add rewriting of operator assignment

foo += 1 becomes foo = foo + 1 in vool

Guardfile

@@ -22,6 +22,9 @@ guard :minitest , all_on_start: false do   # with Minitest::Unit
   #parfait type tests have a whole directory
   watch(%r{^lib/parfait/type.rb}) { Dir["test/parfait/type/test_*.rb"] }
 
+  # ruby compiler tests have a whole directory
+  watch(%r{^lib/vool/ruby_compiler.rb}) { Dir["test/vool/ruby_compiler/test_*.rb"] }
+
   # Vool to_mom compile process +   # Ruby to vool compile process
   watch(%r{^lib/vool/statements/(.+)_statement.rb}) { |m|
     [ Dir["test/vool/to_mom/test_#{m[1]}*.rb"] , "test/vool/statements/test_#{m[1]}.rb"] }

lib/vool/ruby_compiler.rb

@@ -10,6 +10,7 @@ module Vool
   # The next step is then to normalize the code and then finally to compile
   # to the next level down, MOM (Minimal Object Machine)
   class RubyCompiler < AST::Processor
+  include AST::Sexp
 
     def self.compile(input)
       ast = Parser::Ruby22.parse( input )
@@ -132,6 +133,16 @@ module Vool
       IvarAssignment.new(instance_name(name),value)
     end
 
+    def on_op_asgn(expression)
+      ass , op , exp = *expression
+      name = ass.children[0]
+      a_type = ass.type.to_s[0,3]
+      rewrite = s( a_type + "sgn" ,
+                  name ,
+                  s(:send , s( a_type + "r" , name ) , op , exp ) )
+      process(rewrite)
+    end
+
     def on_return statement
       return_value = process(statement.children.first)
       ReturnStatement.new( return_value )

test/vool/ruby_compiler/test_ivar_assignment.rb

@@ -1,7 +1,7 @@
 require_relative "helper"
 
 module Vool
-  class TestAssignment < MiniTest::Test
+  class TestIvarAssignment < MiniTest::Test
 
     def test_local
       lst = RubyCompiler.compile( "foo = bar")

test/vool/ruby_compiler/test_local_assignment.rb

@@ -1,7 +1,7 @@
 require_relative "helper"
 
 module Vool
-  class TestLocal < MiniTest::Test
+  class TestLocalAssignment < MiniTest::Test
 
     def test_local
       lst = RubyCompiler.compile( "foo = bar")

test/vool/ruby_compiler/test_op_assignment.rb

@@ -0,0 +1,39 @@
+require_relative "helper"
+
+module Vool
+  module OpAss
+    def test_local_name
+      assert_equal :foo , @lst.name
+    end
+    def test_local_value
+      assert_equal SendStatement , @lst.value.class
+    end
+    def test_local_method
+      assert_equal :+ , @lst.value.name
+    end
+    def test_local_receiver
+      assert_equal :foo , @lst.value.receiver.name
+    end
+    def test_local_receiver
+      assert_equal 5 , @lst.value.arguments.first.value
+    end
+  end
+  class TestLocalOpAssign < MiniTest::Test
+    include OpAss
+    def setup
+      @lst = RubyCompiler.compile( "foo += 5")
+    end
+    def test_local_ass
+      assert_equal LocalAssignment , @lst.class
+    end
+  end
+  class TestIvarOpAssign < MiniTest::Test
+    include OpAss
+    def setup
+      @lst = RubyCompiler.compile( "@foo += 5")
+    end
+    def test_ivar_ass
+      assert_equal IvarAssignment , @lst.class
+    end
+  end
+end