Hi Uri, Not sure if it was because I've been dealing with mainly web servers for the past few years, but I always read your name as U-R-I instead of Uri. :-) It looks like you've got a name that's relevant to your profession, most of us didn't have that fortune!
On Thursday 13 May 2010, Uri Guttman wrote: > > there are two ways to declare (not define) a hash at a file scope (which > is what you are calling main part). my declares it lexically to the file > which is decent if needed. our declares it as a package global which > means it can be accessed from any code using the fully qualified name or > it can be exported too. both have their uses. but using globals in > general is not a good idea if you can avoid it. the issues are well know > and include action at a distance (some other code can modify your hash > and you won't know why/where/what about it). passing data is safer > because it isolates the data to the code that needs it. > > isolation is a major coding philosophy all coders need to > learn. isolated code means you can test more easily (no side effects or > outside code to worry about). you can replace isolated code easily as it > isn't intertwined with other code and data. > Your explanation is much appreciated. So in general, we should make the variables as least visible as we can. In that case, I don't think we should cover much code at the file scope. The code at the file scope should be moved to a lexical scope through a subroutine for more elegance. Correct? > APK> 3) Also, am I correct in guessing that the memory that's used to > APK> allocate a variable defined with 'my' will be freed up once the > APK> current lexical scope is exited? > > true but with a file lexical (or global) that won't happen until the > program exits. this is another reason to declare things in the tightest > scope possible. also note that the memory is freed up for perl to reuse, > not for the OS. it will mean perl won't need to grow its size if it can > reuse lexical data that is reclaimed upon scope exit. > Doesn't Perl free up any memory that was used by it until the program exits? If that's how it goes, if a Perl program uses a lot of memory at the beginning and it takes lots of time for the program to finish up, all those memory space are being wasted, no? -- Regards, Akhthar Parvez K http://Tips.SysAdminGUIDE.COM UNIX is basically a simple operating system, but you have to be a genius to understand the simplicity - Dennie Richie -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
