Re: [Boost-users] [lambda] helping lambda to deduce return type and then avoid 'ret<T>'

Subject: Re: [Boost-users] [lambda] helping lambda to deduce return type and then avoid 'ret<T>'
From: Matthias Schabel (boost_at_[hidden])
Date: 2010-05-24 16:51:03

> and indeed for even very simple arithmetic user-defined classes (for
> example boost.units quantities) the lambda expression is poluted with
> many many ret<T> statements,
> for example
> 
> _1*_1/(_1+x)/(_1-x)
> 
> becomes
> 
> ret<anothertype>(ret<usertype>(_1*_1)/
> ret<othertype>(ret<usertype>(_1+x)/ret<usertype>(_1-x)));
> 
> the question is, is there a way to help lambda library to help
> deducing the return type to avoid the repeated use of ret<T>.

You should take a look at <boost/units/lambda.hpp> - Torsten Maehne contributed it to deal with interplay between lambda and units... Something similar might be worthwhile with interval as well.

Matthias