libdatabase : connection problem

[Dan Shafer]

Just goes to show you. I learn something every day about this language.

It would never have occurred to me to use an equal sign that way in  
Rev. I'm almost sorry I know that!

:-D

Dan

On Aug 28, 2005, at 8:46 PM, Trevor DeVore wrote:

> On Aug 28, 2005, at 6:12 PM, Dan Shafer wrote:
>
>>> Sunday, August 28, 2005 12:45:34 PM (GMT +02:00)
>>>
>>> event from button :
>>>
>>>   local tDbA = ""
>>>   local i = 0
>>>   local tDataA = ""
>>>
>>>
>> The above lines are doing nothing for you because they are  
>> incorrect syntax for Revolution. The expression "i = 0" evaluates  
>> to either true or valse but does nothing with the result. IF what  
>> you intend to do here is to initialize local variables, then you  
>> need the slightly more verbose:
>>
>> local tDbA
>> put empty into tDbA (or you can use double quotes instead of "empty")
>> local i
>> put 0 into i
>> local tDataA
>> put empty into tDataA
>>
>
> Dan,
>
> Declaring a variable as local initializes to an empty variable. So -
>
> local tDbA,tDataA
>
> would initialize both variables as empty.  For example:
>
> on doSomething
>     local tVar
>
>     put tVar &cr& tVar2
> end doSomething
>
> Would display and empty line, a return and "tVar2" on the second  
> line in the message box.  You can initialize a variable to value as  
> well.
>
> on doSomething
>     local i = 0
>
>     put i
> end doSomething
>
> would print 0 in the message box.
>
>
>> Having said that, it is strictly optional in Transcript to use the  
>> word "local" and I'd venture to say that the vast majority of us  
>> never use it. Variables are local unless they're explicitly  
>> defined to be global. In that case, you eliminate the three  
>> "local" lines in the above and just assign the initialization  
>> values to the variables with the same effect.
>>
>
> The person probably got the code from original libDatabase example  
> code.  Back in the day I used to initialize variables with ""  
> before I knew that just declaring them set them to empty.    Now I  
> just define all local variables en mass:
>
> local tVar1,tVar2
> local tDataA,tWhateverA
>
> For integers, such as i, I used to always initialize them to 0.   
> Now I only initialize them with 0 if there is a possibility of a  
> math error later on in the code that could be caused by having a  
> non-numeric value.
>
> It is true that most people don't declare local variables but I do  
> in all of my code.
>
>
> -- 
> Trevor DeVore
> Blue Mango Multimedia
> trevor at mangomultimedia.com
>
>
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