Series.scan: def of bend-visgraph@2.0.0.0
Import: import bend-visgraph@2.0.0.0/src/series.bend as Series
Lines 28-41 of bend-visgraph@2.0.0.0/src/series.bend: https://jend.leeeet.dev/read.txt?path=bend-visgraph@2.0.0.0/src/series.bend&start_line=28&end_line=41

import Base

# Base's String.lines recurses once per character, too deep for the JS
# lane's stack, so this walks the text with tail calls. `h` is the character
# before `s`, `nl` whether it is a newline, and `cur` the line before `h`,
# last character first.
def scan(s: String, nl: Bool, +h: Char, cur: String, +line: U32, st: Parsed) -> Parsed:
  match s nl:
    case SNil{} True{}:
      step(String.reverse(cur), line, st)
    case SNil{} False{}:
      step(String.reverse(SCon{h, cur}), line, st)
    case SCon{+h2, t} True{}:
      scan(t, Char.is_eq(h2, '\n'), h2, SNil{}, (line + 1 : U32), step(String.reverse(cur), line, st))
    case SCon{+h2, t} False{}:
      scan(t, Char.is_eq(h2, '\n'), h2, SCon{h, cur}, line, st)

Uses (9):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Char
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Char.is_eq
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String.reverse
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.add
  https://jend.leeeet.dev/definition.txt?path=bend-visgraph@2.0.0.0/src/series.bend&name=Parsed
  https://jend.leeeet.dev/definition.txt?path=bend-visgraph@2.0.0.0/src/series.bend&name=step