Smart Loops (‘loop’)#

Added in version 3.0.

How To Use#

Smart loops, declared using the loop keyword, are able to be optimized better by the compiler than normal loops. There are a few different ways to use smart loops.

Firstly, you can simply declare loop(), which results in an infinite loop, similar to while(true).

Otherwise, you can follow the pattern loop(typename varname : range, increment).
  • ‘typename’ specifies a type for the loop’s variable

    • You can omit it, letting it default to const int

  • ‘varname’ is an identifier declaring the name of the loop’s variable

    • You can omit it to not name the variable

    • If you do so, you must also omit ‘typename’ and the :

  • The : can be replaced with in

  • ‘range’ is a value range

    • The loop’s variable starts at the low end, and increments by the increment value until it would exit the range

  • ‘increment’ is the increment value of the range

    • You can omit it, letting it default to 1

    • If you do so, you must also omit the ,

    • If a negative increment is supplied, the loop’s variable will start at the high end of the range, and count down.

void infinite()
{
        loop() // similar to 'while(true)'
        {
                // Run something every frame here
                Waitframe();
        }
}
loop(x : 1=..10, 2) // similar to 'for(int x = 1; x < 10; x += 2)'
        printf("x is %d\n", x);
// Output:
// x is 1
// x is 3
// x is 5
// x is 7
// x is 9
loop(0=..3)
        printf("Test!\n");
// Output:
// Test!
// Test!
// Test!
loop(const long l : 0=..1, 100L)
        printf("l is %d\n", l);
// Output:
// l is 0
// l is 0.01
// l is 0.02
// l is 0.03
//     (this continues for a while)
// l is 0.98
// l is 0.99

Annotations#

Smart loops support the @AlwaysRunEndpoint annotation. This annotation takes a string literal parameter, which must be one of "int", "long", or "float"- though the long and float options behave identically.

If this annotation is supplied to a loop that is looping over a range, the end of the range will always be included in the iteration. In the "int" mode, the end-of-range value will be truncated- in "float" or "long" mode, it will not.

loop(x : 0=..6, 2)
        printf("%d\n", x);
// Output:
// 0
// 2
// 4
@AlwaysRunEndpoint("int")
loop(x : 0=..6, 2)
        printf("%d\n", x);
// Output:
// 0
// 2
// 4
// 5
@AlwaysRunEndpoint("float")
loop(x : 0=..6, 2)
        printf("%d\n", x);
// Output:
// 0
// 2
// 4
// 5.9999

Related: Loop Else, Break, Continue

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