Macro amethyst_rendy::rendy::hal::spec_const_list

macro_rules! spec_const_list {
    ( @ $ ( , ) ? ) => { ... };
    (
@ $ head_id : expr => $ head_constant : expr $ (
, $ tail_id : expr => $ tail_constant : expr ) * $ ( , ) ? ) => { ... };
    (
$ ( $ id : expr => $ constant : expr ) , * $ ( , ) ? ) => { ... };
    ( $ ( $ constant : expr ) , * $ ( , ) ? ) => { ... };
}

Macro for specifying list of specialization constatns for EntryPoint.