Script local variables

[Earthednet-wp]

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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