Broken indentation in Emacs 24.5

[jstolarek]

I recently updated my Emacs installation to version 24.5.1 and discovered that in haskell mode upon entering a new line indentation behaves in an unexpected and unintuitive way. In these examples below X shows where the point is set upon pressing Enter at the end of previous line and Y shows where it used to be set before upgrading Emacs:

module Foo where
Y   X

foo :: Bool
Y      X

data A = A

Y      X

instance Foo a where
    bar A A = A
    Y       X

Using haskell-mode just became extremely annoying :| I am using haskell-mode from melpa, version 20151202.34 (ie. today's build).

[jstolarek]

Oh, and this behaviour happens consistently on two different machines. Both have Emacs 24.5.1 compiled from sources, haskell-mode from melpa and this configuration file.

[gracjan]

Remove this line: (add-hook 'haskell-mode-hook 'turn-on-haskell-indent) restart. It should help.

[jstolarek]

Indeed, that changes indentation behaviour, but it does not restore previous, correct behaviour. For example, indentation of case alternatives does not work in a reasonable way. Also, if I have:

foo :: Bool
X

where X represents mark, I would expect that pressing TAB will insert foo. But after commenting out that configuration line it doesn't.

So I would say that what you've given me is a workaround that restores reasonable indentation behaviour at the price of loosing functionality. Thank you for that, but it is not the final solution I am looking for.

[gracjan]

It seems we should reopen #208.

[jstolarek]

Closed means fixed?

[gracjan]

You seem to have found a way to make indentation work so I guess this part is fixed.

There is the unimplemented feature of haskell-indentation-mode that is present in haskell-indent-mode that is symbol completion.

You are the second person requesting that and I'm not sure if this is an expected feature or not. Anyway we will need a volunteer to implement it.

[gracjan]

Anyway submitted as separate issue #1027.

[jstolarek]

You seem to have found a way to make indentation work so I guess this part is fixed.

No, I have not been able to restore previous functionality in a reasonable way, ie. after disabling indentation the problem went away but so did useful functionality. So in no way is my problem solved :( Perhaps this is a duplicate of #208 (as you've pointed out), but in such case please re-open #208.

You are the second person requesting that and I'm not sure if this is an expected feature or not.

I believe I am not requesting any new feature. Completing function name has been present in haskell-mode since I started using it ~3 years ago.

[gracjan]

Opened as #1027.

[jstolarek]

Ok, clearly there is something I don't understand here. From reading #1027 I understand that so far I have been using haskell-indent. After updating Emacs to 24.5 behaviour of haskell-indent is broken and I was forced to turn it off (obviously, losing its functionality). #1027 mentions something about haskell-indentation. Is haskell-indentation a replacement of haskell-indent? Is haskell-indent deprecated or unmaintained and should not be used?

[gracjan]

Your understanding is about correct. haskell-indentation is next attempt at indentation mode after haskell-indent. So far haskell-indentation code has been proved to be more readable and maintanable, at least compared to haskell-indent. Although haskell-indent is not deprecated I think it will be a problem to find a brave soul to fix issues with that indetation mode. Currently all the effort goes into haskell-indentation.

[jstolarek]

Now it makes sense. Thanks. I'll switch to haskell-indentation and hope someone implements #1027

[PierreR]

Wouldn't be clearer to remove haskell-indent completely ? It is not maintained and broken. What's the point keeping it knowing there is no contributor out there to work on it.

I personally would vote for a single indentation scheme that works well (instead of 3 broken option).

The way I understand it is that the initial creator/contributor of haskell-indent is gone without caring for the transition. So it is fair to say haskell-indent is dead IMHO.

[gracjan]

@PierreR: We are slowly getting there. It is time to reduce the number from three to two by removing haskell-simple-ident in #958.