Macro node_engine::impl_math_node

macro_rules! impl_math_node {
    ( $mod_name:ident, $ty_name:ident, $v:ident, $name:expr ) => { ... };
    ( $mod_name:ident, $ty_name:ident, $a:ident, $b:ident, $out:ident, $name:expr ) => { ... };
}