[boost] Re: [regex] Escaping a search string?

From: Daniel Frey (daniel.frey_at_[hidden])
Date: 2003-08-08 01:49:59

Edward Diener wrote:
> That is a good point. However you always know what flags are passed to the
> regex function since they are available. That's not arguing against such a
> function as being part of the library itself but it is still doable by you.
> Furthermore you can set the flag mode you like to simplify your escaping,
> but of course this is not a general solution as the rest of the regular
> expression may require particular flags set.

That's the point and that's why I am asking for a library-based 
function. Sure I can write one myself, but this will always be a limited 
version of what the library could provide. I think the conversion 
function should accept the same flags like regex itself. Here's a signature:

template< typename stringT >
stringT convert_to_regex_literals( const stringT& s,
                                    flag_type f = regbase::normal );

I don't know whether we also need to provide traits somewhere, but I 
think John is the expert to answer that. (Yes, the name of the function 
is ugly - please find a better one :)

IMHO the library is the best place to implement such a function and keep 
it up-to-date and consistent. If we are lucky, it's also easier than 
doing it as a separate function as a function which is part of the 
library might be able to use some internals to create an easier 
implementation.

> That is not true. One just needs to read and understand the documentation on
> the particular flags and what they mean. There are no "secret innards" which
> retain information about escaping characters which you can't find for
> yourself by testing the flags.

Whatever I can do as a user, I think we've seen that I am not the only 
one who needs such a function and it doesn't make sense to reinvent it 
over and over again. Even if it's just for convenience, I think it's a 
desirable extension for the regex-library.

Regards, Daniel

-- 
Daniel Frey
aixigo AG - financial training, research and technology
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eMail: daniel.frey_at_[hidden], web: http://www.aixigo.de