How to find out GHC's memory representations of data types?

Question

Recently, blog entries such as Computing the Size of a Hashmap explained how to reason about space complexities of commonly used container types. Now I\'m facing the questio

Answer 1

Memory footprints of Haskell Data Types

(The following applies to GHC, other compilers may use different storage conventions)

Rule of thumb: a constructor costs one word for a header, and one word for each field. Exception: a constructor with no fields (like Nothing or True) takes no space, because GHC creates a single instance of these constructors and shares it amongst all uses.

A word is 4 bytes on a 32-bit machine, and 8 bytes on a 64-bit machine.

So e.g.

data Uno = Uno a
data Due = Due a b

an Uno takes 2 words, and a Due takes 3.

Also I believe it is possible to write a haskell function which performs the same tasks as sizeof or offsetof