Seperating haskell and cabal mode

[puff-paddy]

Various major modes for haskell exist that are not haskell-mode, (haskell-ts-mode, haskell-ng-mode), and users of both are forced to pull haskell-mode since it provides a major mode for cabal. Would it be practical to support cabal-mode from haskell-mode in its own package?

[purcell]

Probably, yes. The steps we'd need to follow would be approximately the following:

• Create a new repo called cabal-mode with cabal.el, starting out as a copy of haskell-cabal.el.
• Change all the haskell-cabal- identifier prefixes to cabal-.
• Remove the (require 'haskell-utils) and figure out what would break. If anything, fix it if practical.
• Publish a corresponding cabal package on MELPA and/or ELPA.
• Remove haskell-cabal.el from haskell-mode, and perhaps (though probably not) make haskell-mode depend on the cabal package.

This is also relevant to my interests, because I'm personally working with haskell-ts-mode instead of haskell-mode. However, I'm not working much with Haskell at the moment, so I'm unlikely to work on the above steps myself.

[webdevred]

Probably, yes. The steps we'd need to follow would be approximately the following:

* Create a new repo called `cabal-mode` with `cabal.el`, starting out as a copy of `haskell-cabal.el`.

* Change all the `haskell-cabal-` identifier prefixes to `cabal-`.

* Remove the `(require 'haskell-utils)` and figure out what would break. If anything, fix it if practical.

* Publish a corresponding `cabal` package on MELPA and/or ELPA.

* Remove `haskell-cabal.el` from `haskell-mode`, and _perhaps_ (though probably not) make `haskell-mode` depend on the `cabal` package.

This is also relevant to my interests, because I'm personally working with haskell-ts-mode instead of haskell-mode. However, I'm not working much with Haskell at the moment, so I'm unlikely to work on the above steps myself.

I spent a lot of time writing code for my personal projects during the summer. Also it feels like haskell-mode is a big project, it is hard to get a good understanding of it, I dont know where to start. But I would love to get into haskell-mode and I would be like to help with this issue. I can create a new repo, in my account I guess since I dont have haskell organization permissions and separate the cabal mode into that and ping you when I am getting somewhere.

[puff-paddy]

@webdevred how is it going with separating the cabal mode?

[purcell]

That sounds good, @webdevred — ping me if you need anything, or when there's anything to show. In due course we could then fold it back into this org for community maintenance.

[webdevred]

Hello @puff-paddy,
Update from my side:
So far I found three definitions in haskell-utils.el used by haskell-cabal.el, they are
haskell-mode-toggle-interactive-prompt-state along with its toggle variable haskell-mode-interactive-prompt-state and haskell-utils-read-directory-name.

haskell-utils-read-directory-name, however is only used in haskell-cabal-get-dir, a function which is not used inside haskell-cabal.el but it is used in haskell-session.el.

This is is example of where haskell-mode-toggle-interactive-prompt-state is used:

(defun haskell-cabal-find-or-create-source-file ()
  "Open the source file this line refers to."
  (interactive)
  (let* ((src-dirs (append (haskell-cabal-subsection-entry-list
                            (haskell-cabal-section) "hs-source-dirs")
                           '("")))
         (base-dir (file-name-directory (buffer-file-name)))
         (filename (haskell-cabal-line-filename)))
    (when filename
      (let ((candidates
             (delq nil (mapcar
                        (lambda (dir)
                          (let ((file (haskell-cabal-join-paths base-dir
                                                                dir
                                                                filename)))
                            (when (and (file-readable-p file)
                                       (not (file-directory-p file)))
                              file)))
                        src-dirs))))
        (if (null candidates)
            (unwind-protect
                (progn
                  (haskell-mode-toggle-interactive-prompt-state)
                  (let* ((src-dir
                          (haskell-cabal-join-paths base-dir
                                                    (or (car src-dirs) "")))
                         (newfile (haskell-cabal-join-paths src-dir filename))
                         (do-create-p (y-or-n-p (format "Create file %s ?" newfile))))
                    (when do-create-p
                      (find-file-other-window newfile ))))
              (haskell-mode-toggle-interactive-prompt-state t))
          (find-file-other-window (car candidates)))))))

haskell-cabal-find-or-create-source-file is bound to C-c C-f in the cabal mode.

I plan to clean up my code and publish my code later, maybe tomorrow or during the coming week and proceed to make a package in melpa or elpa.

[puff-paddy]

No worries, take your time

[webdevred]

No worries, take your time

Update: I have published my cabal-mode package as a draft, we will probably discuss a bit how to improve it before merging it into melpa.

[puff-paddy]

Since cabal mode has been merged to melpa thanks to @webdevred , are there plans to remove haskell-cabal.el and perhaps add cabal-mode as a dependency

[webdevred]

Since cabal mode has been merged to melpa thanks to @webdevred , are there plans to remove haskell-cabal.el and perhaps add cabal-mode as a dependency

I would be happy help with this part as well, if @purcell thinks we should do this.

[purcell]

Yeah, it would make sense to remove haskell-cabal.el. In a purist sense, haskell-mode shouldn't really depend on the cabal-mode package. Over time, haskell-mode has turned into a big Haskell IDE bundle, which isn't super desirable IMO, and static package dependencies make it hard to swap out non-core portions.