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@@ -93,16 +93,31 @@ module BusScheme
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     # allows for (mylist 4) => (nth mylist 4)
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     def call(nth)
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-      nth = nth.car if nth.is_a? Cons # TODO: remove?
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+      # Allow lists to be called with an argument list or a fixnum arg
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+      nth = nth.car if nth.is_a? Cons
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       nth == 0 ? @car : @cdr.call(nth - 1)
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     end
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     include Callable
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+
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+    # support for methods like caddar
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+    def method_missing(sym)
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+      sym = sym.to_s
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+      raise NoMethodError unless sym =~ /^c([ad]+)r/
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+      case sym
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+      when 'car'
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+        car
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+      when 'cdr'
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+        cdr
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+      when /^ca/
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+        send(sym.sub('a', '')).car
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+      when /^cd/
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+        send(sym.sub('d', '')).cdr
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+      end
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+    end
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   end
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   def cons(car = nil, cdr = nil)
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     Cons.new(car, cdr)
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   end
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   module_function :cons
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-
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-  # TODO: use method_missing to handle stuff like caadadadar
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 end

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@@ -44,4 +44,11 @@ class TestCons < Test::Unit::TestCase
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     # assert_evals_to cons(true, cons(false)), "'(#t #f)"
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     # assert_evals_to cons(true, false), "'(#t . #f)"
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   end
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+
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+  def test_caadar_stuff
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+    list = (0 .. 9).to_a
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+    assert_equal 2, list.to_list.caddr
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+    list[3] = ['a', 'b', 'c']
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+    assert_equal 'b', list.to_list.cadadddr
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+  end
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 end