[Haskell-cafe] Re: Not to load Prelude

Henning Thielemann lemming at henning-thielemann.de
Fri Jan 11 17:36:14 EST 2008

On Fri, 11 Jan 2008, Luke Palmer wrote:

> So, when you write the number 3 in Haskell, GHC converts this to
> essentially (Prelude.fromInteger (3::Integer)) in its internal format.
>  So it doesn't matter if you import Prelude (), Prelude's version of
> fromInteger still gets called.  If you give -fno-implicit-prelude,
> then this is converted to simply (fromInteger (3::Integer)), without
> the hard-coded prelude reference.  That means you could write your own
> version of fromInteger that does something different.  A common usage
> for -fno-implicit-prelude (insofar as it is used at all, which is
> seldom) is to replace the standard Num hierarchy with a saner one,
> with numeric literals resolving to that one instead.
> There are a few other hard-coded references to Prelude in the internal
> format, but I don't remember what they are offhand.
> -fno-implicit-prelude gets rid of those, too.

For details, see:

I have summarized the answers so far:

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