[Development] Regular expression libraries for QRegExp
thiago at kde.org
Wed Nov 23 15:35:57 CET 2011
On Tuesday, 22 de November de 2011 15:07:46 Giuseppe D'Angelo wrote:
> On 32bit Linux:
> text data bss dec hex filename
> 387691 728 176 388595 5edf3 libpcre-
> 260245 580 12 260837 3fae5 libpcre/lib/libpcre.so
> 159869 416 12 160297 27229 libpcre-
> First line is with JIT and UCP, second UCP only, third neither of them.
Question: where does it get its Unicode tables from? Are they compiled in, or
does it link to another library, such as ICU?
Here, my libpcre links to nothing but libc.
> Ok. My only concern was that const methods of the pattern will have to
> compile it (... modify the shared instance) behind the scenes. I'm not
> sure if you wanted to get rid of these behaviours (thus, the "compiled
> pattern" class).
The API must not suffer from implementation details. We make a good API, then
we find a way to make it work.
At first thought, I'd say that the pattern class should be a regular,
implicitly-shared, atomic copy-on-write value class. If you call a non-const
method, it detaches.
There should be no const methods that modify internal caches. Period. If you
compile the pattern, it's a non-const method and it detaches. The pattern is
also not the matcher class, it does not keep the captures, so there's no data
to be modified in the *pattern* when you do a matching.
It may provide a convenience contains() or indexIn() function that execute
matching. Those must be const and not modify the pattern.
If you want to deal with captures, you need a different class from the pattern.
That's the matcher class.
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
Software Architect - Intel Open Source Technology Center
PGP/GPG: 0x6EF45358; fingerprint:
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