Re: Call by reference vs. call by value

[dewar@cs.nyu.edu (Robert Dewar)]

Bob Duff said

"P.S. In thinking about this issue, one point is that for remote
procedure calls, you pretty much *have* to pass by copy, even for very
large things.  So a rule saying "all arrays are passed by reference" or
"all arrays that are not statically known to be small are passed by
reference (for some definition of small)" would break the Distributed
Systems Annex."

If you want to think more about this issue, worry about packed arrays
too. Requiring call by reference would mean that ALL packed arrays have
to be passed using general bit pointers, which would be unacceptably
inefficient in the normal case where slices are not passed. Same
thing for records, all records would have to be passed by bit address,
just in case the record you are passing is a field in a rcord with a
record rep clause.

This is not an easy problem to solve -- if there were a simple solution,
I think it might have been found by now, but there doesn't seem to be one.