On Tue, 8 Nov 2016 19:30:28 -0500 Michael Orlitzky <m...@gentoo.org> wrote:
> On 11/08/2016 10:47 AM, Michał Górny wrote: > > > > Strictly speaking, we don't have to since the lexing should be > > predictable enough. Of course, mistakes like missing version following > > the operator would result in curious errors. > > > > The major problem with spaces I see is that it means we end up having > > an additional [use] block floating following them. > > > > I was also thinking that the logical operators could be infix, and then > you need the commas to avoid precedence issues with the implicit-and, > which is written " ". The [use] blocks could be moved next to the > package name I guess. If we were to rewrite the dependency syntax from > scratch, what would it look like? My first attempt would look something > like, > > DEPEND="dev-lang/perl, > net-misc/wget || net-misc/curl, I don't think this is really more readable than || ( ... ). And in most cases, it would be longer to write too. > apache2? ( www-servers/apache[apache2_modules_cgi] >= 2.4 ), In what order is that interpreted? Remember that you aren't allowed to reference USE flags not in IUSE without (+) and (-). So if things are parsed left-to-right, you may end up applying an invalid USE restriction before the version restriction. > ssl? ( > !libressl? ( dev-libs/openssl:=0 ), > libressl? ( dev-libs/libressl:= ) > )" > > The reason I'm entertaining this is because the more operators we add, > the more awkward the prefix notation gets. If we had spaces around the > operators, they wouldn't need to consist of invalid package characters, > and we could do something like, > > DEPEND="app-foo/bar in [1,2]" > > to request a version in the closed interval [1,2]. For (half) exclusive > ranges, we could have (1,2), (1,2], and [1,2) -- there's no need to > reinvent that particular wheel. We know that "in" surrounded by spaces > is an operator, and we know the types of its two arguments. With prefix > notation, you'd have > > DEPEND="inapp-foo/bar[1,2]" #fail It's not prefix notation. Prefix would be: in[1,2]app-foo/bar > There's always ∈, but you still have to figure out what's in the brackets. > > It's fun to brainstorm, but there are probably numerous problems with > every syntax I've imagined, and the only way to have a meaningful > discussion about one of them would be to create a reference > implementation and migrate some ebuilds. Retraining hundreds of > developers and users is a high bar to set without being damn sure that > we've got it right. -- Best regards, Michał Górny <http://dev.gentoo.org/~mgorny/>
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