Show-like output of GHC data types

Nicolas Frisby nicolas.frisby at
Fri Mar 8 17:26:06 CET 2013

On Fri, Mar 8, 2013 at 9:39 AM, Simon Peyton-Jones <simonpj at>wrote:

>  What I would like to see is something like:****
> HsApp (HsApp (HsApp (HsVar "foldl'") (HsVar "+")) (HsLit 0)) (HsVar "xs")*
> ***
> We could derive ‘Show’ on everything but that would generate a LOT of new
> code, that would seldom be used.  Also ‘Show’ doesn’t pretty-print so the
> result would be illegible. ****
> **
If plugins could be used before the conversion to Core, such a plugin might
be a tidy way to workaround the issue of bloating GHC's binary size with
all that Show code.

This previous email thread
relevant, and Marlow's comment there makes it sound like a pretty easy
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