Tree.depth_to: def of bolt@1.27.0.0
Import: import bolt@1.27.0.0/src/syntax/tree.bend as Tree
Lines 197-208 of bolt@1.27.0.0/src/syntax/tree.bend: https://jend.leeeet.dev/read.txt?path=bolt@1.27.0.0/src/syntax/tree.bend&start_line=197&end_line=208

import Base
import bolt@1.27.0.0/src/lazy/lazy.bend as Lazy
import bolt@1.27.0.0/src/syntax/lex.bend as Lex

# how many groups sit open above the one that c closes (counting it); 0 when
# none does. A `>` closes only an angle group on top: inside `(..)`, `[..]`
# or `{..}` it is an operator, even within `<..>`
def depth_to(stack: List<&2, Frame>, +cc: String) -> Nat:
  match stack:
    case Nil{}:
      0n
    case Con{FGroup{Lex.Tok{k, +t, l, c2}, kids}, rest}:
      Lazy.stop(Nat, String.eq(closer(t), cc), 1n,
        _u => Lazy.stop(Nat, String.eq(cc, ">"), 0n, _v => depth_to.up(depth_to(rest, cc))))
    case Con{other, rest}:
      0n

Uses (9):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String.eq
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/lazy/lazy.bend&name=stop
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/syntax/lex.bend&name=Tok
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/syntax/tree.bend&name=Frame
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/syntax/tree.bend&name=closer
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/syntax/tree.bend&name=depth_to.up