Hi Ludo, nice feature! On Sun, 15 Nov 2020 17:33:28 +0100 Ludovic Courtès wrote: > An important question: do we have examples of packages for which we’d > like to have parameters? For the embedded/flash rom side: * Enable/disable building the documentation. I really don't need a 40 MiB manual stored onto a 16 MiB firmware flash chip. If that's better done as an extra output, fair enough. * Enable/disable obscure dependencies: Library packages that pull in 400 MiB Qt into the closure for a thing no one (TM) uses should probably provide a switch to disable that GUI. Sometimes a package provides multiple GUIs for different toolkits, in which case one should be able to choose one toolkit and not build for the others. * No, even in 2020, I won't start using AmigaFS, NFSv3 and whatever old protocol/format is still around and superseded by other protocols. The gexp-functionality of being able to select individual files of a package is already very useful for use cases an embedded developer would have (and that's there for a long time already). So that's nice! For the kind of feature flags I have in mind, it usually means I don't want to have the feature *anywhere*--for example, if I don't want to have Qt or Kerberos or whatever, that's because I want to save the space and thus it should be able to be *globally* specified--at least per profile. It doesn't help one bit for space savings if package A doesn't pull in Kerberos or latex or or Haskell bindings for a Raspberry Pi serial port library (guess why that's oddly specific ;) ), but package B does. However, sometimes using static libraries is better and there's no reason to build the shared libraries. But that's very much local to whatever I'm trying to do (at least local to a profile if not package). I would advise against doing a grep -r -- --enable and introducing all those as parameters. Rather I would check the closure of stuff and if the closure goes from 1200 MiB to 50 MiB, chances are a parameter would be nice there :) I guess the kind of flags I envision would be set at profile level. From experience with Gentoo before I can tell you that the combinatory explosion is a real problem and most of the "more advanced" (toggled more switches :) ) combinations did not work the majority of the time.