>>>>> "JDP" == John Douglas Porter <[EMAIL PROTECTED]> writes:
JDP> Uri wrote: >> isa >> is a key valid? (not same as in a set). >> isa usually works on fixed sets of keys JDP> Well, in a strict sense it IS the same, as it is just one JDP> of many possible set operations. I suppose you could say JDP> it's a subset of sets. :-) I think you're trying to focus JDP> on the difference between sets of strings, which are the JDP> hash keys() directly, and sets of other things (e.g. objects), JDP> which are hash values(). You also emphasize the const-ness JDP> of the "isa" key set, which I think is rather too narrow. JDP> I think a better approach would be to talk about sets in JDP> general, the many set operations (including the *missing* JDP> operations, which have to be kludged in Perl), the set- JDP> related CPAN modules, and how all these things can be used. JDP> JMHO. Sorry if someone already made this point and I missed JDP> it. i do plan on covering sets in their own right along with intersection and union operations too (right out of the FAQ). but i still think isa is a (sic) concept that is important enough to cover on its own. sure it is a set but a very specific type with its own name. the names of these concepts are important (almost like design patterns which i despise :). i have seen too many newbies and even some mildly experienced perl hackers don't know all these hash uses (or their names). ever see the (virtual) glassy eyes when you mention dispatch tables in polite public? :) i am aiming this for my class which is a mix of experienced hackers down to some ex-cobol coders who code perl because they get paid for it. and it is also for future classes or writings. so i want to cover as many uses at a basic level and not get into subtleties such as which are really variations of each other. they are all hash variations when you come down to that so the context and name of each use must be clearly explained. i will post here the url for these slides (with mistakes! :) when i get them done. please be kind. :) thanx, uri -- Uri Guttman ------ [EMAIL PROTECTED] -------- http://www.stemsystems.com --Perl Consulting, Stem Development, Systems Architecture, Design and Coding- Search or Offer Perl Jobs ---------------------------- http://jobs.perl.org
