Sorry, quoting myself...
In a message dated Mon, 7 Jan 2008, Trey Harris writes:
given $?OS {
when m:i:/win/ { use Foo in WinFoo.pm }
when m:i:/nix/ { use Foo in UnixLikeFoo.pm }
}
It strikes me that $?OS and $?OSVER should probably not be strings (as
they now are in Pugs) and should be objects--in fact, they can both be the
same object, just with different stringifications. Auto-instantiated
singletons of classes named for the OS, to be precise.
That way, you could do Config-and OS-specific-type stuff through the $?OS
object--which is nice, though not that important--but better yet you can
do
given $?OS {
when Windows { ... }
when MacOS { ... }
when Linux { ... }
when Unix { ... }
default { ... }
}
Rather than having to do string-matching (and one would assume that Linux
and MacOS are subtypes of Unix, etc.)
Then we can have roles that describe cross-cutting behavior of various
OS's (like POSIX):
my &trytolink;
give $?OS {
when OS::HasSymlinks { &trytolink := &*symlink; }
when OS::HasLinks { &trytolink := &*link; }
default { &trytolink :=
-> ($old, $new) { fail X::LinkNotAvailable }
}
}
# (Aside: Is there some way to do create a two-argument sub that ignores
# its arguments? Would -> (undef, undef) or -> (*, *) or -> (Any, Any)
# work?)
So $?OS isn't "the type of OS", it's *the OS*, and you can manipulate the
OS through it.
Thoughts?
Trey
