Bug #17268
Updated by ko1 (Koichi Sasada) about 4 years ago
Ractors can't access global variables, but some special global variables should be accessed.
There are several types.
## Proposal
(1) Read-only global variables
```ruby
# process-local (readonly): other commandline parameters
'$-p' => $-p,
'$-l' => $-l,
'$-a' => $-a,
# process-local (readonly): getpid
'$$' => $$,
```
(2) scope local variables
```ruby
# thread local: process result
'$?' => $?,
# scope local: match
'$~' => $~.inspect,
'$&' => $&,
'$`' => $`,
'$\'' => $',
'$+' => $+,
'$1' => $1,
# scope local: last line
'$_' => $_,
# scope local: last backtrace
'$@' => $@,
'$!' => $!,
```
(3) Ractor local variables
```ruby
# ractor-local (derived from created ractor): debug
'$DEBUG' => $DEBUG,
'$-d' => $-d,
# ractor-local (derived from created ractor): verbose
'$VERBOSE' => $VERBOSE,
'$-w' => $-w,
'$-W' => $-W,
'$-v' => $-v,
# ractor local: stdin, out, err
'$stdin' => $stdin.inspect,
'$stdout' => $stdout.inspect,
'$stderr' => $stderr.inspect,
```
Implementation: https://github.com/ruby/ruby/pull/3670
I'll merge it soon.
## Discussion
* only accessible from main ractor?
* `$0`:
* ARGV, ARGF, `$.`
* only accessible from main ractor because they will be obsolete
* `$, $/ $; $\`
* So difficult: `$" / $LOADED_FEATURES` and `$: / $LOAD_PATH`