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Native

Overview

Keyword native is a style of function definition used when you want to compile it to the native machine code. You can just write a native instead of function keyword for that.

native fib(n) {
    if (n < 3) return n;
    return fib(n-2) + fib(n-1);
}

Supports and Limitations

It is very fast but there are some limitations.

  • All variables are defined as a type. Available type is int, big, dbl, str, bin, obj, int[], dbl[], or native.
    • If type information is omitted, the type would be followings.
      • On argument, it become automatically int.
      • Without initializer on declaration, it become automatically int.
      • With initializer on declaration, it is decided by the result of right hand side.
        • When it can not be decided, a compile error will occur.
    • For int
      • Integer value is NOT automatically promoted to a big integer, it will just overflow instead.
      • Math functions like Math.pow(2, 10) or 2.pow(10) are supported.
    • For big
      • It is supported as a big integer, but there is a little note. Please be careful when you use it.
        • This type will use all values as a big integer value even if it is a small integer like 1. Therefore the performance may be quit slower than doing it with a VM execution in some cases.
        • The native code will generate so many Big Integer objects in calculating with a big integer. In a current design, those objects are not collected by GC during a native execution. All objects of a big integer will be collected after returning to the VM execution. This means so many memory may be used and a performance may be quit slow.
        • For example, you should NOT use a big integer in a native function like a recursive fibonacci calculation.
    • For dbl
      • Math functions like Math.pow(2.0, 10.0) or 2.0.pow(10.0) are supported.
    • For str
      • str is only supported for adding 2 strings and multiplying string by integer.
    • For bin
      • It is supported as an array of byte.
    • For int[] and dbl[]
      • It is currently just supported as an array of integer or double.
    • For native.
      • native function's return type is shown like native funcname(arg):int.
      • Even in this case, you can omit :int as the type of a return value and automatically make it int.
  • For function call.
    • Can not call a script function. Only can call a native function.
  • For statement and expression.
    • Exceptions with try-catch-finally is supported, but a stack trace is not available.
    • Switch-Case is supported, but the case label should be an integer value or expression.
    • The lexical scope and variables are available, but the type must be clarified.
      • If you omit the type, it will assume the integer.
      • If the type is mismatched, runtime exception will occur.
  • Supported platform.
    • Supporting 64bit only.
    • Libraries are supporting x64, ARM, MIPS, but it is not tested except x64 Windows or Linux.

Basic Expressions

See below for examples of basic expressions in native.

Math Functions

Especially, see below for examples of Math functions.

Supported Switch-Case/When

Switch-Case/When is now supported in native function. But the case label should be an integer type. See below for examples of Switch-Case/When in native.

Supported Array

In native function it can use an array of integer and double. See below for examples of how to use an array in native.

Examples

Example 1. Fibonacci

Code

native fib(n) {
    if (n < 3) return n;
    return fib(n-2) + fib(n-1);
}
System.println(fib(34));  // => 9227465

Result

9227465

Example 2. Factorial

Code

native fact(a) {
    if (a < 1) return 1;
    return a * fact(a-1);
}
for (var i = 0; i <= 20; ++i) {
    System.println("fact(%{i}) = ", fact(i));
}

Result

fact(0) = 1
fact(1) = 1
fact(2) = 2
fact(3) = 6
fact(4) = 24
fact(5) = 120
fact(6) = 720
fact(7) = 5040
fact(8) = 40320
fact(9) = 362880
fact(10) = 3628800
fact(11) = 39916800
fact(12) = 479001600
fact(13) = 6227020800
fact(14) = 87178291200
fact(15) = 1307674368000
fact(16) = 20922789888000
fact(17) = 355687428096000
fact(18) = 6402373705728000
fact(19) = 121645100408832000
fact(20) = 2432902008176640000

Example 3. While Loop

Code

var n = 10000;
native loop_while(n) {
    var v = 0, i = 0;
    while (i <= n) {
        v += i++;
    }
    return v;
}
System.println("while(%{n}) = ", loop_while(n));

Result

while(10000) = 50005000

Example 4. For Loop

Code

var n = 10000;
native loop_for(n) {
    var v = 0;
    for (var i = 0; i <= n; ++i) {
        v += i;
    }
    return v;
}
System.println("for(%{n}) = ", loop_for(n));

