Joe Gottman wrote: > On the other hand, this being Perl, I do believe it should be easy to > specify the concurrent case. I think that a <forall> keyword (and a > <givenall> keyword corresponding to <given>) would be a good idea. > These would not be quite parallel to <for> and <given> because there > would be some subtle differences arising from the concurrent > processing. For instance, <forall> probably should not be used with > <last>, because <last> should stop subsequent iterations and the > subsequent iterations could already have occurred when it is called. > Similarly, <givenall> should not be used with <continue>, because the > next case might already have been checked when <continue> is called.
I don't think that there's need for a 'forall' keyword. Note that Perl 6 has both Lists and Bags, the difference being that a List is ordered while a Bag isn't. So what happens when you feed a Bag into a "for" statement? Conceptually, you'd expect to get evaluation across its members with no promises concerning the order of evaluation. Likewise, I wonder if there might be a more general way to handle the 'givenall' concept. Say, by marking a block as being concurrent (i.e., parallel) in nature rather than sequential (i.e., series). That is, you normally evaluate a block's statements in order from the first to the last; marking the block as concurrent would tell the parser that the order of evaluation within this block isn't important. If a block of "when" statements is parallelized in this manner, you get the effect of the proposed 'givenall' keyword without the inherent restrictions that requiring the keyword would impose. -- Jonathan "Dataweaver" Lang
