AoC 2023, day 1 (dc part 1)

[ +d ] sF                   # first = ord (+0)
[ s. z3<L q ] sN            # junk char, loop if more input

0                           # sum
?
[
    0d                      # sum ... char2 char1 last first
    [
        3R 48-              # char1 -> ASCII ordinal - 48

        # d 1>N             # next if <1 (ASSUME: no ASCII chars < '1')
        d 9<N               # next if >9

        r d0=F              # last ord first
        3Rs.                # last = ord (by junking old)

        z3<L
    ] dsLx

    rA*++                   # sum += 10 * last + first (because string reversed)
    ? z1<M
] dsMx

[Part 1: ]np