def fold.edges

bend-visgraph@2.0.0.0 · visgraph.bend:855

import Base

855# `f(acc, src, dst, w)` over every edge of `g`, in the order the rope
856# holds them, from `acc`.
857def fold.edges(~A: Type, ~f: A -> U32 -> U32 -> F32 -> A, es: Edges, acc: A) -> A:
858  match es:
859    case ENil{}:
860      acc
861    case ECon{s, t, w, next}:
862      fold.edges(~A, ~f, next, f(acc, s, t, w))
863    case EJoin{a, b}:
864      fold.edges(~A, ~f, b, fold.edges(~A, ~f, a, acc))