D based build system to replace current makefile

[Nick Sabalausky]

On Thu, 30 May 2013 00:49:57 -0700
Timothee Cour <thelastmammoth at gmail.com> wrote:

> We should move to a D-based build system to build
> dmd/druntime/phobos/d-programming-language/tools.
> 
> Reasons, in case it's not obvious:
> 
> 1) DRY: makefile is full of repetitions
> 2) cross platform: different makefiles for different architectures are
> needed (even win32 vs win64!)
> 3) safety: makefile happily ignores that $VAR variables are not set,
> and can create havoc; likewise tools/update.sh is a bash script and
> may not stop on 1st error.
> 4) tools/update.sh doesn't work out of the box on OSX last i checked
> (I made a pull request for that some time back:
> https://github.com/timotheecour/d-programming-language.org/commit/557a2befa74ddfe99ee5c0e12e7c3d028f27d276)
> 
> Even a bad D-based build system will be better than a makefile, but
> it's not hard to write a reasonable one at least for the particular
> task of building dmd/druntime/phobos/d-programming-language/tools.
> It'll lower the entry point for people to contribute to dmd/phobos by
> making rebuilding trivial.
> 
> Here's how it'd work:
> 
> 1) a mixed D-based/makefile build that'll work 'from scratch' via
> bootstrapping:
> 1a) dmd: first uses a makefile to build dmd+druntime
> 1b) rdmd built from a D file using dmd
> 1c) phobos, d-programming-language, tools built from a D file using
> rdmd
> 
> 2) a pure D-based build that'll work using an existing dmd binary (eg
> distributed binary)
> that's the one most will use.
> 

FWIW, phobos needs to be built before rdmd because rdmd relies on
phobos.

Also, while I like the idea of replacing makefiles with a D solution,
I'm unsure whether it's really a good idea because that may make it
more difficult to bootstrap DMD to run on new platforms.

However, I do think that wrapping the invocations of all the makefiles
is a good idea and would still have the benefit of making it harder to
make mistakes such as (like you said) setting up the %VARs wrong.

In fact I've started working on such stuff already (And DVM can
already compile DMD, too, although it's possible it may still have
some room for improvement).