From: Cédric Venet (cedric.venet_at_[hidden])
Date: 2007-07-10 10:06:19
Quoting Andrew Sutton <asutton_at_[hidden]>:
>> I'm not clear what your "truly optional" parameters are actually
>> for, but if (for example) they supply a functor could the default
>> value be some sort of identity functor?
>
> I guess it might be worthwhile to distinguish formally between
> optional parameters and those with default values. A parameter with
> default values is still a required input to a function even if the
> user doesn't explicitly pass a corresponding value. It's value is
> supplied by the specification. An optional parameter is one affects
> the function's behavior by its absence or presence in the argument list.
>
did you read:
http://www.boost.org/libs/parameter/doc/html/index.html#optional-parameters
http://www.boost.org/libs/parameter/doc/html/index.html#signature-matching-and-overloading
it does what I was trying to explain in my previous mail automaticaly
and should correspond to your need (optionnal parameter and compile
time function dispatching).