From 85a9520118f5dbbaab8a5801815c605c1bb799c1 Mon Sep 17 00:00:00 2001
From: Shugo Maeda <shugo@ruby-lang.org>
Date: Tue, 23 Oct 2012 11:29:34 +0900
Subject: [PATCH] don't use RubyVM if it's not available.

---
 lib/immutable.rb    | 16 ++++++++++------
 test/test_helper.rb | 20 ++++++++++++--------
 2 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/lib/immutable.rb b/lib/immutable.rb
index d71485a..ad15a71 100644
--- a/lib/immutable.rb
+++ b/lib/immutable.rb
@@ -2,11 +2,13 @@
 module Immutable
 end
 
-old_compile_option = RubyVM::InstructionSequence.compile_option
-RubyVM::InstructionSequence.compile_option = {
-  :tailcall_optimization => true,
-  :trace_instruction => false
-}
+if defined?(RubyVM)
+  old_compile_option = RubyVM::InstructionSequence.compile_option
+  RubyVM::InstructionSequence.compile_option = {
+    :tailcall_optimization => true,
+    :trace_instruction => false
+  }
+end
 begin
   require_relative "immutable/list"
   require_relative "immutable/map"
@@ -16,5 +18,7 @@ module Immutable
   require_relative "immutable/output_restricted_deque"
   require_relative "immutable/deque"
 ensure
-  RubyVM::InstructionSequence.compile_option = old_compile_option
+  if defined?(RubyVM)
+    RubyVM::InstructionSequence.compile_option = old_compile_option
+  end
 end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index d3ab630..84168a4 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -3,14 +3,18 @@
 require "test/unit"
 
 def with_tailcall_optimization
-  old_compile_option = RubyVM::InstructionSequence.compile_option
-  RubyVM::InstructionSequence.compile_option = {
-    :tailcall_optimization => true,
-    :trace_instruction => false
-  }
-  begin
+  if defined?(RubyVM)
+    old_compile_option = RubyVM::InstructionSequence.compile_option
+    RubyVM::InstructionSequence.compile_option = {
+      :tailcall_optimization => true,
+      :trace_instruction => false
+    }
+    begin
+      yield
+    ensure
+      RubyVM::InstructionSequence.compile_option = old_compile_option
+    end
+  else
     yield
-  ensure
-    RubyVM::InstructionSequence.compile_option = old_compile_option
   end
 end