On Tue, Jun 17, 2008 at 9:31 PM, albert meyburgh <ameyburgh@gmail.com> wrote:
I believe this is a bug in the boost lambda constructor
I have worked around the problem with this wrapper:
template< typename T > struct LambdaConstructorWrapper : public boost::lambda::constructor< T > { typedef T result_type; };
and using it as such:
LambdaConstructorWrapper<MyType> myTypeConstructionWrapper;
std::transform( mycontainer.begin(), mycontainer.end(), std::back_inserter( redcontainer ), boost::bind(myTypeConstructionWrapper, _1, WHATEVER_PARM));
It seems to behave as expected by adding this one typedef so it's probably a bug? unless by design it's not supposed to be used this way for some reason that I don't see?
This is not a bug. As other have said, use boost::*lambda*::bind, not plain bind. Bind expect its first parameter to be a function pointer or a function object which exposes a result_type typedef for result type deduction. Boost.Lambda cannot have a result_type typedef because (in general) the result type depends on the argument type. Boost.Lambda uses the 'sig' protocol for that, which boost.bind doesn't support. boost::lambda::bind does. Of course in a perfect world both boost.bind and boost.lambda would be result_of compatible and these problems won't exist :) HTH, -- gpd