FAQ: How to Use Extensible Records in GHCi

S. Alexander Jacobson haskell at alexjacobson.com
Mon Mar 29 18:14:10 EST 2004

I feel like I have way too much code of the form:

   changeGpart (C a b c d e f g h i) g' =
	C a b c d e f g' h i

So, I got excited reading Simon and Mark's
"Lightweight Extensible Records For Haskell" paper
as a way to get rid of this cruft.  I immediately
started GHCi, typed {a="Hello world"}, and got an

Is the feature described in the paper just a
proposal or is there a switch somethere to enable

Alternatively, perhaps this code is a common
beginner mistake due to ignorance of the proper


S. Alexander Jacobson                  mailto:me at alexjacobson.com
tel:917-770-6565                       http://alexjacobson.com

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