What does 'shadows' mean?

Alex Tweedly alex at tweedly.net
Mon Oct 10 08:34:10 CDT 2011


Hmmm   - a bit of a long shot, but worth trying.

I recently discovered that even when 'explicit variables' is turned on, 
you don't always need to declare a variable !!  I thought this was a 
bug, and reported it, but the official reply was that this is intended 
behaviour. Seems wrong to me, but apparently that's the way it is.

If a variable is used as a repeat loop control variable (e.g. repeat for 
each key K in ...., etc.) then it is *implicitly* declared for you, and 
won't cause an error even if explicit variables is on. And then, if you 
subsequently do declare a variable with that name, then you get the 
"shadows another variable" error.

For example, (the entire script)
> on abc
>    repeat with t1 = 1 to 10
>       -- do nothing
>    end repeat
>    local t1
>    put "asd" into t1
> end abc
t1 is implicitly declared in line 2, and then line 5 produces an error. 
Turning off explicit variables fixes the error.

I'm not quite sure if that could cause your problem, but it's another 
thing to check for.

-- Alex.

On 10/10/2011 11:56, Alex Tweedly wrote:
> You're right - it does (normally) mean that the variable you are 
> trying to declare shares a name with a previously declared variable.
>
> No idea why you're getting it in this case.
>
> Poor ideas :
>   - If you like, send me the script and I'll look to see if it fails here
>   - try it in an earlier (or later) version of LC
>   - change every occurrence to 't2' and see what happens.
>
> -- Alex.
>




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