0. #lang racket
1.  
2. (define tests  (list " : text 1234"
3.                      " . text 1234"
4.                      " , text 1234"
5.                      " _ text 1234"
6.                      "   text 1234"
7.                      ))
8.  
9. (define patterns (list #px"[:alpha:]"
10.                        #px"[A-Za-z]"
11.                        #px"[:alnum:]"
12.                        #px"\\w"
13.                        #px"[A-Za-z0-9]"
14.                        #px"[:digit:]"
15.                        #px"\\d"
16.                        #px"[:xdigit:]"
17.                        #px"[A-Fa-f0-9]"
18.                        ))
19.  
20. (for [(p (in-list patterns))]
21.   (println p)
22.   (for [(t (in-list tests))]
23.     (printf "~v -> ~v~n" t (regexp-match p t ))
24.     ))

=>

#px"[:alpha:]" " : text 1234" -> '(":") " . text 1234" -> #f " , text 1234" -> #f " _ text 1234" -> #f "   text 1234" -> #f #px"[A-Za-z]" " : text 1234" -> '("t") " . text 1234" -> '("t") " , text 1234" -> '("t") " _ text 1234" -> '("t") "   text 1234" -> '("t") #px"[:alnum:]" " : text 1234" -> '(":") " . text 1234" -> #f " , text 1234" -> #f " _ text 1234" -> #f "   text 1234" -> #f #px"\\w" " : text 1234" -> '("t") " . text 1234" -> '("t") " , text 1234" -> '("t") " _ text 1234" -> '("_") "   text 1234" -> '("t") #px"[A-Za-z0-9]" " : text 1234" -> '("t") " . text 1234" -> '("t") " , text 1234" -> '("t") " _ text 1234" -> '("t") "   text 1234" -> '("t") #px"[:digit:]" " : text 1234" -> '(":") " . text 1234" -> '("t") " , text 1234" -> '("t") " _ text 1234" -> '("t") "   text 1234" -> '("t") #px"\\d" " : text 1234" -> '("1") " . text 1234" -> '("1") " , text 1234" -> '("1") " _ text 1234" -> '("1") "   text 1234" -> '("1") #px"[:xdigit:]" " : text 1234" -> '(":") " . text 1234" -> '("t") " , text 1234" -> '("t") " _ text 1234" -> '("t") "   text 1234" -> '("t") #px"[A-Fa-f0-9]" " : text 1234" -> '("e") " . text 1234" -> '("e") " , text 1234" -> '("e") " _ text 1234" -> '("e") "   text 1234" -> '("e")