Re: [Haskell-cafe] Re: Is 78 characters still a good option? Was: breaking too long lines

On Fri, Apr 24, 2009 at 9:07 AM, Achim Schneider wrote:

Xiao-Yong Jin wrote:

...

Gwern Branwen writes:

...

I was cabalizing a package once, and I chucked into the build-depends 'ghc' and made it build. About 30 seconds later, it occurred to me that this was a geometry library and what the heck was it doing with the GHC API? So I go looking, and I find a module of utility functions. It's importing GHC.Base. I remove the import and scroll down to see the error.

It turns out that 20 megabytes of GHC code was being linked into this program for one function. I took the quick way out and typed into the module: 'isJust Nothing = False; isJust (Just a) = True'.

Probably I'm missing something, but why didn't you just import Data.Maybe?  I believe both 'isJust' and 'isNothing' is defined in the module.

...and that's TRWTF.

I'm fairly sure that what I did after copying in the function was switch to an import; my ultimate fix was easy and irrelevant. This was a long time ago, and what made it stand out in my mind was my horror at discovering for a trivial 2-liner, all of GHC was being depended upon. -- gwern