Bug or just something you can't do ?

[Peter Haworth]

Hi Alex,
I entered bug# 10070 about this back in March.  Trevor DeVore added a
comment that it was a duplicate of bug#  which dates back to July 2008.
 Any bets on whether this will ever be fixed?

Pete
lcSQL Software <http://www.lcsql.com>



On Sun, Sep 30, 2012 at 4:31 PM, Alex Tweedly <alex at tweedly.net> wrote:

> On 01/10/2012 00:15, Richard Gaskin wrote:
>
>>
>> I would have expected it, but I can see value in allowing what you
>> suggest.  I'm just not sure how to go about it.
>>
>> Args are evaluated before being passed in, so:
>>
>>    increment tA[1]
>>
>> ...becomes:
>>
>>    increment (the value of element "1" in the array tA)
>>
>>  ?
> So doesn't
>    increment t
> become
>   increment (the value of t)
>
> ?
>
> If you look closely at the simple case
>
>> command increment @p
>>    add 1 to p
>> end increment
>>
>> on mouseUp
>>    local t, tA
>>    put 2 into t
>>    increment t
>>    put t &CR after msg
>>
> you see that *because the parameter specifies 'pass-by-ref',* a reference
> to the container is passed, without evaluating the actual parameter. So
> what I woudl expect (or at least, wht I want :-) is for
>    increment tA[1]
> to be evaluated as far as
>    increment (the reference to the container tA[1])
>
>  One option for passing the array would be to pass the whole thing with a
>> specifier for the element to be affected as a separate argument:
>>
>>   increment tA, 1
>>
>> But you've probably already considered that.
>>
>>  Yeah. My problem is that I have a whole set of functions that take in an
> array, passed by ref, and update that array; I've now realized that *in
> some cases* the calling handlers don't need just one (or two) array(s) -
> they need to handle a large number of arrays. So I changed all the code
> from something like
>
>    ("read the data into gArray")
>    put myFn(gArray) into tResult
>
> into something like
>    repeat for each dataset D
>       read data into gArray[D]
>       put myFn(gArray[D]) into wherever
>    end repeat
>
> But of course, in other places, I still only have a single array to deal
> with.
>
> For now I've inserted the ugly construct
>
>    repeat for each dataset D
>       read data into gArray[D]
>       put gArray[D] into temparray
>       put myFn(temparray) into wherever
>       put temparray into Array[D]
> end repeat
>
> (ick !! - but it works)
>
>  So we have a question:  if enough folks find this sort of suggested
>> syntax useful, by what syntactic means could we tell the interpreter not to
>> evaluate the argument?
>>
>
> There's no need for any syntactic means - the use of "by-ref" in the
> handler specification is already there, and is already used to
> differentiate how to pass it in the "simple case" (unless I'm missing
> something).
>
> -- Alex.
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