[Haskell-community] [Haskell-cafe] technical thoughts on stack

[Simon Marlow]

How would I use stack with a GHC 8.0.2 release candidate?

On 13 September 2016 at 21:27, Christopher Allen <cma at bitemyapp.com> wrote:

> Stack is not your shell, a build script, or a Makefile. It already has
> path management for the GHC installations it provisions and supports.
> It is not Stack's job to mutilate your path to support external GHC
> installations.
>
> Make a Makefile or add shortcuts to your bashrc to switch compilers.
>
> On Tue, Sep 13, 2016 at 3:16 PM, Paolo Giarrusso <p.giarrusso at gmail.com>
> wrote:
> > On Tuesday, September 13, 2016 at 10:05:44 PM UTC+2, Christopher Allen
> > wrote:
> >>
> >> Stack users are moving away from enabling system installed GHCs by
> >> default because it breaks the ease of enabling profiling for libraries
> >> when you're using a Stack-installed GHC.
> >
> >
> >>
> >> I'm not sure why multiple system-installed GHCs needs to be supported
> >> in addition to the GHC support Stack already provides. That's extra
> >> work for...what? Stack isn't trying to compete with Nix. It's more
> >> like a blend of rustup and cargo -- or Clojure's Leiningen.
> >
> >
> > To clarify: I'm not proposing stack to install those GHCs, just to use
> them.
> >
> > I think the extra work would be limited (calling GHC-X.Y.Z instead of
> GHC)
> > and has other technical advantages
> > (https://github.com/commercialhaskell/stack/issues/2433). Mind you, I'm
> > willing to contribute the work and not asking anybody—I've just been
> busy.
> >
> > Right now I have to modify the PATH every time I use GHC 7.8.4 because I
> > needed to customize the build (I'm on OS X 10.11), but I still want GHC
> 8 by
> > default.
> >
> >>
> >> On Tue, Sep 13, 2016 at 3:01 PM, Paolo Giarrusso <p.gia... at gmail.com>
> >> wrote:
> >> >
> >> >
> >> > On Tuesday, September 13, 2016 at 9:47:20 PM UTC+2, Richard Eisenberg
> >> > wrote:
> >> >>
> >> >> Thanks, many, for explaining better ways to interact directly with
> GHC
> >> >> after using a `stack setup`. Perhaps, then, all that’s stopping
> someone
> >> >> like
> >> >> me from liking the ease of `stack setup` is a little missing PR (as
> in,
> >> >> public relations). I understand that many people want to keep GHC
> >> >> cloistered
> >> >> away to ease version swapping, but others (like me) want GHC
> available
> >> >> front
> >> >> and center.
> >> >>
> >> >> Other minor points:
> >> >> `stack env` does not work for me: my version of stack does not know
> how
> >> >> to
> >> >> `env`.
> >> >
> >> >
> >> > That's correct—stack env was a feature request.
> >> >
> >> > The warning on `stack ghci` doesn't happen usually, but I'd say
> that's a
> >> > bug
> >> > (probably because it's a new install)?
> >> >
> >> > I use stack (and have contributed a bit recently), but I agree
> there's a
> >> > few
> >> > things stack could do better for this workflow.
> >> >
> >> > And the transition has a rather annoying learning curve—stack ghci and
> >> > stack
> >> > ghc are not the same as ghci/ghc. I think that's on purpose to
> support a
> >> > project-based workflow, and it has upsides, but it's a transition
> >> > pitfall.
> >> >  Lots of things *are* explained in
> >> > https://docs.haskellstack.org/en/latest/faq/, but you do need learn a
> >> > few
> >> > things from scratch.
> >> >
> >> > You want stack exec ghc and stack exec ghci, and arbitrary options
> >> > require a
> >> > double dash `--` — use `stack ghc -- --version` or `stack exec -- ghc
> >> > --version`. And I'm afraid the command syntax is mostly frozen by now.
> >> >
> >> > To support a compiler-based workflow, there are a few things planned—I
> >> > opened an issue to collect them, starting from Simon Marlow's recent
> >> > email:
> >> > https://github.com/commercialhaskell/stack/issues/2546
> >> >
> >> > BTW, a system-installed GHC already works if you stick to one (and
> only
> >> > build projects that need that). But I'd love to support multiple
> >> > system-installed GHCs and being able to pick the one you need.
> >> >
> >> > As others already explained, giving access to stack-installed GHCs can
> >> > be
> >> > problematic—they're going to work, in part, exactly because you can't
> >> > install in their package database.
> >> >
> >> > Having stack install system-wide GHCs would IMHO risk opening a can of
> >> > worms—having working binaries for all Linux distros requires some
> work,
> >> > system installers would be harder and most users would dislike them.
> >> >
> >> > _______________________________________________
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> >>
> >> --
> >> Chris Allen
> >> Currently working on http://haskellbook.com
> >> _______________________________________________
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>
>
>
> --
> Chris Allen
> Currently working on http://haskellbook.com
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