[1 [2 3]] : 4

# (map (@ 1 0-0)
#   (.sequence
#     (string (@ 1 1-2) ‘1’)
#   )
#   (.result
#     (string (@ 1 12-13) ‘4’)
#   )
# )
# (map (@ 1 0-0)
#   (.sequence
#     (string (@ 1 4-5) ‘2’)
#   )
#   (.result
#     (string (@ 1 12-13) ‘4’)
#   )
# )
# (map (@ 1 0-0)
#   (.sequence
#     (string (@ 1 6-7) ‘3’)
#   )
#   (.result
#     (string (@ 1 12-13) ‘4’)
#   )
# )
# :1:3–4: warning: alternation inside alternation is unnessary
#  [1 [2 3]] : 4
#     ^