Re: [Haskell-cafe] history of tuples vs pairs

2008/6/25 Conal Elliott <conal@conal.net>:

I have a foggy memory that early ML had only binary pairing, nesting for n-tuples. Can anyone confirm this memory. If so, does anyone remember the rationale for going to n-tuples? Performance, perhaps?

Similarly, did the Haskell designers consider pairs as an alternative to n-ary tuples?

I think performance was part of it: accessing the nth element of a tuple is O(1), but the nth element of a nested pair is O(n). On the other hand, you can't internally represent nested pairs as n-tuples because of laziness. (a,(b,c)) has elements of the form (x,_|_) that don't correspond to any triple. -- Dave Menendez <dave@zednenem.com> <http://www.eyrie.org/~zednenem/>