正则表达式库错误

Question

I used T-Rex regular expression library to validate an entered string to the following regular expression

(“(([A-PR-UWYZ][A-HK-Y]{0,1}[0-9]{1,2}[ABCEHMNPRTVWXY]{0,1}|GIR)\s{0,2}([0-9][ABD-HJLN-UW-Z]{2}))”)

But a string like "A11AA" that should be passed fails. Could you help me ?

You can find T-Rex source code in http://sourceforge.net/projects/tiny-rex/ .

Answer 1

A guess, right out of the blue:

#include "trex.h"
#include <stdio.h>
#include <string.h>

#ifdef _UNICODE
#define trex_sprintf swprintf
#else
#define trex_sprintf sprintf
#endif

int main(int argc, char* argv[])
{
    const TRexChar *begin,*end;
    TRexChar sTemp[200];
    const TRexChar *error = NULL;
    TRex *x = trex_compile(_TREXC(

  "("
    "("
      "("
        "[A-P]|[R-U]|[WYZ]"
      ")"
      "("
        "[A-H]|[K-Y]"
      ")?"

      "[0-9]{1,2}"

      "([ABCEHMNPRTVWXY]?|GIR)"
     ")"

     "\\s{0,2}"
     "("
       "[0-9]"
       "("
        "[AB]|[D-H]|[JL]|[N-U]|[W-Z]"
       "){2}"
     ")"
   ")"),&error);

    if(x) {
        trex_sprintf(sTemp,_TREXC("A11AA"));
        if(trex_search(x,sTemp,&begin,&end))
        {
            int i,n = trex_getsubexpcount(x);
            TRexMatch match;
            for(i = 0; i < n; i++)
            {
                TRexChar t[200];
                trex_getsubexp(x,i,&match);
                trex_sprintf(t,_TREXC("[%%d]%%.%ds\n"),match.len);
                trex_printf(t,i,match.begin);
            }
            trex_printf(_TREXC("match! %d sub matches\n"),trex_getsubexpcount(x));
        }
        else {
            trex_printf(_TREXC("no match!\n"));
        }
        trex_free(x);
    }
    else {
        trex_printf(_TREXC("compilation error [%s]!\n"),error?error:_TREXC("undefined"));
    }
    return 0;
}

Answer 2

As a rule, you have to check thrice before calling "Bug!" on the compiler, library or other tools (the developers presumably know what they are doing, and test their stuff). Besides, you could embarass yourself in public ;-)

AFAICS, your "A11AA" string just doesn't match the given expression, which expects some further stuff after that.

Try simpler expressions, matching parts of your string and working up. Check the exact meaning of the expressions (the languages of different tools are infuriatingly different).