[Guido]
I guess it's my anti-Scheme attitude. I just think the problem is in the deeply nested structures. There usually is a less nested data structure that doesn't have the problem.
A couple more thoughts: There's a difference between nested data structures and recursion. Use of one doesn't necessarily imply the other. Also, whether a given data structure is "nested" or not can depend on your point of view. Most people wouldn't consider a linked list to be nested -- it may be "wide", but it's not usually thought of as "deep". I don't think it's unreasonable to ask for a pickle that doesn't use up a recursion level for each unit of width in such a structure. Greg Ewing, Computer Science Dept, +--------------------------------------+ University of Canterbury, | A citizen of NewZealandCorp, a | Christchurch, New Zealand | wholly-owned subsidiary of USA Inc. | greg@cosc.canterbury.ac.nz +--------------------------------------+