Regex.cat: def of bend-kit-regex@0.8.0.0
Import: import bend-kit-regex@0.8.0.0/regex.bend as Regex
Lines 403-412 of bend-kit-regex@0.8.0.0/regex.bend: https://jend.leeeet.dev/read.txt?path=bend-kit-regex@0.8.0.0/regex.bend&start_line=403&end_line=412

import Base

def cat(a: Node, b: Node) -> Node:
  match a:
    case NEmpty{}:
      b
    case _:
      match b:
        case NEmpty{}:
          a
        case _:
          NCat{a, b}

Uses (1):
  https://jend.leeeet.dev/definition.txt?path=bend-kit-regex@0.8.0.0/regex.bend&name=Node