On Aug 31, 2011, at 5:11 PM, Emil Dotchevski wrote:
On Wed, Aug 31, 2011 at 1:13 PM, Gordon Woodhull <gordon@woodhull.com> wrote:
On Aug 31, 2011, at 3:01 PM, Emil Dotchevski wrote:
I do agree however that the call syntax should not rely on <>. One reason is that it turns off ADL. Another reason is that sometimes an implicit conversion to match an existing non-template overload is preferable to instantiating a template.
The function overload customization point in Conversion uses a dummy parameter and no <>. convert_to<> is a just a more pleasant wrapper over that. So I think these language features are still available.
What makes it more pleasant? Is it more convenient? In what use cases?
We are talking about a library that emulates overloading static_cast. The wrapper makes it look somewhat like static_cast<>(), whereas if you directly had to use the customization point it would be a mess: conversion::convert_to<Target>(source); versus explicit_convert_to(source, conversion::type_tag<Target>()) In other words, the ugliness is confined to the definition of conversions and doesn't spill over into their use. But the conversion definitions do get to benefit from ADL... actually I don't see how a conversion library could benefit from implicit conversions of the target type, but I might be missing something. Cheers, Gordon