display error message to minibuffer when goto next/prev error.

[notogawa]

When goto-next/prev-error, this PR automatically display error massage in the current line to minibuffer.
Enable us to check the message immediately without open new buffer by M-?.
ghc-init with ghc-display-error-to-minibuffer activate this feature.

[kazu-yamamoto]

This code could be improved.

• M-n is always bound to ghc-goto-next-error.
• defvar ghc-display-error:
• ghc-goto-next-error. changes its behavior according to:
  -- nil is the current behavior
  -- 'minibuf to display error messages to minibuffer
  -- 'other-buffer to display error message to another buffer (as if M-? follows).

[alanz]

On the topic of M-n, would it make sense to have an option to prioritise errors over warnings? Sometimes I have a file with lots of warnings (via -wall) and only one or two errors. I want to sort out the errors first, then the warnings.

[notogawa]

alanz, I think your topic should be another issue.

[kazu-yamamoto]

Looks good. Merged. Thanks.

[kazu-yamamoto]

@alanz Does GHC provide both warnings and errors at the same time? If so, please give an example.

[alanz]

I have seen it on occasion, can't reproduce one now. Will keep my eye out
and report when it happens.

It might be a project wide thing, where if e.g. there is an error in an exe
but and you are editing a lib file. I am basing this on seeing something
like

(Haskell 2:54 ...) in my emacs mode line, indicating 2 errors and 54
warnings

On Sat, Apr 5, 2014 at 1:32 PM, Kazu Yamamoto notifications@github.comwrote:

@alanz https://github.com/alanz Does GHC provide both warnings and
errors at the same time? If so, please give an example.

Reply to this email directly or view it on GitHubhttps://github.com//pull/206#issuecomment-39635505
.

[alanz]

Attached is a screenshot showing the problem. I was editing the file on the right which is imported by most of the rest of the project and provides types, and changed one of the types. The file I was editing (Utils.hs) has no errors, only warnings, but various other files, including the one on the left then have errors.

As you can see in the highlighted area both errors and warnings are reported, although the errors are for the project as a whole. I suspect it relates to the emacs code not properly updating the warning/error count per buffer.

PS, I spent a few minutes trying to reproduce this in a simpler environment without success, I can try again if it is needed

[kazu-yamamoto]

OK. I will make errors come first.

[alanz]

Well, for a given file it will be either warnings or errors. In that
specific case there were warnings in the active file, but errors in the
wider project. So I suspect the current behaviour is fine, the question is
more whether the right information is being displayed in the modeline.

On Tue, Apr 8, 2014 at 12:05 AM, Kazu Yamamoto notifications@github.comwrote:

OK. I will make errors come first.

Reply to this email directly or view it on GitHubhttps://github.com//pull/206#issuecomment-39789824
.