Result

for(10000) = 50005000

Example 5. Do-While Loop

Code

var n = 10000;
native loop_do_while(n) {
    var v = 0, i = 0;
    do {
        v += i++;
    } while (i <= n);
    return v;
}
System.println("do_while(%{n}) = ", loop_do_while(n));

Result

do_while(10000) = 50005000

Example 6. Evaluation with double

Code

var b = 1.7;
native test(a:dbl):dbl {
    return a + b;
}
System.println(test(1.5));

Result

3.2

Example 7. Label to While

Code

var n = 10000;
native loop_while(n) {
    var v = 0, i = 0;
    LABEL::
    while (1) {
        while (i <= n) {
            if (i == 9) {
                ++i;
                continue;
            }
            v += i++;
            if (i > 10) break LABEL;
        }
    }
    return v;
}
System.println("while(%{n}) = ", loop_while(n));

Result

while(10000) = 46

Example 8. Label to For

Code

var n = 10000;
native loop_for(n) {
    var v = 0;
    LABEL::
    while (1) {
        for (var i = 0; i <= n; ++i) {
            if (i == 9) continue;
            v += i;
            if (i == 10) break LABEL;
        }
    }
    return v;
}
System.println("for(%{n}) = ", loop_for(n));

Result

for(10000) = 46

Example 9. Label to Do-While

Code

var n = 10000;
native loop_do_while(n) {
    var v = 0, i = 0;
    LABEL::
    while (1) {
        do {
            if (i == 9) {
                ++i;
                continue;
            }
            v += i++;
            if (i > 10) break LABEL;
        } while (i <= n);
    }
    return v;
}
System.println("do_while(%{n}) = ", loop_do_while(n));

Result

do_while(10000) = 46

Example 10. Too deep to call a native

Code

native tooDeep(n) {
    return tooDeep(n-1);    # infinite loop!
}
tooDeep(100);

Result

Uncaught exception: No one catch the exception.
NativeFunctionException: Too deep to call function
Stack Trace Information:
        at <main-block>(test.kx:4)

Example 11. Try-Catch-Finally

Code

var b = 100;
var c = 100;
function test() {
    var d = 0;
    return native (n) {
        var a = 100;
        try {
            try {
                a /= d;
            } finally {
                ++b;
            }
            b %= 9;
        } catch (e) {
            c = 999;
            throw;
        } finally {
            ++b;
        }
        return a;
    };
}

var try_catch = test();
try {
    System.println("b = ", b);
    System.println(try_catch(10));
} catch (e) {
    System.println(e.what());
    e.printStackTrace();
} finally {
    System.println("b = ", b);
    System.println("c = ", c);
}

Result

b = 100
Divide by zero
Stack Trace Information:
        at <main-block>(test.kx:27)
b = 102
c = 999

Example 12. Finally with return

Code

var a, b, c, d;

function check(name, test) {
    a = b = c = d = 0;
    System.println("%{name}:");
    System.println("    a = %{a}, b = %{b}, c = %{c}, d = %{d}");

    try {
        test();
        System.println("    a = %{a}, b = %{b}, c = %{c}, d = %{d}");
    } catch (e) {
        System.println("Exception: ", e.what());
    }
}

native test1_native() {
    try {
        try {
            return 1;
        } finally {
            a = 100;
        }
    } finally {
        b = 1000;
    }
}

native test_native(f:native) {
    try {
        try {
            return f();
        } finally {
            c = 10000;
        }
    } finally {
        d = 100000;
    }
}

function test1_function() {
    try {
        try {
            return 1;
        } finally {
            a = 100;
        }
    } finally {
        b = 1000;
    }
}

function test_function(f) {
    try {
        try {
            return f();
        } finally {
            c = 10000;
        }
    } finally {
        d = 100000;
    }
}

check("native -> native", &() => test_native(test1_native));
check("function -> native", &() => test_function(test1_native));
check("function -> function", &() => test_function(test1_function));

Result

native -> native:
    a = 0, b = 0, c = 0, d = 0
    a = 100, b = 1000, c = 10000, d = 100000
function -> native:
    a = 0, b = 0, c = 0, d = 0
    a = 100, b = 1000, c = 10000, d = 100000
function -> function:
    a = 0, b = 0, c = 0, d = 0
    a = 100, b = 1000, c = 10000, d = 100000

Example 13. Finally with throw.

