Subject: Re: [boost] Assign V2 - first impression
From: Simonson, Lucanus J (lucanus.j.simonson_at_[hidden])
Date: 2011-06-24 16:33:19
er wrote:
>> Now if you want to repeat the operation of inserting the element f(
>> x ), I'm not sure how you do that with Range, but with V2, after
>> learning the syntax, it's relatively straightforward:
>>
>> ( put_front<1>( cont ) % ( _data = f ) % ( _repeat = n ) )( 1, 10,
>> 100, 1000 );
>>
>
> This was suggested, which is probably the best:
>
> push_front<1>( cont , _data = f, _repeat = n )( 1, 10, 100, 1000 );
>
> More generally,
>
> // Fixed arity:
> push_front<I>( cont , options... )( a1,...,aI,...,z1,...,zI );
>
> // Variadic
> push_front( cont , options... )( args1 )...( argsn );
>
> where in each case (fixed and variadic), options... modify the
> semantics
> of the subsequent calls to operator().
Can we change the name of _data to something like _filter? Also, I don't like the pre and post _ names in the interface. If you want to use a convention related to pre and post _ in the implementation details that's fine, but I don't think it is appropriate in the interface. If you use boost.parameter I think you would get a post _ charater, I believe, so having both pre and post _ for different reasons seems confusing.
Also, it would be nice to have iterator pair and range be acceptable alternatives to the fixed arity and variadic options shown above. I realize that would require some SFINAE, but I think being able to consistently initialize containers and then mix the forms would be a big plus.
char* cstr[] = "Hello world!";
std::vector<char> chrs;
push_back( chrs , filter = to_upper )( cstr, cstr+5 )( '\0' );
chrs contains a null terminated string "HELLO".
There is then a whole area of treating std::string like a container by specializing some of your library interfaces that would really be handy.
Regards,
Luke