EmptyCrate Software. Travel. Stuff.

Chapter 5 of Real World Haskell covers the creation of our first Haskell module. The chapter seems to come prematurely from my perspective. I am not yet concerned about making a module while I'm still trying to understand the language.

One thing that did catch my attention is the Prelude.undefined special value which allows for easy creation of stub code:

-- This compiles but causes a runtime error if you try to execute it
text :: String -> Doc
text str = undefined

Bitwise Functions
We also learn in Chapter 5 that the bitwise manipulations we have come to take for granted in C, C++ and similar languages is now a library module. This is the first point at which I can see an obvious point where C++ would make more succinct and readable code than Haskell.

import Data.Bits
0x10000 `shiftR` 4 :: Int
7 .&. 2 :: Int

int i = 0x10000 >> 4;
int j = 7 & 2;

It seems clear to me that if your code consists of mainly bit manipulations, C++ or C might be the logical choice.