Robert, it was you who suggested to use it if I remember correctly. How would it be different from what you just proposed?
Marco On Thu, Apr 29, 2021 at 8:07 PM Robert Goldman <rpgold...@sift.info> wrote: > That slot *is* there, but it is specifically noted as being for ASDF 2 > compatibility only, and not to be used. So you are using this at your own > risk. > > Having a :plist slot might be a good addition, as well (i.e., both of my > 2 proposed solutions) as something lighter weight than my second > alternative which is aimed at gracefully being able to extend ASDF's > canonical metadata properties. > > On 29 Apr 2021, at 13:00, Marco Antoniotti wrote: > > Hi Robert > > Isn't the :properties slot already there? I just used it (a month ago) > to add an ASDF DOCUMENT op to HELambdaP. Worked like a charm once I got > the hang of it and it seals the general ASDF machinery from random stuff. > > Marco > > > On Thu, Apr 29, 2021 at 6:13 PM Robert Goldman <rpgold...@sift.info> > wrote: > >> ASDF checks to make sure all of the initargs are defined when parsing a >> defsystem. This is good for catching errors, but is terrible for >> extensibility. This means that any attempt to add additional metadata will >> be backwards incompatible. >> >> I can think of two ways to fix this: >> >> 1. >> >> Add a "garbage can" slot to component that will be filled with a >> property list, and allow programmers to do whatever they want here. This >> doesn't seem great to me. >> 2. >> >> Add a new defsystem parsing error class that is >> unknown-component-property, raise it when an unknown property is >> encountered and allow the user to continue, discarding the initarg and >> accompanying value. >> >> The second alternative is what I favor. It isn't great, because it will >> only maintain extensibility going forward, but I think it's the best we can >> do. >> >> I suppose that we could also add an initarg to tell ASDF to continue such >> errors silently. I'd be inclined to suggest that this take an ASDF version >> expression as value, so that the error is quietly ignored only by ASDF >> versions below that. This means that the property will start to be checked >> when it has become authoritative. >> >> Note that for one's own system and component subclasses, the set of >> initargs can be extended without any monkeying around. >> > > > -- > Marco Antoniotti, Associate Professor tel. +39 - 02 64 48 79 01 > DISCo, Università Milano Bicocca U14 2043 http://dcb.disco.unimib.it > Viale Sarca 336 > http://cdac2021.lakecomoschool.org > I-20126 Milan (MI) ITALY > > -- Marco Antoniotti, Associate Professor tel. +39 - 02 64 48 79 01 DISCo, Università Milano Bicocca U14 2043 http://dcb.disco.unimib.it Viale Sarca 336 http://cdac2021.lakecomoschool.org I-20126 Milan (MI) ITALY
