marlowsd at gmail.com
Thu Sep 20 11:27:05 CEST 2012
On 19/09/2012 20:01, Ian Lynagh wrote:
> On Wed, Sep 19, 2012 at 07:28:23AM +0000, Simon Peyton-Jones wrote:
>> | > Somehow compiling DynFlags.lhs has started taking a very long time, and
>> | generates lots of code. I have not had time to investigate, but if anyone has any
>> | idea what is happening I'd be happy to know.
>> | I've added some more stuff to it recently. In particular, a large type:
>> | includes/dist-derivedconstants/header/GHCConstantsHaskellType.hs
> It's mostly the Read instance, but partly the Show instance, of the
> type. I've attached a simple example with just a Read instance;
> compiling with
> ghc -O -c W2.hs
> takes a while.
Instead of using Read/Show, you could generate some code in
mkDerivedConstants to use ReadP and Outputable, which should be much
smaller and faster.
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