Script local variables

[André Bisseret]

Bonjour,

From liveCode Dictionnary:
"The value of a local variable is retained only while the handler is running. When the handler exits, the value of the local variable is lost.

The value of a script local variable is retained between handlers,"

For more information have a look at "local" in the dictionnary

Best regards

André


Le 22 févr. 2014 à 17:04, Earthednet-wp a écrit :

> Mats' posting on encryption difficulties got me thinking about local variables. Are they supposed to persist after the script is done executing, so that the next time a handler within that script is called, they can be expected to hold previously set values? I notice that they don't. Or would this be a task for custom properties?
> Bill
> 
> William Prothero
> http://es.earthednet.org
> 
>> On Feb 22, 2014, at 2:54 AM, Peter W A Wood <peterwawood at gmail.com> wrote:
>> 
>> Many thanks to Roger Eller, Jan Schenkel, Bill Vlahos and Paul Hibbert (off list) for helping me identify and workaround the issues I encountered.
>> 
>> Paul pointed out three things: I didn't the use "the text of Field ..."; how to overcome not being able to copy text from a field in an OS X standalone; and the final problem that was related to script local variables.
>> 
>> Using "the text of Field ..." instead of "Field ..." helped to more accurately copy and paste data. (I ended up displaying the encrypted data in Hex anyway.) 
>> 
>> I had found that I couldn't copy from a Field in an OS X standalone. Paul provide a script with group handlers to get around the problem. I have submitted a bug report which has been accepted - http://quality.runrev.com/show_bug.cgi?id=11830
>> 
>> At this stage, I was still getting inconsistent results when encrypting data in the IDE or a standalone. Then Paul noticed how I was initialising the encryption parameters, namely the script local variables tPassword, tSalt, tIV:
>> 
>>   openStack
>>         put "" into Field "Encrypted"
>>         put "12345678123456781234567812345678" into tPassword
>>         put "12345678123456781234567812345678" into tSalt
>>         put "12345678123456781234567812345678" into tIV
>>   end openStack
>> 
>>   on encryptMSG
>>         ...
>>   end encryptMSG
>> 
>>   on decryptMSG
>>         ...
>>   end decryptMSG
>> 
>> He changed this to re-setting the three script local fields each time they were used:
>> 
>>   on openStack
>>         put "" into Field "Encrypted"
>>   end openStack
>> 
>>   command setPassCodes
>>         put "12345678123456781234567812345678" into tPassword
>>         put "12345678123456781234567812345678" into tSalt
>>         put "12345678123456781234567812345678" into tIV
>>   end setPassCodes
>> 
>>   on encryptMSG
>>         setPassCodes
>>         ...
>>   end encryptMSG
>> 
>>   on decryptMSG
>>         setPassCodes
>>         ...
>>   end decryptMSG
>> 
>> After making this change, I now get identical results when encrypting data with the stack in the IDE or as a standalone.
>> 
>> I have also entered a bug report for this - http://quality.runrev.com/show_bug.cgi?id=11832 - I feel there is a bug but not in the encrypt/decrypt functions, it's in the handling of script local variables.
>> 
>> Once again, thanks for all the help.
>> 
>> Kind regards
>> Peter
>> http://LiveCode1001.blogspot.com
>> 
>> 
>> 
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