[PD] array size (was Re: arraysize)

Miller Puckette msp at ucsd.edu
Tue Oct 2 23:09:08 CEST 2012


I'm not sure that any of the Windows, MaacOS, and linux dynamic loading
systems will support having multiple versions of a library loaded in the
same address space.  But here's a simpler way anyhow:  libraries such as
vanilla could maintain compatibility by querying the version number of
the patch at run time.

In the case of hip~  I'm genuinely not sure whether the "correct" behavior
would then be to revert to the old behavior for all old patches or only on
request.  The confusing scenario I worry about is that you have a patch with 
an old hip~ object in it, save it from 0.44, and then have it switch to the
new behavior next time it's loaded.

I think I have found ad hoc ways to fix the other problems without breaking 
old patches.

cheers
Miller

 n Tue, Oct 02, 2012 at 11:36:47AM -0400, Hans-Christoph Steiner wrote:
> 
> I think having a compatibility version stamp in the patch is a good
> idea.  This ties in well with the experiments I've been doing with
> splitting out all of the objects from pd itself.  If all of the core
> objects are a standard library, then that means its easy to choose which
> version of the standard library that a patch is using.  In Pd-extended,
> this is called the 'vanilla' lib, and its been included in some form
> since 0.42.
> 
> Then if a patch has a compatibility version stamp in it, Pd can
> automatically look to see if it has a copy of that version of the
> standard library, and load it.  Otherwise, it would load the version
> closest to that, and throw a warning, or optionally that could be
> considered an error.
> 
> To make this work well, the key missing feature is the ability to change
> which loaded library an object name maps to in the canvas-local
> namespace.  Currently, once an object name is mapped to a loaded
> .pd_linux, that is a global association.  This is needed so that patches
> using different standard libs can be open at the same time.
> 
> Then making the versioned standard libs would be pretty easy, mostly
> just bundling the right .c files into a lib.
> 
> .hc
> 
> 
> On 10/02/2012 11:15 AM, Miller Puckette wrote:
> > This is in my long-range plan but hasn't yet risen to the level of "urgent".
> > However, this migth be a good moment to get started on this because several
> > other backward- and even forward-imcompatible needs are also rising to the
> > fore:
> >
> > 1. there's a bug in hip~ - its DC gain is slightly (and possibly considerably)
> > greater than 1.  "fixing" this will change the audio output of older patches,
> > usually much too slightly to matter, but there will have to b a "-pre-0.44-hip"
> > flag or something to allow strict back compatibility;
> >
> > 2. There's no place in the pre-0.43 file format to alow specifying individual
> > box widths and font sizes; I put an "f" (=format) message to the canvas
> > object in 0.43 so that in 0.44 I can make it set font size and box width and
> > perhaps leave an opening for other formatting info.
> >
> > 3. the upsampling inlet~ by default zero-pads its input.  This is incorrect as
> > its DC gain is less than one.  (Try using that as input to a phasor~ for
> > instance - bad surprise!)  I want to change the default so that it acts like
> > a sample-and-hold, which I believe is an option now.  To preserve back 
> > compatibility I'd keep all the "upsampling methods" in place but only change
> > default behavior for patches with a 0.44 or later version stamped on them.
> >
> > Each of these presents a different spin on the age-old issue of keeping
> > total back compatibility in place, even when the compatibility is to preserve
> > a big as in (1) and (3) - and arguably in the file searching too; I'm not sure
> > whether to regard that as a bug or just over-hasty design.
> >
> > cheers
> > Miller
> >
> >>
> >>       Here's a good sketch of the idea
> >>       (http://puredata.info/dev/PdSearchPath):
> >>
> >>
> >>       Proposed Functionality
> >>
> >>    for path in paths do -- the core does this bit
> >>      for loader in loaders do
> >>        loader(path, library, object)
> >>
> >>
> >>       Existing Functionality
> >>
> >>   for loader in loaders do
> >>     for path in paths do -- the loader does this bit
> >>       loader(path, library, object)
> >>
> >> .hc 
> >>
> >>
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