[cmake-developers] slow regex implementation in RegularExpression

[Alexandru Ciobanu]

On 2011-11-17, at 3:26 PM, Alexander Neundorf wrote:

>> [ Regular expressions syntax ]
>> In terms of regular expressions syntax, the only difference that I've seen
>> is that TRE treats the curly brackets "{" and "}" as special characters,
>> because it uses them for its "approximate matching".  Details here:
>> http://laurikari.net/tre/documentation/regex-syntax/
>> 
>> The only CMake component that uses curly brackets in a regexp is:
>>    Modules/FindJNI.cmake
>> but it was trivial to fix because they were used as mere delimiters.
> 
> Well, but there are cmake files out there (i.e. all existing cmake-based 
> projects) which also must behave basically exactly the same as before, 
> otherwise their builds might break.
> 
> Not sure how to achieve this.
> A policy ?
> 

Actually it is very easy to make it transparent and thus not need to modify any .cmake files.

We just need to escape the curly brackets:
   {   ->   \{
   }   ->   \}
in the regular expression before compiling it.

This way we'll have full compatibility with previous regexp syntax.

sincerely,
Alex CIobanu