On Thu, 23 Apr 2020, Jani Nikula wrote: > On Thu, 23 Apr 2020, Nicolas Pitre <nico@xxxxxxxxxxx> wrote: > > This might appear to be a strange concept, but sometimes we want > > a dependency to be conditionally applied. One such case is currently > > expressed with: > > > > depends on FOO || !FOO > > > > This pattern is strange enough to give one's pause. Given that it is > > also frequent, let's make the intent more obvious with some syntaxic > > sugar by effectively making dependencies optionally conditional. > > > > This also makes the kconfig language more uniform. > > Thanks, I prefer this over all the previous proposals. Versatile yet > self-explanatory. > > > Signed-off-by: Nicolas Pitre <nico@xxxxxxxxxxx> > > > > diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst > > index d0111dd264..0f841e0037 100644 > > --- a/Documentation/kbuild/kconfig-language.rst > > +++ b/Documentation/kbuild/kconfig-language.rst > > @@ -114,7 +114,7 @@ applicable everywhere (see syntax). > > This is a shorthand notation for a type definition plus a value. > > Optionally dependencies for this default value can be added with "if". > > > > -- dependencies: "depends on" <expr> > > +- dependencies: "depends on" <expr> ["if" <expr>] > > > > This defines a dependency for this menu entry. If multiple > > dependencies are defined, they are connected with '&&'. Dependencies > > @@ -130,6 +130,16 @@ applicable everywhere (see syntax). > > bool "foo" > > default y > > > > + The dependency definition itself may be conditional by appending "if" > > + followed by an expression. If such expression is false (n) then this > > + dependency is ignored. One possible use case is: > > + > > + config FOO > > + tristate > > + depends on BAZ if BAZ != n > > I presume this is the same as > > depends on BAZ if BAZ > > which makes me wonder if that should be the example. At least current > usage for select is predominantly > > select FOO if BAR > > without "!= n". Yes, it is the same thing. I prefer making the documentation a little more explicit than necessary so the explanation is really obvious. Nicolas
