Macro std::runtime::const_bake

macro const_bake($arg) { ... }

source

Bakes dynamic memory allocations into static items during constant evaluation.

Example

use std::collections::HashMap;
use std::runtime::const_bake;

const HASH: HashMap<u32, u32> = {
    let m: HashMap<u32, u32> = HashMap::new();
    m.insert(1, 2);
    m.insert(3, 4);
    m.const_bake!()
};

// The hashmap is constructed at compile time, and stored in rodata, so this is a simple lookup at runtime.
// Trying to modify the hashmap at runtime is undefined behavior.
assert_eq!(HASH.get(&1).unwrap(), 2);
assert_eq!(HASH.get(&3).unwrap(), 4);
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