def all_once

bendtorch@1.3.0.0 · tensor.bend:482

import Base

482# every axis 0..n-1 exactly once, from axis i
483def all_once(left: Nat, +p: List<&2, Nat>, +i: Nat) -> Bool:
484  match left:
485    case 0n:
486      True{}
487    case 1n+r:
488      # bend-lint: disable-next bend-lint-rules/performance/eager_branch -- a shape predicate over a list of rank <= 4, once per operation; the types and LAWS.bend read its Bool form not-expected-because: a match would change the definition the proofs reduce, for no measurable gain
489      Bool.and(Nat.is_eq(count(i, p), 1n), all_once(r, p, 1n+i))