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

=>

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