def hex4.go

bend-net-json@0.3.0.0 · json.bend:139

import Base

139def hex4.go(s: String, +acc: U32, n: Nat) -> Maybe<&2, Esc>:
140  match s:
141    case SNil{}:
142      match n:
143        case 0n:
144          Some{Esc{acc, SNil{}}}
145        case 1n+k:
146          None{}
147    case SCon{Chr{+c}, t}:
148      match n:
149        case 0n:
150          Some{Esc{acc, SCon{Chr{c}, t}}}
151        case 1n+k:
152          +h = hexd(c)
153          Bool.pick(Maybe<&2, Esc>, U32.is_eq(h, 99), None{}, hex4.go(t, (acc * 16 + h : U32), k))