Compose.co.alias: def of yaml-for-bend@0.1.1.0
Import: import yaml-for-bend@0.1.1.0/compose.bend as Compose
Lines 493-502 of yaml-for-bend@0.1.1.0/compose.bend: https://jend.leeeet.dev/read.txt?path=yaml-for-bend@0.1.1.0/compose.bend&start_line=493&end_line=502

import Base
import yaml-for-bend@0.1.1.0/token.bend as T
import yaml-for-bend@0.1.1.0/value.bend as V

# An alias: a copy of its node, counted at the node's full size. An alias
# inside the node it names would make a cycle, which a tree can't hold.
def co.alias(co: Co, +name: String, +limit: Nat, +at: T.Mark) -> Result<&2, &2, T.Error, Co>:
  match co:
    case Co{+stack, +anchors, count, root, docs, opened, depth, copied}:
      when(Result<&2, &2, T.Error, Co>, opens(stack, name),
        u => Fail{content("found an alias to a node that holds it: " ++ name ++ " is recursive, and a tree can't hold a cycle", at)},
        u => when(Result<&2, &2, T.Error, Co>, Bool.not(found(Map.has(&2, Anchored, anchors, name))),
          u => Fail{content("found an alias to an unknown anchor: " ++ name, at)},
          u => alias.got(Map.get(Anchored, Anchored{V.Null{}, 0n}, anchors, name), Co{stack, anchors, count, root, docs, opened, depth, copied}, limit, at)))

Uses (17):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.not
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Map.get
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Map.has
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Result
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String.append
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/compose.bend&name=Anchored
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/compose.bend&name=Co
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/compose.bend&name=alias.got
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/compose.bend&name=content
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/compose.bend&name=found
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/compose.bend&name=opens
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/compose.bend&name=when
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/token.bend&name=Error
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/token.bend&name=Mark
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/value.bend&name=Yaml