[PD] what distinguishes a numeric symbol as an argument?
Matteo Sisti Sette
matteo.sistisette at email.it
Thu May 31 16:58:25 CEST 2007
Hi list
I understand that [symbol 43( is not the same as [43( as it is interpreted
as a symbol, not a float.
So I can send the message [symbol 43( to a symbol atom, or to any object
that works with symbols, and it will be handled just as if it was [symbol
dog(, right?
However, when this symbol is inserted as an argument into a message, or
packed into a list, what is it that distinguishes it from the number 43??
Let's make a practical example.
I want to dynamically set the label of a canvas so that it shows a number.
Suppose the receive symbol of the canvas is mycanvas_receive.
(1) The following doesn't work:
[label 43( (*)
|
[s mycanvas_receive]
(2) Nor does this:
[43( (or replace this with a number box)
|
[label $1( (*)
|
[s mycanvas_receive]
(3) Nor this:
[symbol 43(
|
[label $1( (*)
|
[s mycanvas_receive]
(4) While this DOES work
[43( (or replace this with a number box)
|
[makesymbol %d]
|
[label $1( (*)
|
[s mycanvas_receive]
However, I can't see any difference between the output of the message box
(*) in (4) and in (1-3).
If I connect that message box to a [print] in any of the four examples
above, the output is always "label 43".
It seems that the message that is generated in example 4 is intrinsically
but invisibly different from the previous 3 examples.
I may deduce that each argument of a message has an associated type that
somewhat depends on its "history" and cannot always be "seen"... which I
don't like but may be an explanation.
However, this does not explain the following:
* Isn't the output of [makefilename] in example (4) just the same as [symbol
43( of example 3?? Then why doesn't example 3 work as well???
Also, consider this:
(5)
[label 43(
|
[unpack s f]
and this
(6)
[symbol 43(
|
[label $1( (**)
|
[unpack s f]
In example (5), the second outlet of unpack outputs float 43, which is
(somewhat) coherent with the fact that example (1) didn't succeed to set the
canvas label
However, in example (6) unpack gives the error "unpack: type mismatch"... so
I guess that the "$1" (i.e. the "43") in (**) is seen as a symbol, not a
float....... but then, again: why didn't example (3) set the canvas label???
Anybody can help me to understand the underlying logic?
Oh shit!!!!!!!
Now I see that the following:
[symbol 43(
|
[print]
just outputs "symbol "
while
[43(
|
[makesymbol %d]
|
[print]
outputs "symbol 43" as expected....
isn't it weird??????
Well... again, if anyone can help me to undertsand this, I'll be grateful
Thank you
m.
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