[darcs-users] ratification (haskell_policy / hlint)

Neil Mitchell ndmitchell at gmail.com
Sun Sep 6 20:24:37 UTC 2009

Hi Jason,

>> I'd like this to be settled by consensus if possible.  But you know
>> where I stand if this keeps dragging out.
> I agree that explicit-per-use ratification is my preferred approach
> here.  I agree almost completely on the grounds of transparency.

In my generalised opinion explicit-per-use is the best approach for
safety - of course, I'm not hacking on darcs so your consensus
shouldn't include my opinion :-)

> Neil:  Is it possible for hlint to read comments?  As a random example:
> do c <- hGetContents h {-# HLINT: ignore "This use is safe." #-}
>   return c

GHC is sensitive about pragmas, but I'm sure I can come up with
something. I've thought about this before, and I think HLint probably
should have something. Any ideas? The issues are:

* Syntax - we need to choose something haskell-src-exts is happy
parsing and reading easily, but GHC doesn't choke/warn on.
* Scoping - my guess would be provide one way to turn it on/off, and
one method to apply the changes to the next declaration, and only put
hlint rules at declaration level.
* Features - we could have on/off control, or ability to add ignore
rules like are currently supported.

> Perhaps, it should work more like haddock where you use | and ^ to
> effectively point forward or backwards in the source at the usage.  I
> like the idea of being able to have a "comment" inside the ignore
> directive.

Yes, I think making sure there is a way to comment (and perhaps have a
flag to display all comments hlint encounters) is a sensible idea.

So in summary - great idea, if darcs decides that's the way to go,
I'll definitely implement it.

Sorry for the delay in replying, I've been at ICFP the last week.



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