Re: Help improve regular expression for 24 hours format

[Jean Louis <bugs@gnu.support>]

* tomas@tuxteam.de <tomas@tuxteam.de> [2022-11-24 12:40]:
> > Thanks, I make it now this way:
> > 
> > (defvar rcd-rx-time (rx line-start (or "00" "01" "02" "03" "04" "05" "06" "07" "08" "09" "10" "11" 
> >  				       "12" "13" "14" "15" "16" "17" "18" "19" "20" "21" "22" "23")
> >  			":" (any "0" "1" "2" "3" "4" "5") (any digit)
> > 			line-end)
> >   "Regular expression for 24 hours format")
> 
> Hm. By distributive law, (or (seq (any "01") (any digit)) (seq "2" (any "03")))
> should cover your hours part. And for the minutes's first digit, remember that
> `any' can do ranges: (any "0-5") resp. (any (?0 . ?5))
> 
> >  ➜ "^\\(?:0[0-9]\\|1[0-9]\\|2[0-3]\\):[0-5][[:digit:]]$"
> 
> Even taking inspiration on what the "compiler" did of your expression might
> lead you to a simpler (and more readable!) expression, e.g.
> 
>   (or (seq "0" (any digit)) (seq "1" (any digit)) (seq "2" (any "0-3")))
> 
> although slightly longer than my first proposal (perhaps the second is
> "quicker", but I'd let the regexp compiler sort that out: you are
> optimising for the human reader, after all).


Do you have completed example using: 
(or (seq "0" (any digit)) (seq "1" (any digit)) (seq "2" (any "0-3"))) ?

-- 
Jean

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