[ANNOUNCE] Shaking up GHC

[Andrey Mokhov]

Simon,

> As I understand it, it can work side-by-side with the existing build
> system, correct?  That means we don't need to make an either/or
> choice, which is very helpful.

That's correct. Note though that the two build systems put (some) build results in the same directories, e.g. inplace/bin/ghc-stage1, so there is some interaction between them. In future it would be possible to decouple them completely (if need be).

> How can I do that using Shake to build?  Maybe
>	sh validate --shake --fast --no-clean
> or something?  Just modifying the validate script to make it
> convenient to use shake for the build part would be great.

This may be possible precisely because binaries are where validate expects them to be. I tried to pull this off, but unsuccessfully so far (validate starts rebuilding everything from scratch with make). I think the reason is that we changed some naming conventions for directories (using stageN instead of dist, dist-boot, dist-install), so validate can't find some utils. I'll let you know if I find a workaround. Otherwise we'll just have to wait for the proper implementation of the "test" target in the new build system. Maybe it's not too difficult to implement.

Ben,

> > But User.hs is a source file, which we shouldn't normally modify lest 
> > we accidentally commit it. Could we have a non-source file to modify 
> > (rather like build.mk being based on build.mk.sample)
> >
> One way around this would be to add User.hs to .gitignore. That way git
> will ignore changes to this files when you `git commit -a`. You can still,
> however, commit changes to it if you ask git explicitly.

Yes, I was thinking about the same idea. 

Cheers,
Andrey

-----Original Message-----
From: Simon Peyton Jones [mailto:simonpj at microsoft.com] 
Sent: 25 January 2016 12:14
To: Andrey Mokhov <andrey.mokhov at newcastle.ac.uk>; ghc-devs at haskell.org
Cc: Neil Mitchell <ndmitchell at gmail.com>; Simon Marlow <marlowsd at gmail.com>
Subject: RE: [ANNOUNCE] Shaking up GHC

Very good.

As I understand it, it can work side-by-side with the existing build system, correct?  That means we don't need to make an either/or choice, which is very helpful.

Every day I do
	sh validate --fast --no-clean
How can I do that using Shake to build?  Maybe
	sh validate --shake --fast --no-clean
or something?  Just modifying the validate script to make it convenient to use shake for the build part would be great.

You say: The make-based build system uses mk/build.mk to specify user build settings. We use src/Settings/User.hs for the same purpose. Feel free to experiment following the Haddock comments.

But User.hs is a source file, which we shouldn't normally modify lest we accidentally commit it.  Could we have a non-source file to modify (rather like build.mk being based on build.mk.sample)

Simon

|  -----Original Message-----
|  From: Andrey Mokhov [mailto:andrey.mokhov at newcastle.ac.uk]
|  Sent: 22 January 2016 14:27
|  To: ghc-devs at haskell.org
|  Cc: Simon Peyton Jones <simonpj at microsoft.com>; Neil Mitchell  
| <ndmitchell at gmail.com>; Simon Marlow <marlowsd at gmail.com>
|  Subject: [ANNOUNCE] Shaking up GHC
|  
|  Dear GHC developers,
|  
|  I am happy to announce that the Shaking up GHC project has finally  
| reached the first milestone. The goal of the project is to design a  
| new GHC build system based on Shake that will eventually replace the  
| current make-based one. See the project page for more details:
|  https://github.com/snowleopard/shaking-up-ghc.
|  
|  There is still a long way until we can match the capabilities of the  
| current build system. At the moment we only build vanilla way.
|  Validation, documentation, build flavours and cross-compilation are  
| not yet implemented. Known limitations are listed here:
|  https://github.com/snowleopard/shaking-up-ghc#current-limitations.
|  
|  The purpose of this announcement is to attract alpha testers and  
| collect early feedback across multiple platforms and build  
| configurations. We already have several success reports on Linux, OS  
| X, Solaris and Windows. However, things will inevitably break and we  
| hope to catch and fix as many of these cases as possible with your  
| help. The instructions on how to try the new build system can be found
|  here: https://github.com/snowleopard/shaking-up-ghc#your-first-build.
|  
|  We plan to be ready to become a part of the GHC tree around 1 March  
| 2016, and catch up with the make build system around 1 June 2016. The  
| dates are tentative and depend on how much time it takes us to resolve  
| the remaining issues: https://github.com/snowleopard/shaking-up-
|  ghc/milestones.
|  
|  I would like thank everyone who contributed to this project so far:
|  Simon Peyton Jones, Neil Mitchell and Simon Marlow came up with the  
| idea and guided me throughout the project; Moritz Angermann, Ben  
| Gamari, Karel Gardas, David Luposchainsky, and Neil Mitchell  
| contributed to the codebase. Thank you all!
|  
|  Kind regards,
|  Andrey