Macro mice::for_

macro_rules! for_ {
    ($elem:pat in $iter:expr => $blk:block) => { ... };
}

A for loop-alike for StreamingIterator.

use ::mice::parse::parse_expression;
let (_tokens, program) = parse_expression::<AstInterp>("4d6k3 + 2".as_bytes()).unwrap().1;
for_! { (term, _ancestors) in program.postorder() => {
    // do stuff with `term` and maybe `_ancestors`
}}