forwardable/impl.rb

* lib/forwardable/impl.rb (_valid_method?, _compile_method):
  extract to separate implementation specific part.
  [ruby-core:78138] [Bug #12938]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56848 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/rubyvm/extconf.rb

@@ -0,0 +1 @@
+create_makefile("rubyvm")

ext/rubyvm/lib/forwardable/impl.rb

@@ -0,0 +1,19 @@
+# :stopdoc:
+module Forwardable
+  FILTER_EXCEPTION = ""
+
+  def self._valid_method?(method)
+    iseq = RubyVM::InstructionSequence.compile("().#{method}", nil, nil, 0, false)
+  rescue SyntaxError => e
+    false
+  else
+    iseq.to_a.dig(-1, 1, 1, :mid) == method.to_sym
+  end
+
+  def self._compile_method(src, file, line)
+    RubyVM::InstructionSequence.compile(src, file, file, line,
+               trace_instruction: false,
+               tailcall_optimization: true)
+      .eval
+  end
+end