haskell-mode-hook popup upon return

[developernotes]

Hello,
I recently installed haskell-mode, version 20140309.342 via melpa on Emacs 24.3.50.1 on OS X. I Created the a file, with the following content:

data MyMaybe t = Just t | Nothing

After typing Nothing, I pressed return which triggered my screen to split and showed the help for haskell-mode-hook. It states that the current value is nil. Note that I do not have any customizations to haskell-mode, nor do I have additional haskell emacs packages. Is it correct that this is not the desired behavior?

[ivan-m]

I think you need to choose an indentation mode at least.

[developernotes]

Hi @ivan-m

You are correct, adding (add-hook 'haskell-mode-hook 'turn-on-haskell-simple-indent) resolved the issue. Thanks for the pointer!

[ivan-m]

Maybe we should set a default (probably simple indent) just for cases like this?

[hvr]

@ivan-m iirc there's an issue with circular dependencies between the .el-modules, the customize interface, and the way the indentation is currently integrated in haskell-mode that make it non-trivial to set a default in the current state (or at least would lead to other issues)

[developernotes]

@ivan-m @hvr

Maybe as an alternative, a warning could be issued?

(when (eq nil haskell-mode-hook)
  (message "Please add an indentation hook to haskell-mode-hook"))

[chrisdone]

I did write such a help buffer once that explained the various indentation types, when indentation has not been configured, but maybe it's gone.

[chrisdone]

Oh, wait, the pop-up actually explains all this:

haskell-mode-hook is a variable defined in `haskell-mode.el'.
Its value is (haskell-auto-insert-module-template structured-haskell-mode)

Original value was nil

  This variable may be risky if used as a file-local variable.

Documentation:
Hook run after entering `haskell-mode'.

Some of the supported modules that can be activated via this hook:

   `haskell-decl-scan', Graeme E Moss
     Scans top-level declarations, and places them in a menu.

   `haskell-doc', Hans-Wolfgang Loidl
     Echoes types of functions or syntax of keywords when the cursor is idle.

   `haskell-indentation', Kristof Bastiaensen
     Intelligent semi-automatic indentation Mk2

   `haskell-indent', Guy Lapalme
     Intelligent semi-automatic indentation.

   `haskell-simple-indent', Graeme E Moss and Heribert Schuetz
     Simple indentation.

Module X is activated using the command `turn-on-X'.  For example,
`haskell-doc' is activated using `turn-on-haskell-doc'.
For more information on a specific module, see the help for its `X-mode'
function.  Some modules can be deactivated using `turn-off-X'.

See Info node `(haskell-mode)haskell-mode-hook' for more details.

Warning: do not enable more than one of the three indentation
modes. See Info node `(haskell-mode)indentation' for more
details.

You can customize this variable.

[back]

[chrisdone]

Probably what's missing is a simple line that says how to add such a hook.

[developernotes]

Hi @chrisdone

If it provided what you are showing above in the popup that would be great, unfortunately, this is what is displayed out of the box from the melpa installation:

haskell-mode-hook is a variable defined in `haskell-mode.el'.
Its value is nil

This variable may be risky if used as a file-local variable.

Documentation:
Hook run after entering Haskell mode.
No problems result if this variable is not bound.
`add-hook' automatically binds it.  (This is true for all hook variables.)

You can customize this variable.

Maybe something is out of sync between your version and what is available on melpa?

[hvr]

@developernotes what does M-x haskell-version tell?

(also, does your current haskell-mode version have any pointers into the info manual at all?)

[developernotes]

Hi @hvr
M-x haskell-version prints this for me:

haskell-mode version @VERSION@ (@GIT_VERSION@ @ /Users/nparker/.emacs.d/elpa/haskell-mode-20140309.342/)

The info docs are installed, so section 6 on indentation is visible when viewed.

[ghost]

This issue got me as well. Would have been really nice if after reading that lengthy intro I had any idea how to fix it. Instead I spent 15 minutes thinking I was crazy and almost disabled haskel-mode / renamed my file something other than .hs before stumbling on this page in my 3rd google search. This should really be modifed somehow.
My haskell-version is:
haskell-mode version @Version@ (@GIT_VERSION@ @ /home/russell/.emacs.d/elpa/haskell-mode-20140430.945/)
installed through list-packages and selecting haskell-mode.

[ghost]

For me the issue persists after adding 'structured-haskell-mode to 'haskell-mode-hook. It should not happen because then 'haskell-mode-hook is not nil.

[developernotes]

Hi @sumitsahrawat

Do you get the same behavior if you explicitly include a (require 'shm)?

[ghost]

Yes, it did. But now i'm doing fine with (add-hook 'haskell-mode-hook 'turn-on-haskell-indentation) and have ditched shm.

[stehgold]

For mere mortals like me - where do I have to add this ? Getting only half the screen size is annoying. Here is my .emacs

(custom-set-variables
;; custom-set-variables was added by Custom.
;; If you edit it by hand, you could mess it up, so be careful.
;; Your init file should contain only one such instance.
;; If there is more than one, they won't work right.
'(ansi-color-names-vector ["#2e3436" "#a40000" "#4e9a06" "#c4a000" "#204a87" "#5c3566" "#729fcf" "#eeeeec"])
'(custom-enabled-themes (quote (tsdh-dark))))
(custom-set-faces
;; custom-set-faces was added by Custom.
;; If you edit it by hand, you could mess it up, so be careful.
;; Your init file should contain only one such instance.
;; If there is more than one, they won't work right.
)
(custom-set-variables
'(haskell-mode-hook '(turn-on-haskell-indentation)))

[ghost]

@stehgold You have to add "turn-on-haskell-indentation" to the haskell mode hook.
Instead of using custom set variables, write

(add-hook 'haskell-mode-hook 'turn-on-haskell-indentation)

[stehgold]

Ahh, it's silently auto-indenting now. What a relief... :)

Thank you,
Stephan

[gwern]

Oh, so this is why haskell-mode has been so unbearable for the past year for me!

Oh, wait, the pop-up actually explains all this:

The Debian package seems to include only the less informative popup. I had no idea that it had anything to do with adding an indent-mode.

Actually, I don't think the version you quote is a clear explanation either. I thought I understood Emacs reasonably well, but I don't get anything like "I need to add (add-hook 'haskell-mode-hook 'turn-on-haskell-indentation) to my .emacs to make this popup go away" from that documentation...

[adnelson]

I've added this line to my init.el:

(add-hook 'haskell-mode-hook 'turn-on-haskell-indentation)

And even though I've run M-x eval-buffer, I still get this popup every time I press enter telling me about haskell-mode-hook. This is incredibly obnoxious. What am I not doing to get rid of this?

EDIT:
It seems that the the warning only keeps on popping up on haskell files that were opened before I made the change to my init.el. There's probably a better way to do it, but it seems that closing and reopening the source files I was working on gets the job done.

[gracjan]

Use (add-hook 'haskell-mode-hook 'haskell-indentation-mode) Your version should also work but for some reason it does not. That is a bug.

[gracjan]

@adnelson: Hooks are run when things happen, the hook says to enable haskell-indentation-mode just after haskell-mode is turned on. It does not work retroactively on already open buffer, as you have noticed.