String.nil_append_sym: law of bend-mathlib@0.8.1.0
Import: import bend-mathlib@0.8.1.0/string.bend as String
Lines 540-543 of bend-mathlib@0.8.1.0/string.bend: https://jend.leeeet.dev/read.txt?path=bend-mathlib@0.8.1.0/string.bend&start_line=540&end_line=543

import Base

# The empty string is a left identity for append: "" ++ a = a, reversed to rewrite toward the simple side.
law nil_append_sym:
  for -a: String
  {a == String.append(SNil{}, a) : String}

Uses (4):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.sym
  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=bend-mathlib@0.8.1.0/string.bend&name=nil_append