Compiler blacklist 'shorthand'

[Ryan Schmidt]

On May 5, 2018, at 19:36, Craig Treleaven wrote:

> A couple of times recently, I’ve noticed boilerplate in ports that require C++14.  After including the compiler_blacklist_versions portgroup, they then do some gymnastics like:
> 
> compiler.blacklist          *gcc-3.* *gcc-4.* {*gcc-5.[0-3]} \
>                            {clang < 800} macports-clang-3.4 macports-clang-3.5 macports-clang-3.6 macports-clang-3.7
> 
> Would it not be easier to use and maintain if we had some shorthand definitions.  Maybe something like:
> 
> compiler.blacklist      ${min_cxx14}
> 
> “min_cxx14” would be defined in the portgroup and then expand to the above...assuming the above actually does a good job of blacklisting compilers that don’t support C++14!
> 
> A major advantage is that if our list of non-C++14 compilers ever changes, it only needs to be updated in one spot.
> 
> I suspect there would be a few other shorthand lists that could be pre-defined.
> 
> Thoughts?

Yes, we should have support for specifying the required language standard(s) in Portfile, so that MacPorts could then select a compatible compiler.

Until we have that, you need to blacklist incompatible compilers.

If you require C++11, include the cxx11 1.1 portgroup which will do what's needed for you, including blacklisting incompatible compilers and ensuring the right C++ standard library is used.

If you require C++14, include the cxx11 1.1 portgroup and additionally use "compiler.blacklist-append {clang < 602}".

I'm not familiar with the capabilities or functionality of the languages 1.0 portgroup.