Bug: Babel: haskell code evaluation inconsistency [7.7 (release_7.7.160.g3e33)]

[Major A <andras.g.major@gmail.com>]

Hi again,

I want to use haskell code blocks in order to evaluate them.  The
problem is that, depending on what haskell interpreters are installed
on the computer, Babel will call a different interpreter to evaluate
the code with.  Also, the haskell interpreter interface appears to be
highly stateful and unreliable.

Here's an example -- ghc6 is installed, but not hugs:

#+begin_src haskell :results output
  import System.IO
  openFile "doesNotExist.ppt" ReadMode
#+end_src

#+results:
: Loading package ghc-prim ... linking ... done.
: Loading package integer-gmp ... linking ... done.
: Loading package base ... linking ... done.

The interesting thing is that this output only occurs on the first run
of the code -- if I hit C-cC-c again, the #+results: section will be
empty.

Now the same source, with hugs installed in addition to ghc6 -- the
source block is the same, but the output is very different:

#+results:
: Type :? for help
: ERROR - Syntax error in expression (unexpected keyword "import")

Again, if I press C-cC-c again, the first line of output ("Type :? for
help") is no longer present.

This is what I suggest:

- Do away with "haskell" as the keyword for haskell code blocks, just
  like graphviz blocks use "dot" instead of simply "graphviz".

- Introduce new keywords -- I propose at least "runghc", "ghci", and
  "hugs".  This is important since there are significant source-level
  differences (see above) between hugs and ghc and even between the
  compiler and interpreter from the same project (ghc and ghci).
  Without these, the progammer will never be able to predict how the
  code is evaluated and which compiler or interpreter they must code
  for.

- Make sure the incorporation of the output or the value is done
  correctly (also see my previous bug report for this).

Enough for today,

  András



Emacs  : GNU Emacs 23.3.1 (i486-pc-linux-gnu, GTK+ Version 2.24.3)
 of 2011-04-10 on raven, modified by Debian
Package: Org-mode version 7.7 (release_7.7.160.g3e33)

current state:
==============
(setq
 org-export-latex-after-initial-vars-hook '(org-beamer-after-initial-vars)
 org-speed-command-hook '(org-speed-command-default-hook org-babel-speed-command-hook)
 org-babel-load-languages '((asymptote . t) (ditaa . t) (dot . t) (gnuplot . t) (haskell . t) (latex . t) (octave . t)
 			  	           (R . t) (ruby . t) (scheme . t) (sh . t))
 org-metaup-hook '(org-babel-load-in-session-maybe)
 org-after-todo-state-change-hook '(org-clock-out-if-current)
 org-babel-tangle-lang-exts '(("ruby" . "rb") ("latex" . "tex") ("haskell" . "hs") ("asymptote" . "asy")
 			    	            ("emacs-lisp" . "el"))
 org-export-blocks-postblock-hook '(org-exp-res/src-name-cleanup)
 org-export-latex-format-toc-function 'org-export-latex-format-toc-default
 org-tab-first-hook '(org-hide-block-toggle-maybe org-src-native-tab-command-maybe org-babel-hide-result-toggle-maybe)
 org-src-mode-hook '(org-src-babel-configure-edit-buffer org-src-mode-configure-edit-buffer)
 org-confirm-shell-link-function 'yes-or-no-p
 org-export-first-hook '(org-beamer-initialize-open-trackers)
 org-agenda-before-write-hook '(org-agenda-add-entry-text)
 org-blank-before-new-entry nil
 org-babel-pre-tangle-hook '(save-buffer)
 org-cycle-hook '(org-cycle-hide-archived-subtrees org-cycle-hide-drawers org-cycle-show-empty-lines
 		  org-optimize-window-after-visibility-change)
 org-export-preprocess-before-normalizing-links-hook '(org-remove-file-link-modifiers)
 org-mode-hook '(#[nil "\300\301\302\303\304$\207" [org-add-hook change-major-mode-hook org-show-block-all append local]
 	          5]
			 #[nil "\300\301\302\303\304$\207"
			          [org-add-hook change-major-mode-hook org-babel-show-result-all append local] 5]
				  		 org-babel-result-hide-spec org-babel-hide-all-hashes)
 org-ctrl-c-ctrl-c-hook '(org-babel-hash-at-point org-babel-execute-safely-maybe)
 org-confirm-elisp-link-function 'yes-or-no-p
 org-export-interblocks '((lob org-babel-exp-lob-one-liners) (src org-babel-exp-inline-src-blocks))
 org-clock-out-hook '(org-clock-remove-empty-clock-drawer)
 org-occur-hook '(org-first-headline-recenter)
 org-from-is-user-regexp nil
 org-export-preprocess-before-selecting-backend-code-hook '(org-beamer-select-beamer-code)
 org-confirm-babel-evaluate nil
 org-export-latex-final-hook '(org-beamer-amend-header org-beamer-fix-toc org-beamer-auto-fragile-frames
 			     			              org-beamer-place-default-actions-for-lists)
 org-metadown-hook '(org-babel-pop-to-session-maybe)
 org-export-blocks '((src org-babel-exp-src-block nil) (comment org-export-blocks-format-comment t)
 		        (ditaa org-export-blocks-format-ditaa nil) (dot org-export-blocks-format-dot nil))
 )