1 files changed, 44 insertions, 0 deletions
diff --git a/lib/rubygems/util/list.rb b/lib/rubygems/util/list.rb
new file mode 100644
index 0000000000..9f540adcc1
--- /dev/null
+++ b/lib/rubygems/util/list.rb
@@ -0,0 +1,44 @@
+module Gem
+  List = Struct.new(:value, :tail)
+
+  class List
+    def each
+      n = self
+      while n
+        yield n.value
+        n = n.tail
+      end
+    end
+
+    def to_a
+      ary = []
+      n = self
+      while n
+        ary.unshift n.value
+        n = n.tail
+      end
+
+      ary
+    end
+
+    def find
+      n = self
+      while n
+        v = n.value
+        return v if yield(v)
+        n = n.tail
+      end
+
+      nil
+    end
+
+    def prepend(value)
+      List.new value, self
+    end
+
+    def self.prepend(list, value)
+      return List.new(value) unless list
+      List.new value, list
+    end
+  end
+end