I'd suggest using some different kind of brackets to relieve the
misery, like {| |}.
On Wed, Apr 15, 2009 at 4:10 PM, Conor McBride
Hi folks
In search of displacement activity, I'm trying to tweak Language.Haskell.Exts to support a few more perfidious Exts I have in mind -- they only need a preprocessor, but I do need to work on parsed programs, ideally.
I was hoping to add a production to the grammar of types to admit expressions, delimited by braces:
{ exp }
The idea is that instead of writing, (er, hi Claus),
data True data False
one just re-uses yer actual Bool (which becomes kind {Bool}) and writes {True} or {False}.
The trouble is, the production I've added causes a reduce/reduce conflict in the grammar, but I don't get any more precise complaint than that.
I guess what I'd like to know is whether I just need to debug my grammar extension, or whether the notation I'm proposing actually introduces a serious ambiguity that I'm too dim to notice. I'm mostly sending this in the hope that I have one of those "d'oh" moments you sometimes get when you articulate a stupid question in public.
Put me out of my misery, please...
Cheers
Conor
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