Comptime ​

Comptime is short for compile-time. Means all of compile-time actions.

Jule provides compile-time functionalites empowered by language design and the standard std::comptime library that provides a beefed-up experience for compile-time. This library provides functionalities that can be used for various purposes. It is designed for compile-time only, it does not add anything for runtime execution.

Comptime statements do not have runtime equivalents because they are designed specifically for compile-time. Therefore any comptime statement that should result in runtime execution will cause a compile error.

Basic Comptime Evaluation ​

Basic comptime expression are really basic feature of Jule's comptime. Means comptime evaluated expressions with primitive type literals and built-in functions.

List of supported primitive types: str, bool, f32, f64, i8, i16, i32, i64, u8, u16, u32, u64, int, uint, uintptr

For example:

List of Some Effects of Basic Comptime Evaluation ​

• Evaluates of supported primitive type literals
• Evaluates indexing expressions as constant data of supported literals such as strings
• Evaluates slicing expressions as constant data of supported literals such as strings
• Compiler checks boundaries for indexing expressions with supported literals such as strings or slices
• Compiler checks boundaries for indexing expressions with supported fixed-size types such as arrays
• The built-in len function returns constant length data for constant strings
• The built-in cap function returns constant length data for constant strings

Constant Variables ​

Constant variables are immutable, compile-time evaluated expression storage variables and one of the elementary features of the compile-time functionality of Jule.

You can store and use any compile-time expression with constant variables. Your compiler allows you to use these expressions as if they were variables until the compilation process finishes.

For example:

use comptime for std::comptime

const MagicNumber = 20

fn main() {
    let x = MagicNumber
    const xt = comptime::TypeOf(x)
    outln(xt.Kind())
}