add whilesmall_step

1 files changed, 20 insertions, 0 deletions

diff --git a/simple/simple.rb b/simple/simple.rb
index a31e001..a045347 100644
--- a/simple/simple.rb
+++ b/simple/simple.rb
@@ -178,7 +178,27 @@ class Sequence < Struct.new(:first, :second)
       else
         reduced_first, reduced_environment = first.reduce(environment)
         [Sequence.new(reduced_first, second), reduced_environment]
+    end
+  end
+end
+
+class While < Struct.new(:condition,:body)
+  def to_s
+    "while (#{condition} { #{body} })"
+  end
+
+  def inspect
+    "<#{self}>"
+  end
+
+  def reducible?
+    true
+  end
+  
+  def reduce(environment)
+    [If.new(condition,Sequence.new(body,self),DoNothing.new), environment]
   end
+end
 
 class Machine < Struct.new(:statement, :environment)
   def step