Re: [boost] std::string algorithms and regular expressions

From: Jeremy Siek (jsiek_at_[hidden])
Date: 2001-06-12 13:26:05

These would be great! This kind of functionality is especially important
for entry-level C++ programmers. With that in mind we should strive to
keep this library easy to use (as easy as Beman's examples below).

On Tue, 12 Jun 2001, Beman Dawes wrote:

> I'd like to see a Boost string algorithms library.
>
> For the sake of discussion, let's assume:
>
> * The interface is via free functions (rather than modifying
> std::basic_string or inheriting from it).
>
> * The examples below use std::string but a real library would deal with
> wstrings too, if not the full basic_string template.
>
> * The examples ignore obvious variations like rfind, and size_type p=0
> arguments, but a real library would supply variations.
>
> The set of Boost algorithms I'd like to discuss is:
>
>     size_type find( const string & s, const string & search );
>     string & erase( string & s, const string & search );
>     string & erase_all( string & s, const string & search );
>     string & replace( string & s, const string & search,
>                                   const string & replacement );
>     string & replace_all( string & s, const string & search,
>                                   const string & replacement );
>
> Presumable the overloads would include "const char *" for the "search"
> argument.
>
> Example usage:
>
>     string s ( "How now brown brown cow" );
>     string::size_type p;
>     p = find( s, "br" );          // p == 8
>     erase( s, "br" );             // s == "How now own brown cow"
>     replace_all( s, "ow", "*" );  // s == "H* n* *n br*n c*"
>
> Now the tricky part - users would also like options:
>
>     The "search" argument to be a regular expression.
>
>     The "search" comparison to be treated as case insensitive.
>
>  From a user perspective, it seems to me overloading the "search" argument
> is preferable to having if_regex, erase_regex, etc.  The same for case
> insensitive operations.
>
> I guess the user would then write things like:
>
>     string s ( "axacab" );
>     erase( s, regex("a(b|c)") );  // s == "axab"
>
> Will that work?  I don't see why not.
>
> Even if that works, I'm not sure how to apply the same approach to case
> insensitive compares, including issues of locale.
>
> The point of this posting is to get both general and specific feedback.  Is
> a string algorithms library a good idea?  Is anyone is interested in
> working on such a library?
>
> --Beman
>
>
>
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----------------------------------------------------------------------
 Jeremy Siek                        www: http://www.lsc.nd.edu/~jsiek/
 Ph.D. Candidate, IU B'ton          email: jsiek_at_[hidden]
 Summer Manager, AT&T Research      phone: [phone]
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