perl - How can I make $1 return alternatives without a substitution regex? -

I recently incorporated the project into the logic of code and database elements. Business logic, such as expat, regular expressions, and function names, are recorded in the database, while reading general code such as files, making xml from xpath etc. are in code base.

Most (if not all) the methods that use regular expressions are structured like this:

  if ($ entry = ~ / $ regex /) {$ req_value = $ 1; }  

This means that only $ 1 is available and you must always have your RegEx written in your $ 1 to give you the desired results.

Problem:

The result of the following string is either

  '2.6.9-78.1.6.ELsmp (SMP)' or '2.6. 9-78.1.6.ELsmp should be ' 

based on SMP's existence. $ 1 $ entry is not enough for [0].

  $ entry [0] = qq | Linux version 2.6.9-78.1.6.ELsmp (brewbuilder@hs20-bc2-2.build .redhat.com) (GCC version 3.4.6 20060404 (Red Hat 3.4.6-10)) # 1 SMP Wednesday 24 September 05 : 41: 12 ADT 2008. | $ Entry [1] = qq | Linux version 2.6.9-78.0.5.ELsmp (brewbuilder@hs20-bc2-2.build.redhat.com) (GCC version 3.4.6 20060404 (Red Hat 3.4.6-10)) # 1 Wed Sep 24 05: 41:12 EDT 2008. |  

So my solution:

  my $ mutable = ''; My $ regex = qr / ((\ d. *?) \ S + (?:. *)? (SMP) ((? {$ Mutable = "$ 2 ($ 3)"})) | (\ *?)) \ S + /; If ($ entry [$ i] = ~ / $ regex /) {$ req_value = $ 1; $ Req_value = $ mutable if ($ mutable ne ''); $ Mutable = ''; Unfortunately, the existence of a 'variable' in the database makes this solution unacceptable.  
 My questions are:  
 
  
 or   
 
 How do I replace using regex   
 Thanks.  
 
 
 -text "itemprop =" text "> 
 Are trapped until you can not talk to those people who control the code by you that you are using to normalize in any way. The good news is that you only need a little more, maybe  
  if (my @ fields = $ _ = ~ / $ pat /) {$ req_value = join "" => Defined Grep ($ _), @ fields; }  
 
 This works because a successful regular-expression matching in the list context gives all the caps substrings,  i.e. ,  $ 1  ,  $ 2 ,  $ 3 , and so on as appropriate. 
 
 with a single pattern, 
 
  qr / (\ d + (?: [-.] \ W +) *) (?:. * (SMP) )? /  
 
 The code above is  2.6.9-78.1.6.ELsmp SMP  and  2.6.9-78.0.5.ELsmp  in < Code> $ req_value . Capture filter for  grep define ($ _)  not taken subpotter. Without it, you get unsolicited price warnings for non-SMP case. 
 
 The downside is that every regular expression should be reviewed so that all capturing groups should actually go to  $ req_value . For example, the pattern of a person using 
 
  qr / (xyz) OS (version \ d + | v- \ d +) /  
 
 As is so now, only XYZ will have to go to  $ req_value , but the version number will be included using the above generalization if it is unwanted, then regular expression 
 
 Do not capture  qr / (xyz) OS (?: Version \ d + | v- \ d +) /  
 
 (i.e., for the above pattern  $ 2  does not produce Is): It's only for grouping.