[PD-dev] list object operators

[Frank Barknecht]

Hallo,
Thomas Grill hat gesagt: // Thomas Grill wrote:

> in my patches i often need mathematical manipulation of lists of 
> floats, which is not very convenient with internal objects.
> What about adding new verbs to the list objects, including often used 
> mathematical operations?
> I would be thankful for + - * / in the beginning, but of course all 
> kinds of unary and binary operations would be handy.
> Sure i know of Franks abstractions, but speed is an issue.

I agree with you here. With the [list]-abs I also want to offer a
suggestion, how these objects could look like. I intended to loosly
follow the standard set by the builtin list objects and of course they
should work with plain Pd as well. 

However as they are abstractions, their internals can be replaced by
(external) objects tuned for speed without having to change any of the
patches, that use the [list]-abs-abstractions, because the "API"
stayed the same.  I'm about to create a version of [list]-abs that
does just this: [list-drip] with using [drip] internally etc. With
some "-path"-trickery this can be used as needed, if the used
externals are available, or not, if using plain Pd is necessary (like
in some workshops or on PDa).

Regarding your suggestion of speeding up list-math: What about
extending [expr] to handle lists as well? Maybe a new variable could
deal with this like $l1, $l2, ..., so that things like this would be
possible: [expr $f1 * $l1]. 

I didn't think too much about the best syntax for list-expr yet, like
when should the result be a list, when should it be a scalar, how to
handle the two kinds of multiplication possible with [expr $l1 * $l2]
(inner product with a scalar result vs. element-wise product to a
list), what to do with "mixed" lists that also include symbols and
gpointers etc., but the basic concept looks very useful to me.

Besides that, a [list drip|serialize] and negative indices for [list
split] - see my patch in the SF tracker - would be *very* handy.

Ciao
-- 
 Frank Barknecht                 _ ______footils.org_ __goto10.org__