CODEWITHSUNDEEP
haskellemacsorg-modeliterate-programmingorg-babel
Mittenchops
Mittenchops

Reputation: 19674

How to set up org-babel for Haskell with Stack

I'm running:

I've looked through:

While the gist above looks promising, I haven't found anything that looked to be an authoritative way to get org-haskell running (eg, nothing on melpa), and certainly nothing aimed specifically at whatever intricacy running a stack environment rather than using my global ghc would entail.

When I try to:

#+BEGIN_SRC haskell
let x = "test"
putStrLn x
#+END_SRC

I get

executing Haskell code-block

...which hangs forever. When I C-g, I see:

GHCi, version 7.6.3: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Some flags have not been recognized: prompt2, ghci     | 
ghci    λ> let x = "TESTING!"
putStrLn x
"org-babel-haskell-eoe"
Prelude| 
<interactive>:4:1: parse error on input `putStrLn'
ghci    λ> "org-babel-haskell-eoe"

When I tab to the haskell buffer, I see it has genuinely evaluated what I sent, it just has this org-babel-haskell-eoe error and never returns control to my org session.

Any chance this is because I have a custom prompt? Using the lambda instead of Prelude> ?

Upvotes: 19

Views: 4815

Answers (4)

appomsk
appomsk

Reputation: 162

In my case it was .ghci, like Testare's. As soon as I commented out :set prompt "λ ", emacs stopped freezing but gave the message ‘org-babel-script-escape’ expects a string. It was necessary to comment out :set +t for it to work.

Upvotes: 2

Azriel
Azriel

Reputation: 407

what i did after installed stack and ghci (with stack itself)), was to install intero in emacs and then add those to init.el: 

 (setq haskell-process-type 'stack-ghci)
 ((org-babel-do-load-languages
     'org-babel-load-languages
        '((haskell . t)))

after that i can C-c C-c in haskell code block and i get a result under the code block.

Upvotes: 1

Testare
Testare

Reputation: 378

It is probably because of the custom prompt: I had the same issue, and when I removed ":set +t" and ":set prompt "GHCI >" from ~/.ghci, it worked. I fiddled with it some, and it seems it will work so long as your custom prompt doesn't have any spaces in it except the end (I changes mine to "GHCI> " and it works). It seems to be that the regular expression it parses the information from assumes the prompt will have no spaces in it.

Upvotes: 2

NickD
NickD

Reputation: 6412

This is not a complete answer: in particular, it does not even mention Stack. But I (a complete ignoramus on Haskell) wanted to find out what it would take to get the OP's test program to run in babel. Here's what I found:

  • You need a haskell interpreter ;-) I'm on Fedora 24, so I installed the ghc-compiler package and I got ghci.

  • You need haskell-mode. I installed that from MELPA, using the emacs package manager. That also installed inf-haskell.el

  • By default, inf-haskell wants to run hugs, so I customized haskell-program-name and set it to "ghci".

  • M-x load-library RET ob-haskell RET

  • C-c C-c on the code block: the first time it fails and the Messages buffer shows "Buffer haskell.org does not exist or has no process".

  • But if you do it C-c C-c on the code block again, it succeeds!

Obviously, ob-haskell.el needs some work - and that's before we even get to Stack, of which I know even less than I know of Haskell, so I'll leave that as an exercise for the interested reader :-)

EDIT: Re. version info (requested in a comment): I keep close to the bleeding edge. At this point in time (2017-05-01), I run Org mode version 9.0.5 (release_9.0.5-444-g998576 @ /home/nick/elisp/org-mode/lisp/) and GNU Emacs 26.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.20.10) of 2017-04-14

Upvotes: 6

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