Consider limit codebase max line length to 80/100 via default formatting

[jneira]

• Limit the line length is a usual convention that helps to read the codebase (see serokell haskell style guide f.e: https://github.com/serokell/style/blob/master/haskell.md#line-length, but many other style guides recommend it):

You should keep maximum line length below 80 characters. If necessary, you may use up to 100 characters, although this is discouraged. You should wrap imports at 100 characters.

It would suppose reach a consensus and start to progresively apply it in dedicated pr's, trying to dont disturb existing work in progress. I hope stylish-haskell will support it.

//cc @Ailrun, as you have worked fantastically in the formatting of the codebase

[colonelpanic8]

Not a regular contributor (yet) but my preference would be towards the lower side of this (80 chars), but seeing as there are quite a few places in the code base that exceed this quite a lot, I would also be happy to see any limit 100 chars or less.

[michaelpj]

Allegedly, it already is: https://github.com/haskell/haskell-language-server/blob/master/.editorconfig#L14

[jneira]

Uh, thanks, i forgot about that, unfortunately you have to install an extension in vscode to enable it (and i think other editor does not honour it by default neither)
We have good parts of the code base imported from other repos, written without that file.

[Ailrun]

I believe the current stylish-haskell already uses 80 column limit, so AFAIK our codebase is already formatted with 80 column limit in the cases stylish-haskell can handle. Do you know some specific example of out-of-80-column case?

[colonelpanic8]

@Ailrun I dived in to the code base for the first time yesterday and started reading the "AtPoint.hs" file of ghcide. There were too many lines over 100 chars to count. Here are some examples:

128 chars:

haskell-language-server/ghcide/src/Development/IDE/Spans/AtPoint.hs

Line 122 in 903fe64

rows <- liftIO $ findReferences hiedb True (nameOccName name) (Just $ moduleName mod) (Just $ moduleUnitId mod) exclude

125 chars:

haskell-language-server/ghcide/src/Development/IDE/Spans/AtPoint.hs

Line 127 in 903fe64

refs <- liftIO $ findTypeRefs hiedb True (nameOccName name) (Just $ moduleName mod) (Just $ moduleUnitId mod) exclude

120 chars:

haskell-language-server/ghcide/src/Development/IDE/Spans/AtPoint.hs

Line 222 in 903fe64

wrapHaskell (showNameWithoutUniques n <> maybe "" (" :: " <>) ((prettyType <$> identType dets) <|> maybeKind))

124 chars:

haskell-language-server/ghcide/src/Development/IDE/Spans/AtPoint.hs

Line 318 in 903fe64

modToLocation m = fmap (\fs -> pure $ Location (fromNormalizedUri $ filePathToUri' fs) zeroRange) $ M.lookup m imports

[colonelpanic8]

Does not seem limited to that file though. Here are some more examples over 100 chars:

108:

haskell-language-server/plugins/hls-call-hierarchy-plugin/test/Main.hs

Line 414 in 903fe64

incomingCallMultiFileTestCase :: FilePath -> Int -> Int -> M.Map FilePath [((Int, Int), Range)] -> Assertion

104:

haskell-language-server/ghcide/src/Development/IDE/Core/Debouncer.hs

Line 42 in 903fe64

asyncRegisterEvent :: (Eq k, Hashable k) => Var (HashMap k (Async ())) -> Seconds -> k -> IO () -> IO ()

148:

haskell-language-server/ghcide/src/Development/IDE/Core/Compile.hs

Line 347 in 903fe64

session' = session { hsc_dflags = updOptLevel 0 $ (ms_hspp_opts summary') { outputFile = Just dot_o , hscTarget = target}}

113:

haskell-language-server/ghcide/src/Development/IDE/Core/Compile.hs

Line 478 in 903fe64

let fake_splice_binds = listToBag (map (mkVarBind unitDataConId) (spliceExpresions $ tmrTopLevelSplices tcm))

[Ailrun]

@IvanMalison Thank you for the finding. It looks like stylish-haskell indeed does not support those cases.

[colonelpanic8]

@IvanMalison Thank you for the finding. It looks like stylish-haskell indeed does not support those cases.

Huh really? Some of those lines look like they have very simple multi-line versions that I would expect it would support.

[Ailrun]

@IvanMalison Yeah, I expected so too, but I just tried those specific examples, and stylish-haskell indeed doesn't change those lines.

[colonelpanic8]

@IvanMalison Yeah, I expected so too, but I just tried those specific examples, and stylish-haskell indeed doesn't change those lines.

I'm not super familiar with stylish-haskell. Will it allow you to change them to be multi-line defintions without reverting the changes?

It seems like maybe some diligence on the part of contributors not to make huge lines like these may be needed in addition to stylish haskell.

[Ailrun]

@IvanMalison AFAIK, if stylish-haskell doesn't support some cases, it won't revert them back too. Thus, contributors can manually multi-line them to make it fit into 80-column limit (though this is definitely not ideal)