Re: Typechecker plugins: request for review and another workflow question

I've just pushed wip/tc-plugins-amg, in which I remove the hs-boot file and unify the core2core and typechecker plugins under a single -fplugin flag. This did involve making a separate module for plugins, which I think is probably a good thing. I looked at using a hook instead, with a plugin to modify hooks, but I'm not sure exactly where such a plugin should be invoked. Ideally we want the typechecker modifications to work on a per-module basis, but most of the hooks seem to have a wider scope than that. Adam On 11/11/14 03:08, Eric Seidel wrote:

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On Nov 10, 2014, at 07:58, Austin Seipp wrote:

Hi Iavor;

I took a very, very cursory glance. Naturally I am not a typechecker guru, but I did look over the mechanical changes/extensions to thread things around. Two things popped out to me:

- 1) Ugh, a new .hs-boot file. I assume this wasn't added without good reason, but ideally we would be eliminating them quicker than we add them. :) I want to take a closer look at this; perhaps we can refactor something for you to remove the need for this.

- 2) I am kind of not a fan of having separate 'plugins for core2core' and 'plugins for typechecking' flags, AKA -ftc-plugin and -fplugin. Ideally I would think all plugins could be uniformly specified by simply saying '-fplugin'. This mostly avoids the need for duplication and a naming convention/slew of flags for each case (which we have to catalog and document). There may be an easy way to make this the case; I haven't looked closely yet (it has been some time since I starred at the plugin code, even though Max wrote it and I helped get it merged!)

I looked into this again a bit today and recall now why we made a separate Plugin type and flag; adding the TcPlugin to the existing Plugin type defined in CoreMonad creates a circular dependency between CoreMonad and TcRnTypes.

We could (and perhaps should) move all of the plugin types into a separate module, but that would require pulling other types (e.g. CoreToDo) out of CoreMonad to break the circularity.

-- Adam Gundry, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/