Unpopularity of global variables - why?

Terry Judd terry.judd at unimelb.edu.au
Fri Oct 12 19:54:49 EDT 2012


Well, I often use a single global multidimensional array to store all my settings and data and It very rarely causes problems. You declare the variable in every script and you're away. Easy enough to supplement with script locals or custom properties when required and it has the advantage of allowing you to save all your data out/in in one fell swoop using arrayEncode/decode.

Terry...

On 13/10/2012, at 8:25 AM, "Peter Haworth" <pete at lcsql.com> wrote:

> What Mark said.  Plus I've spent many a happy hour debugging code that was
> supposed to refer to a global variable except that I forgot to declare it
> as such in my script so it was treated as a local variable (in the days
> before realising that Strict Compile Mode is a good thing to do).  That's
> my own stupidity of course but any time I find a way to protect myself from
> my own mistakes, I'll take it!
> 
> Pete
> lcSQL Software <http://www.lcsql.com>
> 
> 
> 
> On Fri, Oct 12, 2012 at 1:50 PM, Graham Samuel <livfoss at mac.com> wrote:
> 
>> The discussion about Strict Compile Mode brought in a lot of stuff about
>> globals, and I sense that many people think they're a bad thing - I am not
>> talking about trick ways of using them, just regular globals that allow one
>> to refer quantities (numbers, strings, anything really) across scripts
>> which are housed in different objects in the same program (set of stacks).
>> 
>> The thing is, I can't see the objection. Clearly any technique can become
>> sufficiently messy and obscure as to negate its own usefulness, but what's
>> wrong with the idea itself? If I want to maintain for example a status
>> across a whole program, if I don't use a global, I am going to have to use
>> a custom prop or a function to transmit that status across object
>> boundaries, and that means more typing with no more security, so why do it?
>> What's wrong with
>> 
>>   if gMy_Status is "open"...
>> 
>> compared to
>> 
>>   if fMy_Status() is "open"…
>> 
>> or
>> 
>>   get the cpMy_Status of stack "myStack"
>>   if it is "open"…
>> 
>> Again, since the 'constant' command doesn't have global status, what's
>> wrong with using globals to store program-wide constants? Is any other way
>> cleaner?
>> 
>> Obviously I'm missing the point - I know I am. It's probably my age. But
>> I'd like to see a more reasoned attack on globals before I give them up.
>> 
>> Graham
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