Collecting all external names in a module
johan.tibell at gmail.com
Mon Sep 20 16:06:38 EDT 2010
On Mon, Sep 20, 2010 at 12:47 PM, Simon Peyton-Jones
<simonpj at microsoft.com>wrote:
> Thomas had it right; it’s just a particular kind of fold. The key
> parts of the traversal would be:
> · Occurrences. getExpr g (HsVar v) = g_occ g v
Don't I need to work on LHsExpr rather than HsExpr? How would I otherwise
get the location?
getExpr :: Gather v res -> LHsExpr v -> res
getExpr g (L loc e) = case e of
HsVar v -> g_occ g (L loc v)
HsApp e1 e2 -> g_union g (getExpr g e1) (getExpr g e2)
> · Binding> getExpr (Lam v e) = g_del v (getExpr g e)
I still don't quite the purpose of this, is it to say the v is now shadowing
whatever had the same name in the scope surrounding the lambda? Or is
"g_del" intended to mean "g_declaration" and capture the declaration sites
(and if so, how I know if it's a exported top-level declaration or not)?
> Does that help? Maybe one could generalise a bit.
Definitely. Thanks for the pointers.
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