Code

var a, b, c, d;

function check(name, test) {
    a = b = c = d = 0;
    System.println("%{name}:");
    System.println("    a = %{a}, b = %{b}, c = %{c}, d = %{d}");

    try {
        test();
    } catch (e) {
        ;
    }
    System.println("    a = %{a}, b = %{b}, c = %{c}, d = %{d}");
}

native test1_native() {
    try {
        try {
            throw 1;
        } finally {
            a = 100;
        }
    } finally {
        b = 1000;
    }
}

native test_native(f:native) {
    try {
        try {
            return f();
        } finally {
            c = 10000;
        }
    } finally {
        d = 100000;
    }
}

function test1_function() {
    try {
        try {
            throw 1;
        } finally {
            a = 100;
        }
    } finally {
        b = 1000;
    }
}

function test_function(f) {
    try {
        try {
            return f();
        } finally {
            c = 10000;
        }
    } finally {
        d = 100000;
    }
}

check("native -> native", &() => test_native(test1_native));
check("function -> native", &() => test_function(test1_native));
check("function -> function", &() => test_function(test1_function));

Result

native -> native:
    a = 0, b = 0, c = 0, d = 0
    a = 100, b = 1000, c = 10000, d = 100000
function -> native:
    a = 0, b = 0, c = 0, d = 0
    a = 100, b = 1000, c = 10000, d = 100000
function -> function:
    a = 0, b = 0, c = 0, d = 0
    a = 100, b = 1000, c = 10000, d = 100000

Example 14. Quicksort with Integer

Code

native quicksort(a:int[], first, last) {
    var i = first;
    var j = last;
    var x = a[(first + last) / 2];
    while (true) {
        while (a[i] < x) i++;
        while (x < a[j]) j--;
        if (i >= j) break;

        [a[i], a[j]] = [a[j], a[i]];
        ++i; --j;
    }
    if (first  < i - 1)
        quicksort(a, first , i - 1);
    if (j + 1 < last)
        quicksort(a, j + 1, last);
}

function show(title, a) {
    System.print(title);
    a.each(&(e) => System.print(" %2d" % e));
    System.print("\n");
}

function demo() {
    var a = [69, 63, 88, 85, 26, 77, 51, 42, 16, 4, 20, 18, 18, 40, 23, 26, 24, 63, 96, 59];

    show("Before:", a);
    quicksort(a, 0, a.length() - 1);
    show("After: ", a);
}

demo();

Result

Before: 69 63 88 85 26 77 51 42 16  4 20 18 18 40 23 26 24 63 96 59
After:   4 16 18 18 20 23 24 26 26 40 42 51 59 63 63 69 77 85 88 96

Example 15. Quicksort with Double

Code

native quicksort(a:dbl[], first, last) {
    var i = first;
    var j = last;
    var x = a[(first + last) / 2];
    while (true) {
        while (a[i] < x) i++;
        while (x < a[j]) j--;
        if (i >= j) break;

        [a[i], a[j]] = [a[j], a[i]];
        ++i; --j;
    }
    if (first  < i - 1)
        quicksort(a, first , i - 1);
    if (j + 1 < last)
        quicksort(a, j + 1, last);
}

function show(title, a) {
    System.print(title);
    a.each(&(e) => System.print(" %3.1f" % e));
    System.print("\n");
}

function demo() {
    var a = [69, 63, 88, 85, 26, 77, 51, 42, 16, 4, 20, 18, 18, 40, 23, 26, 24, 63, 96, 59].map { => Double.parseDouble(_1 / 10) };

    show("Before:", a);
    quicksort(a, 0, a.length() - 1);
    show("After: ", a);
}

demo();

Result

Before: 6.9 6.3 8.8 8.5 2.6 7.7 5.1 4.2 1.6 0.4 2.0 1.8 1.8 4.0 2.3 2.6 2.4 6.3 9.6 5.9
After:  0.4 1.6 1.8 1.8 2.0 2.3 2.4 2.6 2.6 4.0 4.2 5.1 5.9 6.3 6.3 6.9 7.7 8.5 8.8 9.6

