Does ghci mode recognize cabal sandboxes?

[fosskers]

Forgive me if this has been asked before, or if the solution is trivial. I'd like to be able to install libraries in a sandbox, then play with them in an emacs session without making a full cabal project (similar to this post on stackoverflow).

Is this possible?

[purcell]

Just tried this now:

• cabal sandbox init in a fresh dir
• cabal install whatever as needed
• create a foo.hs file in that directory, but no foo.cabal file
• Use C-c C-l to load the foo.hs file, forcing haskell-mode to create an inferior haskell process

The result: haskell-mode prompts to start a cabal repl in that directory, and just hitting return to accept the defaults got me a repl in which the installed library was accessible.

So yes, it's possible.

[fosskers]

Configured emacs to have haskell-process-type as auto by default. When I try the same thing as you did above I get (from my haskell-process-log):

Starting inferior `cabal repl' process using cabal ...
-> :set prompt "\4"
-> Prelude.putStrLn ""
-> :set -v1
<- Package has never been configured. Configuring with default flags. If this
   fails, please run configure manually.

<- cabal:
<-  No cabal file found.
   Please create a package description file <pkgname>.cabal

Event: "exited abnormally with code 1                                                                                                                          
"                                                                                                                                                              

Process reset.

[purcell]

Hmm, not sure why you saw different results. I'll reopen this, then, until we've figured it out.

My process log looks similar, but without the abnormal exit:

Starting inferior `cabal repl' process using cabal ...
-> :set prompt "\4"
-> Prelude.putStrLn ""
-> :set -v1
<- GHCi, version 7.8.3: http://www.haskell.org/ghc/  :? for help

<- Loading package ghc-prim ... linking ... done.
   Loading package integer-gmp ... linking ... done.

<- Loading package base ... linking ... done.

<- Prelude> 
<- �
   ��
-> :load "/tmp/cabalfu/Foo.hs"
<- [1 of 1] Compiling Foo              ( /tmp/cabalfu/Foo.hs, interpreted )

<- Ok, modules loaded: Foo.
   �
-> :load "/tmp/cabalfu/Foo.hs"
<- [1 of 1] Compiling Foo              ( /tmp/cabalfu/Foo.hs, interpreted )
   Ok, modules loaded: Foo.
   �
-> :!cd /private/tmp/cabalfu/ && cabal build
<- Package has never been configured. Configuring with default flags. If this
   fails, please run configure manually.

<- cabal: No cabal file found.
   Please
<-  create a package description file <pkgname>.cabal
   �
-> :load "/tmp/cabalfu/Foo.hs"
<- [1 of 1] Compiling Foo              ( /tmp/cabalfu/Foo.hs, interpreted )

   /tmp/cabalfu/Foo.hs:3:1: Warning:
       The qualified import of ‘Text.Regex.PCRE.Light’ is redundant
         except perhaps to import instances from ‘Text.Regex.PCRE.Light’
       To import instances alone, use:

[fosskers]

I'm working with a fresh git clone, too. From my .emacs. Nothing looks amiss:

;; Haskell mode                                                              
  (add-to-list 'load-path "/usr/share/emacs/site-lisp/haskell-mode/")
  (require 'haskell-mode-autoloads)
  (add-to-list 'Info-default-directory-list "/usr/share/emacs/site-lisp/haskell-mode/")
;;  (add-hook 'haskell-mode-hook 'turn-on-haskell-doc-mode)                    
  (add-hook 'haskell-mode-hook 'interactive-haskell-mode)
  (add-hook 'haskell-mode-hook 'turn-on-haskell-indentation)
  (custom-set-variables
  '(haskell-process-suggest-remove-import-lines t)
  '(haskell-process-auto-import-loaded-modules t)
  '(haskell-process-log t))
;;  '(haskell-process-type 'ghci))                                             
  (define-key haskell-mode-map (kbd "C-c C-l") 'haskell-process-load-or-reload)
  (define-key haskell-mode-map (kbd "C-c h b") 'haskell-interactive-bring)
  (define-key haskell-mode-map (kbd "C-c C-t") 'haskell-process-do-type)
  (define-key haskell-mode-map (kbd "C-c C-i") 'haskell-process-do-info)
  (define-key haskell-mode-map (kbd "C-c C-c") 'haskell-process-cabal-build)
  (define-key haskell-mode-map (kbd "C-c C-k") 'haskell-interactive-mode-clear)
  (define-key haskell-mode-map (kbd "C-c c") 'haskell-process-cabal)
  (define-key haskell-mode-map (kbd "SPC") 'haskell-mode-contextual-space)

I specify the load path at the top because it's a -git version of the haskell-mode Arch linux package, and it won't work unless I do.

[fosskers]

Steps:

1. Made a sandbox in a fresh directory.
2. Did cabal install shelly.
3. Made the following file:

module ShellyTest where

import Shelly

1. Checked haskell-process-type. It is auto.
2. C-c C-l
   • Start a new project named "haskell"? y
   • RET to the next three questions.
3. Haskell process dies. Log is:

Starting inferior `cabal repl' process using cabal ...
Starting inferior `cabal repl' process using cabal ...
-> :set prompt "\4"
-> Prelude.putStrLn ""
-> :set -v1
<- Package has never been configured. Configuring with default flags. If this
   fails, please run configure manually.

<- cabal
<- : No cabal file found.
   Please create a package description file <pkgname>.cabal

Event: "exited abnormally with code 1"                                                                              

Process reset.

1. haskell-process-type is still auto. Switched it to ghci.
2. Haskell process starts, but can't find the library.

[ivan-m]

Did you do a cabal configure like the error suggested?

And do you have a .cabal file listing Shelly as a dependency?

