            return true;
        };
        return IsOdd(n - 1);
    }

    function : IsOdd(n : Int) ~ Bool {
        if(n = 0) {
            return false;
        };
        return IsEven(n - 1);
    }
}