Choose a REPL session target from list

[vlatkoB]

New function haskell-session-choose-target enables choosing from available targets list from .cabal file.
It is just a wrapper around haskell-session-change-target which can still be used to select a target directly, by specifying it as an arg.

[gracjan]

@vlatkoB: almost great!

I think (interactive) can do what you need it to do, look here: http://stackoverflow.com/questions/2382524/adding-completion-to-interactive

• please embed this functionality in an already existing function haskell-session-change-target
• look through haskell-cabal.el and see if there is anything you could use
• put the cabal section enumeration function in haskell-cabal.el
• -mapcar is not good, please find something elisp specific that fulfills the purpose

[vlatkoB]

Almost all requests fulfilled, except the using something from haskell-cabal.el.
Actually, my first attempt used exclusively haskell-cabal functions:

(defun haskell-cabal-extract-targets ()
  "Enumerate targets from .cabal file."
  (interactive)
  (let (matches)
    (goto-char (point-min))
    (haskell-cabal-next-section)
    (while (not (eobp))
      (push (haskell-cabal-section-value (haskell-cabal-section)) matches)
      (haskell-cabal-next-section))
    (reverse matches)))

However, it works correctly only when invoked inside .cabal buffer. When called with with-temp-buffer, results are incorrect.

(defun test-in-temp ()
  (interactive)
  (let ((cabal-file (haskell-cabal-find-file)))
    (when (and cabal-file (file-readable-p cabal-file))
      (with-temp-buffer
    (insert-file-contents cabal-file)
    (print (haskell-cabal-extract-targets))))))

Either I'm blind to some obvious mistake, or functions in haskell-cabal are somehow dependent on "real" .cabal file or something.

I asked on IRC for help, but no answer. I'm very fresh in elisp, and can't solve it without going too deep, for what I currently have no time.

In other words, any help is appreciated.

[gracjan]

I just tested the two functions that you've put here and those work (well, almost). I get all the answers plus some additional things.

• please use haskell-cabal-source-bearing-sections to only find things that can be a target

[vlatkoB]

If you mean the functions in the post above, the result is not correct. Not only there are more results than needed, but the result for test is prefixed with -suite.
("-version: >=1.20" "-type: Simple" "biblio" "biny" "-suite test1" "-suite test2" "benchy")

The result of the function should be the same when in the buffer with .cabal file, and when using with-temp-buffer. Input is the same, so should be the output. I don't trust it. Too much IO. :-)
At least until I find out what's causing the differences.

Can the author of haskell-cabal maybe comment the issue?

[gracjan]

If you look into haskell-cabal-mode-syntax-table you will find:

    (modify-syntax-entry ?- "w"  st)

That says that in buffers where haskell-cabal-mode is enabled - char should match \\w regexp. If buffer is not in haskell-cabal-mode minus char is not word character so it does not match.

[vlatkoB]

It is working now. Changed major-mode of temp buffer to haskell-cabal-mode.
Can you test on your side?

[gracjan]

Works for me. Please clean up two more things and we are good to go.

[vlatkoB]

What defvar are you talking about?
There was one in previous commit to satisfy tests, but none in this commit. In this commit I merged two functions in above post and replaced the previous haskell-cabal-enum-targets function, as the commit message says.

[gracjan]

There are two commits in this pull request. defvar is in line 449 of the first one.

[vlatkoB]

I'm a little lost. Could use a little help.

[gracjan]

It was me who was lost, everything is fine.

I have one more request though: can you make it use its own separate history variable? Have a read here:

http://www.gnu.org/software/emacs/manual/html_node/elisp/Minibuffer-Completion.html

There is an argument called history and it defaults to minibuffer-history. This is suboptimal, better is to use special history variable for cabal targets, lets say haskell-cabal-targets-history.

Can you do this?

[vlatkoB]

Can you check?

[gracjan]

@vlatkoB: Can you fix these two small things? Your pull request is valuable and it is a shame that it wait in queue.

[vlatkoB]

@gracjan They were fixed the day you asked for them. haskell-cabal-targets-history to symbol above.

[gracjan]

Fixes #817