Example 16. Big Integer

Code

function fact(n) {
    if (n <= 1) {
        return 1;
    }
    return n * fact(n - 1);
}

native factb(n:big):big {
    if (n <= 1) {
        return 1;
    }
    return n * factb(n - 1);
}

var f1 = fact(1000);
var f2 = factb(1000);
System.println(("fact(1000)  = %d") % f1);
System.println(("factb(1000) = %d") % f2);
System.println("The result is ", f1 == f2 ? "same." : "different.");

Result

fact(1000)  = 402387260077093773543702433923003985719374864210714632543799910429938512398629020592044208486969404800479988610197196058631666872994808558901323829669944590997424504087073759918823627727188732519779505950995276120874975462497043601418278094646496291056393887437886487337119181045825783647849977012476632889835955735432513185323958463075557409114262417474349347553428646576611667797396668820291207379143853719588249808126867838374559731746136085379534524221586593201928090878297308431392844403281231558611036976801357304216168747609675871348312025478589320767169132448426236131412508780208000261683151027341827977704784635868170164365024153691398281264810213092761244896359928705114964975419909342221566832572080821333186116811553615836546984046708975602900950537616475847728421889679646244945160765353408198901385442487984959953319101723355556602139450399736280750137837615307127761926849034352625200015888535147331611702103968175921510907788019393178114194545257223865541461062892187960223838971476088506276862967146674697562911234082439208160153780889893964518263243671616762179168909779911903754031274622289988005195444414282012187361745992642956581746628302955570299024324153181617210465832036786906117260158783520751516284225540265170483304226143974286933061690897968482590125458327168226458066526769958652682272807075781391858178889652208164348344825993266043367660176999612831860788386150279465955131156552036093988180612138558600301435694527224206344631797460594682573103790084024432438465657245014402821885252470935190620929023136493273497565513958720559654228749774011413346962715422845862377387538230483865688976461927383814900140767310446640259899490222221765904339901886018566526485061799702356193897017860040811889729918311021171229845901641921068884387121855646124960798722908519296819372388642614839657382291123125024186649353143970137428531926649875337218940694281434118520158014123344828015051399694290153483077644569099073152433278288269864602789864321139083506217095002597389863554277196742822248757586765752344220207573630569498825087968928162753848863396909959826280956121450994871701244516461260379029309120889086942028510640182154399457156805941872748998094254742173582401063677404595741785160829230135358081840096996372524230560855903700624271243416909004153690105933983835777939410970027753472000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
factb(1000) = 402387260077093773543702433923003985719374864210714632543799910429938512398629020592044208486969404800479988610197196058631666872994808558901323829669944590997424504087073759918823627727188732519779505950995276120874975462497043601418278094646496291056393887437886487337119181045825783647849977012476632889835955735432513185323958463075557409114262417474349347553428646576611667797396668820291207379143853719588249808126867838374559731746136085379534524221586593201928090878297308431392844403281231558611036976801357304216168747609675871348312025478589320767169132448426236131412508780208000261683151027341827977704784635868170164365024153691398281264810213092761244896359928705114964975419909342221566832572080821333186116811553615836546984046708975602900950537616475847728421889679646244945160765353408198901385442487984959953319101723355556602139450399736280750137837615307127761926849034352625200015888535147331611702103968175921510907788019393178114194545257223865541461062892187960223838971476088506276862967146674697562911234082439208160153780889893964518263243671616762179168909779911903754031274622289988005195444414282012187361745992642956581746628302955570299024324153181617210465832036786906117260158783520751516284225540265170483304226143974286933061690897968482590125458327168226458066526769958652682272807075781391858178889652208164348344825993266043367660176999612831860788386150279465955131156552036093988180612138558600301435694527224206344631797460594682573103790084024432438465657245014402821885252470935190620929023136493273497565513958720559654228749774011413346962715422845862377387538230483865688976461927383814900140767310446640259899490222221765904339901886018566526485061799702356193897017860040811889729918311021171229845901641921068884387121855646124960798722908519296819372388642614839657382291123125024186649353143970137428531926649875337218940694281434118520158014123344828015051399694290153483077644569099073152433278288269864602789864321139083506217095002597389863554277196742822248757586765752344220207573630569498825087968928162753848863396909959826280956121450994871701244516461260379029309120889086942028510640182154399457156805941872748998094254742173582401063677404595741785160829230135358081840096996372524230560855903700624271243416909004153690105933983835777939410970027753472000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
The result is same.