Python is DOOMED! Again!

[Rustom Mody]

On Monday, February 2, 2015 at 1:13:30 PM UTC+5:30, Paul Rubin wrote:
> Steven D'Aprano writes:
> > No apples and no oranges aren't the same thing, but if somebody is expecting 
> > no apples, and I give them no oranges instead, it would be churlish for them 
> > to complain that none of them are the wrong kind of fruit.
> 
> https://davedevine.wordpress.com/2011/01/20/the-sartre-joke/

Actually the Sartre joke is more applicable to haskell than it might appear at first blush.

li = [1,2,3] : [Int] -- a monomorphic type
just as
lc = ['a','b','c'] : [Char]
lli = [[1,2],[3]] : [[Int]]

However [] is a polymorphic value ie
[] : [t]   -- t is a type variable

And now if we take
tail (tail (tail li)) 
you get []
just as if you take
tail (tail lli)

However the two '[]-s' are of different types
and so if you try to say append them you will get a Sartre error:

The list of no integers is incompatible with the list of no lists of integers