* Luke Palmer
2009/1/3 Xie Hanjian
Hi,
I tried this in ghci:
Prelude> 1:2:[] == 1:2:[] True
Does this mean (:) return the same object on same input,
Also, in functional programming, *every* function returns the same output for the same input. That's part of the definition of function. :-)
This is true in Haskell, but may not true in Scheme (I guess also false in Lisp). In DrScheme:
(eq? (cons 1 2) (cons 1 2)) #f (equal? (cons 1 2) (cons 1 2)) #t
Although equal? treats the two as the *same*, they're different lists because if we modify one (e.g by set-car!) the other won't be affected. So here comes another question: when we say a function always give the same output for the same input, what the *same* means here? ídentity or equality? Thanks Jan
Luke
_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
-- jan=callcc{|jan|jan};jan.call(jan)