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:
- 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;
- 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.
- 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 Functionalityfor path in paths do -- the core does this bit for loader in loaders do loader(path, library, object)
Existing Functionalityfor loader in loaders do for path in paths do -- the loader does this bit loader(path, library, object)
.hc
Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list