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Topic: Re: Name Spaces - or Lack Thereof...
Conf: (P-PDF) Developers, Msg: 57762
From: kt
Date: 5/29/2002 05:27 PM


> From: "Terrill"
>
> ----- AcroBuddies Forum | www.acrobuddies.com ------
>
> Here's a good one for ya! I've been programming in C since 1984, and this blew
> me away... sorry for the length, but I don't like leaving out details (it's
> the Assembler Language programmer in me):
>
> 1. Create two text fields. We'll call 'em "fa" and "fb"
>
> 2. In the "validate" tab for fa, click on the "Custom validate scrip," and
> edit the script.
>
> 3. Copy/Paste the following code:
>
> // ----CODE STARTS ----
>[snip]



One of the things your code illustrates is the danger of using uninitialized
variables.

For example, you declare 'x' without a value. Then, a few lines later,
you're using the '+=' operator on it. Not good coding practice.

The namespace issue is a legit one. The way it currently works is that local
variables are parented off of the Doc object. Hence, all local variables, in
all code blocks throughout the document, share a namespace. I believe it's
likely that this will change someday, but for now, that's how it is.

Nevertheless, it shouldn't matter if LOCAL variables collide with each other
in namespace, because local variables are used for transient, here-and-now
calculations involving transient values. The only possible way that the
namespace collision problem could pose a problem is if you are in the habit
of delcaring and using uninitialized variables. This is why you ran into the
problem in the first place.

The moral:

1. Locals are not and should not be used as globals. Hence, it is okay if
they share a global namespace.

2. The only way you can run into this kind of trouble is by using
uninitialized variables.

KT


-------------------------------------------
Kas Thomas
Read the AcroRage column every week at
http://www.acroforms.com/cgi-bin/rage.pl
-------------------------------------------







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