Macro brain_flak_macro::brain_flak

macro_rules! brain_flak {
    ($left:expr, $right:expr $(,)? => $($code:tt)*) => { ... };
    ($input:expr $(,)? => $($code:tt)*) => { ... };
}

Stack manipulation with Brain-Flak.

Brain-Flak reference table

Nilad	Return value	Action
()	+1	None
[]	Height of active stack	None
{}	Value of top of active stack	Pops the top value off the active stack
<>	0	Switches the active stack

Monad	Return value	Action
(...)	Inside value	Pushes the inside value to the top of the active stack
[...]	Negative inside value	None
{...}	Sum of the inside values across all executions	Executes the inside while the top of the inside stack is not 0
<...>	0	None

The table above is shamelessly copied from https://github.com/DJMcMayhem/Brain-Flak/wiki/Reference. More information about Brain-Flak can be found on Esolang wiki page, as well as on its GitHub repository

Refer to the crate document for more information about the macro.