Looks like JavaScript, feels like Ruby, and it is a script language fitting in C programmers.
This project is maintained by Kray-G
Lambda is a simple style of an anonymous function.
& is used instead of function, and => expression is used instead of block.
var calc = &(func, a, b) => func(a, b);
System.println(calc(&(a, b) => a + b, 2, 3)); // 5
Note that => { /* block */ } is also available, so you can not use &(args) => { /* object */ }.
If you want to use an object, you have to write it with &(args) => ({ /* object */ }).
If the function has no arguments, a lambda can be written like &{...} style.
var a = 10;
var doit = &(block) => block();
System.println(doit(&{
return a + 100;
}));
This is not same as a block object above. A lambda can be wrapped with { and }, and it is the base of some simple syntax.
For example, the above doit function can be written as below.
var doit = { &(block) => block() };
As combining with the block style and a numbered parameter, you can remove an argument list itself.
For example, you can write the doit function as below.
var doit = { => _1() };
When the block style without an arrow of => operator, it can be just like a block statement with argument list inside block.
var add = { &(a, b)
return a + b;
};
System.println(add(1, 2)); // => 3
If you want to omit an argument list in the normal statement, you have to use it as a block object.
var add = &{
return _1 + _2;
};
System.println(add(1, 2)); // => 3
If the last argument in function call is a function object, that can be placed outside the argument list with a block style. For example, the 4 styles below are absolutely same.
callFunction(&(a, b) => a + b);
callFunction(&(a, b) => {
return a + b;
});
callFunction() { &(a, b) => a + b };
callFunction() { &(a, b)
return a + b;
};
In this case, you can omit an argument list itself without a block object style.
It means you do not have to use & before a block when it is the argument written outside the argument list.
function callFunction(f) {
System.println(f(1, 2)); // => 3
}
callFunction() {
return _1 + _2;
};
And you can also omit the parenthesis of function call when there is no argument list except the outside argument.
function callFunction(f) {
System.println(f(1, 2)); // => 3
}
callFunction {
return _1 + _2;
};
var fib = &(n) => {
if (n < 3) return n;
return fib(n-2) + fib(n-1);
};
System.println(fib(34)); // => 9227465
9227465
var 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));
}
System.println("fact(500) = ", fact(500));
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
fact(500) = 1220136825991110068701238785423046926253574342803192842192413588385845373153881997605496447502203281863013616477148203584163378722078177200480785205159329285477907571939330603772960859086270429174547882424912726344305670173270769461062802310452644218878789465754777149863494367781037644274033827365397471386477878495438489595537537990423241061271326984327745715546309977202781014561081188373709531016356324432987029563896628911658974769572087926928871281780070265174507768410719624390394322536422605234945850129918571501248706961568141625359056693423813008856249246891564126775654481886506593847951775360894005745238940335798476363944905313062323749066445048824665075946735862074637925184200459369692981022263971952597190945217823331756934581508552332820762820023402626907898342451712006207714640979456116127629145951237229913340169552363850942885592018727433795173014586357570828355780158735432768888680120399882384702151467605445407663535984174430480128938313896881639487469658817504506926365338175055478128640000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
var n = 10000;
var loop_while = &(n) => {
var v = 0, i = 0;
while (i <= n) {
v += i++;
}
return v;
};
System.println("while(%{n}) = ", loop_while(n));
while(10000) = 50005000
var n = 10000;
var loop_for = &(n) => {
var v = 0;
for (var i = 0; i <= n; ++i) {
v += i;
}
return v;
};
System.println("for(%{n}) = ", loop_for(n));
for(10000) = 50005000
var n = 10000;
var 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));
do_while(10000) = 50005000
var b = 1.7;
var test = &(a:dbl) => {
return a + b;
};
System.println(test(1.5));
3.2
var n = 10000;
var 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));
while(10000) = 46
var n = 10000;
var 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));
for(10000) = 46
var n = 10000;
var 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));
do_while(10000) = 46
var b = 100;
var c = 100;
function test() {
var d = 0;
return function (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);
}
b = 100
Divide by zero
Stack Trace Information:
at <main-block>(test.kx:27)
b = 102
c = 999
function calc(x, y, func) {
return func(x, y);
}
// The callback function can be put outside an arugument list.
System.println("add = " + calc(10, 2) { &(a, b) => a + b });
System.println("sub = " + calc(10, 2) { &(a, b) => a - b });
System.println("mul = " + calc(10, 2) { &(a, b) => a * b });
System.println("div = " + calc(10, 2) { &(a, b) => a / b });
System.println("add = " + calc(10, 2) { &() => _1 + _2 });
System.println("sub = " + calc(10, 2) { &() => _1 - _2 });
System.println("mul = " + calc(10, 2) { &() => _1 * _2 });
System.println("div = " + calc(10, 2) { &() => _1 / _2 });
System.println("add = " + calc(10, 2) { => _1 + _2 });
System.println("sub = " + calc(10, 2) { => _1 - _2 });
System.println("mul = " + calc(10, 2) { => _1 * _2 });
System.println("div = " + calc(10, 2) { => _1 / _2 });
add = 12
sub = 8
mul = 20
div = 5
add = 12
sub = 8
mul = 20
div = 5
add = 12
sub = 8
mul = 20
div = 5
var r = [1, 2, 3].map() {
return _1 * 2;
};
System.println(r); // => [2, 4, 6]
[2, 4, 6]
var r = [1, 2, 3].map {
return _1 * 2;
};
System.println(r); // => [2, 4, 6]
[2, 4, 6]
r = (1..10).sort { => _2 <=> _1 };
System.println(r); // => [10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]