Remove redudant eval() call.

diff --git a/pylambda.py b/pylambda.py
index 941f1c1..39743c7 100755
--- a/pylambda.py
+++ b/pylambda.py
@@ -160,7 +160,7 @@ if __name__ == "__main__":
       break
     if s == "" : continue
     try:
-      value = yacc.parse(s).eval().eval()
+      value = yacc.parse(s).eval()
       print ": %s  :: %s" % (value, typeof(value))
       set_old_value(value)
     except TypeError,e: