[PD] array size (was Re: arraysize)

Miller Puckette msp at ucsd.edu
Wed Oct 3 17:03:47 CEST 2012 

Problem is, it's a bug - I want to fix it :)

M

On Wed, Oct 03, 2012 at 11:44:47AM +0200, Cyrille Henry wrote:
> hello,
> 
> since externals can override internals, why not leaving hip~ untouched, and providing a corrected hip~ that is installed in pd/extra/0.44
> one can just remove path > 0.43 it pd preference (or even using start-up flag) to have the old hip~, or keeping path untouched to have latest version of pd objects.
> 
> cheers
> c
> 
> 
> Le 03/10/2012 02:33, Miller Puckette a écrit :
> >Right, the two demands I'm trying to reconcile are keeping the name
> >hip~ (so that old patches remain comprehensible) and yet making hip~
> >work correctly -- it's a bug fix.  Seems to me one ought to be able to fix
> >bugs without diving into library version confusion.
> >
> >I think namespaces are very useful to expert programmers but are likely to
> >be confusing to many Pd users -- and its not that much of a necessity if
> >indeed c (in which Pd and linux are implemented) didn't need to have
> >them.
> >
> >cheers
> >Miller
> >
> >On Tue, Oct 02, 2012 at 08:24:19PM -0400, Hans-Christoph Steiner wrote:
> >>
> >>If you think that's the preferrable approach, then shouldn't it be
> >>[newhip~]?  One thing libc did not do is break backwards compatibility
> >>of functions.  I think the libc example is a better approach than the
> >>-pre-0.44-hip flag or the aliasing to work around the existing versions
> >>of [pow].
> >>
> >>My central point is that Pd should have a fully functioning namespace
> >>like modern languages do (C++, Obj-C, Java, Python, Ruby, Lua, Haskell,
> >>etc. etc.)  That's one lesson that we've learned from C.  Part of that
> >>is having a standard library that can be overridden.  Then if people
> >>want to have old versions of the standard library, they can easily be
> >>accomodated by adding the version number to the name of the library.
> >>
> >>.hc
> >>
> >>On 10/02/2012 07:02 PM, Miller Puckette wrote:
> >>>The libc way is just to have one libc and kludge your way through
> >>>compatibility problems.  For instance, seek() had to be replaced with lseek(),
> >>>gets and fgets were left with not-quite-the-same behavior, errno was
> >>>magically adapted to become a macro that grabbed a thread variable when
> >>>threads appeared, etc.  It's not pretty but way preferable to having
> >>>several versions of libc - what a nightmare that would have been.
> >>>
> >>>cheers
> >>>Miller
> >>>
> >>>On Tue, Oct 02, 2012 at 06:48:46PM -0400, Hans-Christoph Steiner wrote:
> >>>>Is the static variable you are talking about the "static t_class"
> >>>>declaration in the class C files?
> >>>>
> >>>>What's the libc way?
> >>>>
> >>>>The -pre-0.44-hip way would be easy to implement, but it has a number of
> >>>>problems:
> >>>>
> >>>>- there will be many flags like this, -pre-0.42-pow, etc. etc.
> >>>>
> >>>>- there will be no way to specify in the patch that it should use a
> >>>>specific version of hip~, pow~, etc.  That adds complexity to the patch
> >>>>setups since each patch will need an accompanying script for launching
> >>>>Pd properly and means Pd programmers have to learn non-Pd things like
> >>>>scripting to do this.
> >>>>
> >>>>.hc
> >>>>
> >>>>On 10/02/2012 06:39 PM, Miller Puckette wrote:
> >>>>>Actually I think my previous post was wrong - what I was unable to do was
> >>>>>get different sets of static variables for dlopen() - ing the _same file
> >>>>>twice_ -- which isn't what we're talking about here.
> >>>>>
> >>>>>But still, I think the libc way is much simpler and likely to be much more
> >>>>>robust.
> >>>>>
> >>>>>cheers
> >>>>>M
> >>>>>
> >>>>>On Tue, Oct 02, 2012 at 06:13:32PM -0400, Hans-Christoph Steiner wrote:
> >>>>>>Since Pd manually loads the libraries (.pd_linux), it can also manually
> >>>>>>map a given function address to the s_thing in the symbol table.  There
> >>>>>>is no need to load the symbols in a .pd_linux in the sense of a public
> >>>>>>shared library, and therefore no nameclashes.  Pd could get the address
> >>>>>>of the new() function using dlsym() and store that wherever.  This is
> >>>>>>already happening for the setup() function, so we can do the same thing
> >>>>>>to map the new() function to a symbol..
> >>>>>>
> >>>>>>So for example, pd could map the new() function to the fully qualified
> >>>>>>name in the symbol table, i.e "vanilla-0.42.5/hip~", then only in the
> >>>>>>canvas_local namespace would the symbol "hip~" be mapped to the new()
> >>>>>>function.
> >>>>>>
> >>>>>>.hc
> >>>>>>
> >>>>>>On 10/02/2012 05:09 PM, Miller Puckette wrote:
> >>>>>>>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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> >>>>>>>>_______________________________________________
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> >>
> >
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