Loop
Generated from the engine's own definition: compute-engine's symbol, which we neither extend nor document by hand. No examples yet — the crosswalk is the reason it has a page.
Imperative loop, evaluated **for effect**. `Loop(body)` repeatedly evaluates `body` until it yields a `Break` or `Return`. `Loop(body, Element(x, coll), …)` iterates `body` in nested iteration over the Element clauses (later clauses see earlier bindings; independent clauses produce a Cartesian product). The loop value is `Nothing`, or the value carried by a `Break`/`Return`. For a value-producing comprehension use `Comprehension` or `Map`.
Loop(body: expression, iterators: expression*) -> anyas compute-engine declares it