At 9:30 AM -0600 12/7/01, Bryan Hayes (Hayes Technologies) wrote:
I am totally new to Haskell, so maybe this is a stupid question. Various languages have pointers (or references), for good reason. Haskell can at least partly do without them (they are only existing internally somehow). My question is: Does Haskell principally not need pointers (i.e. in case of 2 data structures needing to reference an other very large data structure) or is this a design flaw or have a overlooked something?
In Haskell, you can arrange for a large data structure to be shared by giving it a name, and then using the name wherever you'd use a pointer in some other language. For example, in
t = [0..] -- could be quite large
b = 3 : t
c = 5 : t
the lists b and c share list t. Of course, these lists' implementations are full of pointers, but there's never a need for them to appear explicitly in Haskell programs. ------------------------------------------------------------------ Hamilton Richards, PhD Department of Computer Sciences Senior Lecturer Mail Code C0500 512-471-9525 The University of Texas at Austin Taylor Hall 5.138 Austin, Texas 78712-1188 ham@cs.utexas.edu hrichrds@swbell.net ------------------------------------------------------------------