GIML: Tutorial Six: More Hints

fun sort (f:'a -> real) nil = nil
|   sort f (h::t) = let
  fun insert x nil    = [x]
  |   insert x (h::t) = if f x > f h then x::h::t else
					  h::insert x t
in insert h (sort f t) end;

This particular version of sort allows us to specify the quantity to sort on. The quantity must be a real number - for example population or GDP.

Enter the following lines in sequence

sort area europe;
hd it;
name it;

A list of countries with the largest (in area) first.
The first country in the list.
The name of the first country in the list

All this might be done in one go as follows:

val bigArea = name(hd(sort area europe));