Re: [boost] [cmake] Minimum viable cmakeification for Boost

Subject: Re: [boost] [cmake] Minimum viable cmakeification for Boost
From: Peter Dimov (lists_at_[hidden])
Date: 2017-06-21 10:58:07

Thomas Heller wrote:

> People who prefer declarative builds can stick to Boost.Build.

That's missing the point. Declarative build descriptions are preferable in 
any build system, and any serious use of one leads inevitably to this same 
conclusion. Witness, for instance, how Meson intentionally makes its 
language not Python, even though it's very much Python-looking, and how 
Bazel also has its own language. This is because if the language is Python, 
people are encouraged to program in it, instead of declaring targets.

Target declarations compose, logic that manipulates global environment 
doesn't.

Now it's true that the declarative approach is sometimes less convenient. 
Imperatively, you just check whether zlib is installed, #define or not 
HAVE_ZLIB and build different things based on that. Whereas the alternative 
is to have a separate zlib-support library target, which injects a .cpp file 
into the main program via usage-requirements, which registers the zlib 
support with the main library. But, the upside is that if everyone writes 
their build descriptions properly, you just link to the appropriate targets 
in the root build file and everything "just works".