Core.nullable: def of bend-schema-lib@0.4.1.0
Import: import bend-schema-lib@0.4.1.0/core.bend as Core
Lines 1718-1739 of bend-schema-lib@0.4.1.0/core.bend: https://jend.leeeet.dev/read.txt?path=bend-schema-lib@0.4.1.0/core.bend&start_line=1718&end_line=1739

import Base

def nullable(s: Schema) -> Bool:
  match s:
    case SOpt{i}:
      True{}
    case SOptional{i}:
      True{}  # absent and the inner's own null read as the same None
    case SRule{s2, tag}:
      nullable(s2)
    case SStrict{s2}:
      nullable(s2)
    case SStrLen{lo, hi, s2}:
      nullable(s2)
    case SListLen{lo, hi, s2}:
      nullable(s2)
    case STagged{k, n, cs, rest}:
      nullable(rest)
    case SVariant{n, vs, rest}:
      nullable(rest)
    case SEither{l, r}:
      Bool.or(nullable(l), nullable(r))  # a null would read as the inner's
    case _:
      False{}

Uses (3):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.or
  https://jend.leeeet.dev/definition.txt?path=bend-schema-lib@0.4.1.0/core.bend&name=Schema