6 releases
0.2.3 | Aug 22, 2024 |
---|---|
0.2.2 | May 21, 2022 |
0.2.1 | Feb 22, 2022 |
0.1.1 | Jan 9, 2022 |
#2160 in Procedural macros
67 downloads per month
Used in 2 crates
(via bool_vec)
10KB
107 lines
Count macro
A macro to allow for compile time counting
How to use this
Every instance of _int_
will be replaced with either a literal or an ident.
count_macro::count
will panic in debug mode if counter exceeds usize.
If you wish to wrap to 0, please use count_macro::wrapping_count
.
Examples
Ident to literal
use count_macro::count;
let a = count!(vec![_int_, _int_, _int_]);
assert_eq!(a, vec![0, 1, 2]);
Ident to ident
use count_macro::count;
count! {
let a_int_ = "Hello";
let a_int_ = "World";
}
assert_eq!(a0, "Hello");
assert_eq!(a1, "World");
In macro
use count_macro::count;
macro_rules! my_macro {
($($v:expr),*) => {
count!{
$(
let _ = $v; // Ignoring $v
println!("{}", _int_);
)*
}
};
}
my_macro!('@', '@', '@', '@'); // Will print from 0 to 3
Multiple counters
with _int_countername_
you'll be able to create a new counter called "countername".
This won't be incremented by _int_
or any other counter such as _int_0_
or _int_x_
.
use count_macro::count;
// With two different counters
// _int_ does not increment _int_name_
count! {
let a_int_ = _int_name_;
let a_int_ = _int_name_;
let a_int_ = _int_name_;
}
assert_eq!(a0, 0);
assert_eq!(a1, 1);
assert_eq!(a2, 2);
Dependencies
~2.1–3MB
~54K SLoC