[fosskers]

No to both. The idea is that I just want to be able to make a new directory, lay down a sandbox, install some one-shot libraries, and play with them with ghci as the haskell-process-type and not worry about .cabal files. This seemed to work fine for @purcell but not for me.

[ivan-m]

OK, I just tried it, and it works for me (and I have haskell-process-type set to cabal-repl because I forgot to put it on auto after that was introduced; but putting it back to auto didn't change anything.)

Maybe try with a minimal config for emacs to check this?

As a comparison, here's my log:

Starting inferior `cabal repl' process using cabal ...
-> :set prompt "\4"
-> Prelude.putStrLn ""
-> :set -v1
<- GHCi, version 7.8.3: http://www.haskell.org/ghc/  :? for help

<- Loading package ghc-prim ... 
<- linking ... done.
   Loading package integer-gmp ... linking ... done.
   Loading package base ... linking ... done.
   Prelude> �
-> :load "/tmp/testing/test.hs"
<- 

<- ��[1 of 1] Compiling Testing          ( /tmp/testing/test.hs, interpreted )

<- 
   /tmp/testing/test.hs:3:1: Warning:
       The import of ‘Shelly’ is redundant
         except perhaps to import instances from ‘Shelly’
       To import instances alone, use: import Shelly()
   Ok, modules loaded: Testing.
   �

[fosskers]

Still isn't working, and this is all I have in my .emacs:

(add-to-list 'load-path "/usr/share/emacs/site-lisp/haskell-mode/")
(require 'haskell-mode-autoloads)
(add-to-list 'Info-default-directory-list "/usr/share/emacs/site-lisp/haskell-mode/")
;;  (add-hook 'haskell-mode-hook 'turn-on-haskell-doc-mode)                    
(add-hook 'haskell-mode-hook 'interactive-haskell-mode)
(add-hook 'haskell-mode-hook 'turn-on-haskell-indentation)
(custom-set-variables
 '(haskell-process-suggest-remove-import-lines t)
 '(haskell-process-auto-import-loaded-modules t)
 '(haskell-process-log t))
(define-key haskell-mode-map (kbd "C-c C-l") 'haskell-process-load-or-reload)
(define-key haskell-mode-map (kbd "C-c h b") 'haskell-interactive-bring)
(define-key haskell-mode-map (kbd "C-c C-t") 'haskell-process-do-type)
(define-key haskell-mode-map (kbd "C-c C-i") 'haskell-process-do-info)
(define-key haskell-mode-map (kbd "C-c C-c") 'haskell-process-cabal-build)
(define-key haskell-mode-map (kbd "C-c C-k") 'haskell-interactive-mode-clear)
(define-key haskell-mode-map (kbd "C-c c") 'haskell-process-cabal)
(define-key haskell-mode-map (kbd "SPC") 'haskell-mode-contextual-space)
(global-set-key (kbd "C-c h r") 'haskell-process-restart)

[fosskers]

Any word on this?

[ivan-m]

Just to confirm: by a "fresh git clone" you mean of the haskell-mode repository?

What I've done:

• Copy your init setup into a fresh file; change the haskell-mode directories to being to where mine is (/home/ivan/.emacs.d/elpa/haskell-mode-20141223.1144).
• Change the require to load (as it didn't work otherwise)
• emacs -Q test.emacs.el &
• cd /tmp/ && mkdir test-shelly && cd test-shelly
• cabal sandbox init && cabal install shelly
• In emacs, C-x C-f /tmp/test-shelly/Test.hs
• Put in the contents of the file, save
• Hit C-c C-l
• Choose y, then hit Enter three times
• Prompt appears
• Can now successfully do stuff with Shelly

How are you installing your haskell-mode? You sure you don't have an old version? I'm using MELPA (haven't updated for a while if you notice my load-path change above) and it works.

[fosskers]

Okay, changing require to load didn't do anything for me. Still dies with the same error. I install this via the Arch Linux AUR package emacs-haskell-mode-git, which has the following install script:

pkgname=emacs-haskell-mode-git
pkgver=20120523
pkgrel=1
_gitname="haskell-mode"
_gitnamebranch="haskell-mode"
_gitroot="git://github.com/haskell/$_gitname"
pkgdesc="Haskell syntax highlighting, etc. for GNU Emacs"
arch=('any')
url="https://github.com/haskell/$_gitname"
depends=('emacs')
makedepends=('git')
license=('GPL')
provides=('emacs-haskell-mode')
conflicts=('emacs-haskell-mode')
install=$pkgname.install

build() {
  # create persistent build directory
  mkdir -p $startdir/src

  cd $startdir/src

  if [[ -d $_gitnamebranch ]]; then
    cd $_gitnamebranch
    git clean -dxf
    git reset --hard
    msg "Pulling from GIT server..."
    git pull --rebase
  else
    git clone --depth 1 $_gitroot $_gitnamebranch
    cd $_gitnamebranch
    git pull --rebase
  fi

  # generate the haskell-mode-autoloads.el file and also execute byte compilation
  make all
}

package() {
  # create destination path
  install -d $pkgdir/usr/share/emacs/site-lisp/$_gitnamebranch
  # copy over all files into path
  cp -r $startdir/src/$_gitnamebranch/* $pkgdir/usr/share/emacs/site-lisp/$_gitnamebranch
}

[fosskers]

Also just tried your method, by uninstalling the Arch package and linking instead to my elpa version.

  ;; Haskell mode                                                                                                                                              
  (add-to-list 'load-path "/home/colin/.emacs.d/elpa/haskell-mode-20141230.1141")
  (load "haskell-mode-autoloads.el")
  (add-to-list 'Info-default-directory-list "/home/colin/.emacs.d/elpa/haskell-mode-20141230.1141")
;; etc ...

... and it still dies with the same error, following the same steps you did.