Re: [gentoo-dev] New schema language for metadata validation?

[Dirkjan Ochtman]

On Wed, Jan 27, 2016 at 4:43 PM, Michał Górny <mgorny@g.o> wrote:
> Yes, that part makes some sense. Except that it immediately follows
> braces which makes me think it applies only to the thing in the braces.
> Furthermore, the use of {} vs () seems pretty much random, and the &
> is completely unclear what it could mean (I'm not reading the docs
> here!). I look at it and I wonder if that forces some ordering or not,
> if it supports interspersing or not. And finally, the fact that '*'
> follows closing brace on the other end of file does not help
> readability.

A full expression runs from a keyword to the closing brace (e.g.
"element <name> { }"). Parentheses are only used to group expressions
that have the infix operators (one of "," for concatenate -- e.g.,
order --, "|" -- alternative -- and "&" -- interleaving), because
there's no implicit precedence order. Yes, the quantizer comes at the
end. On the other hand, you could rewrite the large expression to be a
named pattern, and then put the quantization after the pattern name if
you prefer that style. That would probably make more sense for large
named patterns. :)

Cheers,

Dirkjan