1 files changed, 91 insertions, 0 deletions
diff --git a/lib/racc/iset.rb b/lib/racc/iset.rb
new file mode 100644
index 0000000000..a79e709f9c
--- /dev/null
+++ b/lib/racc/iset.rb
@@ -0,0 +1,91 @@
+#
+# $Id: de638608cfd72d3ed9819d87b65a89ee6a57b589 $
+#
+# Copyright (c) 1999-2006 Minero Aoki
+#
+# This program is free software.
+# You can distribute/modify this program under the terms of
+# the GNU LGPL, Lesser General Public License version 2.1.
+# For details of the GNU LGPL, see the file "COPYING".
+#
+
+module Racc
+
+  # An "indexed" set.  All items must respond to :ident.
+  class ISet
+
+    def initialize(a = [])
+      @set = a
+    end
+
+    attr_reader :set
+
+    def add(i)
+      @set[i.ident] = i
+    end
+
+    def [](key)
+      @set[key.ident]
+    end
+
+    def []=(key, val)
+      @set[key.ident] = val
+    end
+
+    alias include? []
+    alias key? []
+
+    def update(other)
+      s = @set
+      o = other.set
+      o.each_index do |idx|
+        if t = o[idx]
+          s[idx] = t
+        end
+      end
+    end
+
+    def update_a(a)
+      s = @set
+      a.each {|i| s[i.ident] = i }
+    end
+
+    def delete(key)
+      i = @set[key.ident]
+      @set[key.ident] = nil
+      i
+    end
+
+    def each(&block)
+      @set.compact.each(&block)
+    end
+
+    def to_a
+      @set.compact
+    end
+
+    def to_s
+      "[#{@set.compact.join(' ')}]"
+    end
+
+    alias inspect to_s
+
+    def size
+      @set.nitems
+    end
+
+    def empty?
+      @set.nitems == 0
+    end
+
+    def clear
+      @set.clear
+    end
+
+    def dup
+      ISet.new(@set.dup)
+    end
+  
+  end   # class ISet
+
+end   # module Racc