Re: A config.hpp #define for operator member templates

From: Daryle Walker (darylew_at_[hidden])
Date: 2000-08-02 17:24:15

on 8/1/00 1:39 PM, Howard Hinnant at hinnant_at_[hidden] wrote:

> Daryle Walker wrote on 8/1/2000 1:05 PM
>> My compiler, Metrowerks CodeWarrior Pro 5 for Mac OS (with 5.3 update),
>> allows some types of member templates, but does not allow others.  For
>> instance I couldn't define a "template <typename T> operator T*() const"
>> method for a class I tried to write.  Could we add another #define in
>> config.hpp for this type of compiler limitation (maybe
>> BOOST_NO_TEMPLATE_MEMBER_OPERATORS, but I don't know the exact range of the
>> limitation)?
> 
> This limitation will be lifted in Pro 6 (real soon now).

But that won't help people using CWP 5 now (or still using it when CWP 6
comes out) or any other compiler that may have the same problem.  So we may
need some sort of guard anyway.  The config.hpp file already shields some
errors according to compiler version, so this guard can be done the same
way.

I know the limitation does not let me create generic pointer conversions or
generic member-pointer conversions, but I don't know what other (conversion)
operators it affects.  We would need to know that before establishing any
new BOOST_NO_TEMPLATE_* guard.

On a related note, shouldn't we enforce any hierarchies in the guards?  For
instance, if BOOST_NO_USING_TEMPLATE is defined, all other template-related
guards should be defined, without having to explicitly set every one of
those guards in a compiler listing.  I guess this could come after the
compiler-specific portion.  For example:

#ifdef BOOST_NO_USING_TEMPLATE
#define BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS
#define BOOST_NO_MEMBER_TEMPLATES
#define BOOST_NO_MEMBER_TEMPLATE_FRIENDS
#define BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
#endif

#ifdef BOOST_NO_MEMBER_TEMPLATES
#define BOOST_NO_TEMPLATE_MEMBER_OPERATORS  // my theoretical guard
#endif

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