David said:
Hi --
An open question for Matz:
Is anything disappearing from Ruby in 2.0? Not that I have a very big
list of things I want removed
but I'm wondering, for example,
about the Perl-like special variables. And just wondering generally
if there's anything in that category.
If the perlish globals are going away, then that suggests another
possibility that would make the remaining globals more regular. I often
have to look up which globals are per-thread (and this was especially
true when I was starting out with ruby). What if the name of the global
determined in a very simple way whether is was per-thread or not?
For example, the rule could be: all globals matching /\$_\w*/ are
per-thread. All others are per-process. That's consistent with the
current use of $_, which is per-thread.
What breaks? Well, if you take out all the perlish variables from the
list in the Pickaxe (pp.216-218), the only variable whose behavior would
change is $SAFE. So that would have to be replaced with $_SAFE, or left
as a special case (perhaps with a warning, and expiring after a while).
I'd rather remember one special case than two pages of them. The
standard library is unaffected, aside from any use of $SAFE, since there
are no variables in it that match /\$_\w+/. Same goes for all the RAA
projects that I've downloaded.
This change would also make it easy to work with user-defined thread
local variables. Instead of
Thread.new {
Thread.current[:foo] = 3
}
you could simply do
Thread.new {
$_foo = 3
}
I guess that's probably more efficient, too, since it saves a method call.
