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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