Negative doubles or floats in Haskell (macports)

Question

Why do I get a segmentation fault when I try to show a negative double or float? There is no problem for negative integers.

Prelude> let a = 4
Prelude> :t a
a :: Integer
Prelude> let b = -4
Prelude> b
-4
Prelude> :t b
b :: Integer
Prelude> let c = 5.6
Prelude> :t c
c :: Double
Prelude> let d = -5.6
Prelude> :t d
d :: Double
Prelude> show d
"-Segmentation fault

I tried it various ways, it seems that the number is correctly understood but not shown. Version info:

ghci --version
The Glorious Glasgow Haskell Compilation System, version 6.10.4

Answer 1

GHC on MacPorts seems to be broken. See https://trac.macports.org/ticket/25265

Consider instead installing the Haskell Platform from haskell.org, which includes GHC 6.12.3 and a bundle of Haskelly goodies.

• Info: http://hackage.haskell.org/platform/
• Link: http://hackage.haskell.org/platform/mac.html