[cmake-developers] slow regex implementation in RegularExpression

[Alexandru Ciobanu]

On 2011-11-23, at 12:24 PM, Brad King wrote:

> On 11/23/2011 12:20 PM, Alexandru Ciobanu wrote:
>> to compile ITK using CMake+TRE. And there was at least one regex that
>> TRE refused to compile. 
> 
> What was it, and where in the ITK code is it?

The regex in question is:
    ^[^][:/*?]+\$

And it appears at this location in the ITK source tree:
    CMake/ExternalData.cmake:347

And the expression is correct, because you're allowed to have the ] metacharacter inside a [^xyz] class if it comes immediately after ^.

TRE does not do it the same way, see (http://laurikari.net/tre/documentation/regex-syntax/ the "Bracket expressions" section):

> To include a literal ] in the list, make it either the first item, the second endpoint of a range, or enclose it in [. and.].

sincerely,
Alex
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