Marshall Clow <[EMAIL PROTECTED]> writes:
> I recently had a need for a functor to return a component of a
> std::pair, and I was
> surprised to see that they didn't exist either in the standard library
> or in boost.
>
> So, here they are. Are they useful to anyone else? Is there some reason that
> they don't already exist? Did I miss them somewhere?
>
> template <class T1, class T2>
> struct first: std::unary_function< std::pair <T1, T2>, T1>
> {
> T1 operator()(const std::pair <T1, T2> & x) const { return x.first;}
> };
>
> template <class T1, class T2>
> struct first: std::unary_function< std::pair <T1, T2>, T2>
> {
> T2 operator()(const std::pair <T1, T2> & x) const { return x.second;}
> };
>
The second one appears to be misnamed.
--
Dave Abrahams
Boost Consulting
www.boost-consulting.com
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