[ruby-core:28870] Improved Delegator for 1.8?

Hello!

I've been trying to improve the perf of Delegator in JRuby (under 1.8
mode) since it's used by WeakRef and we want people to start using
WeakRef instead of id2ref.

1.9 has a new delegate.rb, but I'm not sure it behaves the same as
1.8's Delegator, specifically because it doesn't define all methods
from the object:

~/projects/jruby ➔ ruby -v -rdelegate -e "p
SimpleDelegator.new([]).methods(false)"
ruby 1.8.7 (2008-08-11 patchlevel 72) [universal-darwin10.0]
["insert", "sort", "include?", "&", "size", "to_ary", "clear",
"shuffle", "enum_cons", "replace", "inject", "zip", "pack", "detect",
"min_by", "flatten!", "to_s", "pop", "cycle", "enum_with_index", "*",
"indices", "nitems", "enum_slice", "index", "collect", "+",
"compact!", "max", "=~", "last", "rassoc", "count", "group_by",
"drop", "delete", "delete_at", "one?", "combination", "collect!",
"select", "each_index", "-", "flatten", "fill", "length", "sort_by",
"uniq!", "at", "all?", "choice", "reduce", "reject!", "[]", "take",
"inspect", "shift", "compact", "[]=", "|", "slice!", "find_index",
"max_by", "<<", "transpose", "each", "empty?", "entries", "each_cons",
"map", "rindex", "reverse_each", "member?", "uniq", "push", "to_a",
"minmax", "find", "reverse!", "first", "none?", "delete_if",
"drop_while", "product", "each_with_index", "join", "map!", "reject",
"indexes", "concat", "each_slice", "slice", "grep", "fetch", "<=>",
"min", "assoc", "partition", "permutation", "any?", "values_at",
"take_while", "==", "reverse", "find_all", "===", "unshift", "sort!",
"minmax_by", "shuffle!"]

~/projects/jruby ➔ ruby1.9 -v -rdelegate -e "p
SimpleDelegator.new([]).methods(false)"
ruby 1.9.2dev (2010-03-19 trunk 26976) [x86_64-darwin10.2.0]
[]

I first wrote a native Delegator that's much faster than the one in
delegate.rb, but it behaves more like 1.9. So I worried about
compatibility.

Shown here: http://gist.github.com/340378 is a modified version of the
1.8 Delegator that behaves (almost) exactly the same but runs many
times faster (nearly 100x for a simple benchmark below).

~/projects/jruby ➔ jruby -v -rdelegate -rbenchmark -e "5.times { puts
Benchmark.measure { 10_000.times { SimpleDelegator.new(self) }}}"
jruby 1.5.0.dev (ruby 1.8.7 patchlevel 174) (2010-03-22 81672e5) (Java
HotSpot(TM) Client VM 1.6.0_17) [i386-java]
  0.265000   0.000000   0.265000 (  0.244000)
  0.091000   0.000000   0.091000 (  0.090000)
  0.077000   0.000000   0.077000 (  0.077000)
  0.079000   0.000000   0.079000 (  0.079000)
  0.075000   0.000000   0.075000 (  0.076000)

~/projects/jruby ➔ ../jruby-1.4.0/bin/jruby -v -rdelegate -rbenchmark
-e "5.times { puts Benchmark.measure { 10_000.times {
SimpleDelegator.new(self) }}}"
jruby 1.4.0 (ruby 1.8.7 patchlevel 174) (2009-11-02 69fbfa3) (Java
HotSpot(TM) Client VM 1.6.0_17) [i386-java]
  6.914000   0.000000   6.914000 (  6.884000)
  6.436000   0.000000   6.436000 (  6.436000)
  6.406000   0.000000   6.406000 (  6.406000)
  6.484000   0.000000   6.484000 (  6.484000)
  6.459000   0.000000   6.459000 (  6.459000)

I am wondering if there would be interest in including this in a 1.8.7
update, so libraries using WeakRef won't be penalized compared to
running on JRuby.

- Charlie