Macro obfstr::random

macro_rules! random {
    ($ty:ident $(, $seeds:expr)* $(,)?) => { ... };
}

Compiletime random number generator.

Supported types are u8, u16, u32, u64, usize, i8, i16, i32, i64, isize, bool, f32 and f64.

The integer types generate a random value in their respective range.
The float types generate a random value in range of [1.0, 2.0).

While the result is generated at compiletime only the integer types are available in const contexts.

const RND: i32 = obfstr::random!(u8) as i32;
assert!(RND >= 0 && RND <= 255);

The behavior of the macro inside other macros can be surprising:

// When used as top-level input to macros, random works as expected
assert_ne!(obfstr::random!(u64), obfstr::random!(u64));

// When used inside the definition of a macro, random does not work as expected
macro_rules! inside {
	() => {
		assert_eq!(obfstr::random!(u64), obfstr::random!(u64));
	};
}
inside!();

// When provided a unique seed, random works as expected
// Note that the seeds must evaluate to a literal!
macro_rules! seeded {
	() => {
		assert_ne!(obfstr::random!(u64, "lhs"), obfstr::random!(u64, "rhs"));
	};
}
seeded!();

// Repeated usage in macros, random does not work as expected
macro_rules! repeated {
	($($name:ident),*) => {
		$(let $name = obfstr::random!(u64, "seed");)*
	};
}
repeated!(a, b);
assert_eq!(a, b);

// Provide additional unique seeds, random works as expected
macro_rules! repeated_seeded {
	($($name:ident),*) => {
		$(let $name = obfstr::random!(u64, "seed", stringify!($name));)*
	};
}
repeated_seeded!(c, d);
assert_ne!(c, d);