1 files changed, 48 insertions, 0 deletions
diff --git a/spec/rubyspec/language/regexp/back-references_spec.rb b/spec/rubyspec/language/regexp/back-references_spec.rb
new file mode 100644
index 0000000000..607f4463fd
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+++ b/spec/rubyspec/language/regexp/back-references_spec.rb
@@ -0,0 +1,48 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../../fixtures/classes', __FILE__)
+
+describe "Regexps with back-references" do
+  it "saves match data in the $~ pseudo-global variable" do
+    "hello" =~ /l+/
+    $~.to_a.should == ["ll"]
+  end
+
+  it "saves captures in numbered $[1-9] variables" do
+    "1234567890" =~ /(1)(2)(3)(4)(5)(6)(7)(8)(9)(0)/
+    $~.to_a.should == ["1234567890", "1", "2", "3", "4", "5", "6", "7", "8", "9", "0"]
+    $1.should == "1"
+    $2.should == "2"
+    $3.should == "3"
+    $4.should == "4"
+    $5.should == "5"
+    $6.should == "6"
+    $7.should == "7"
+    $8.should == "8"
+    $9.should == "9"
+  end
+
+  it "will not clobber capture variables across threads" do
+    cap1, cap2, cap3 = nil
+    "foo" =~ /(o+)/
+    cap1 = [$~.to_a, $1]
+    Thread.new do
+      cap2 = [$~.to_a, $1]
+      "bar" =~ /(a)/
+      cap3 = [$~.to_a, $1]
+    end.join
+    cap4 = [$~.to_a, $1]
+    cap1.should == [["oo", "oo"], "oo"]
+    cap2.should == [[], nil]
+    cap3.should == [["a", "a"], "a"]
+    cap4.should == [["oo", "oo"], "oo"]
+  end
+
+  it "supports \<n> (backreference to previous group match)" do
+    /(foo.)\1/.match("foo1foo1").to_a.should == ["foo1foo1", "foo1"]
+    /(foo.)\1/.match("foo1foo2").should be_nil
+  end
+
+  it "resets nested \<n> backreference before match of outer subexpression" do
+    /(a\1?){2}/.match("aaaa").to_a.should == ["aa", "a"]
+  end
+end