diff options
| -rw-r--r-- | raku/luhn/Luhn.rakumod | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/raku/luhn/Luhn.rakumod b/raku/luhn/Luhn.rakumod index 4b704b5..8efafc0 100644 --- a/raku/luhn/Luhn.rakumod +++ b/raku/luhn/Luhn.rakumod @@ -1,4 +1,11 @@ unit module Luhn; -sub is-luhn-valid(Str $input is copy --> Bool) is export { +sub is-luhn-valid($input is copy --> Bool) is export { + return False if $input.comb.grep(/\d|\s/).join ne $input; + $input = $input.comb.grep(/\d/)>>.Int; + return False if $input.elems < 2; + + ([+] gather for $input.reverse.kv -> $k, $v { + take $k !%% 2 ?? ($_ > 9 ?? $_ - 9 !! $_) !! $v with $v * 2; + }) %% 10; } |