Re: std::binder1st and transform_iterator (was Re: [boost] iterator adaptors & concept checks)

From: David Abrahams (abrahams_at_[hidden])
Date: 2001-03-29 23:50:42

Not a stupid idea, but I think this introduces overheads that we don't want
to pay for.

-Dave

----- Original Message -----
From: "Arun Sivaramakrishnan" <aruns_at_[hidden]>
To: boost_at_[hidden]

>   How about storing a pointer or a scoped_ptr to the
AdaptableUnaryFunction
>  intialized to NULL in the default constructor of
> transform_iterator_policies
> and intialized to a valid one in its other constructor,
> ie
>
> template <class AdaptableUnaryFunction>
> struct transform_iterator_policies : public default_iterator_policies
> {
>     transform_iterator_policies() { }
>     transform_iterator_policies(const AdaptableUnaryFunction& f)
>      : m_pf(new AdaptableUnaryFunction(f)) { }
>
>     template <class Reference, class Iterator>
>     Reference dereference(type<Reference>, const Iterator& iter) const
>         { return *m_pf(*iter); }
>
>     scoped_ptr<AdaptableUnaryFunction> m_pf;
> };
>
>