diff --git a/lib/risc/builder.rb b/lib/risc/builder.rb
index 448bd5ff..80a467a8 100644
--- a/lib/risc/builder.rb
+++ b/lib/risc/builder.rb
@@ -50,13 +50,20 @@ module Risc
     # infer the type from a symbol. In the simplest case the sybbol is the class name
     # But in building sometimes variations are needed, so next_message or caller work
     # too (and return Message)
+    # A general "_reg" or "_obj" at the end of the name will be removed
     # An error is raised if the symbol/object can not be inferred
     def infer_type( name )
-      name = :word if name == :name
-      name = :message if name == :next_message
-      name = :message if name == :caller
-      name = :named_list if name == :arguments
-      sym = name.to_s.camelise.to_sym
+      as_string = name.to_s
+      parts = as_string.split("_")
+      if(parts.last == "reg" or parts.last == "obj")
+        parts.pop
+        as_string = parts.join("_")
+      end
+      as_string = "word" if as_string == "name"
+      as_string = "message" if as_string == "next_message"
+      as_string = "message" if as_string == "caller"
+      as_string = "named_list" if as_string == "arguments"
+      sym = as_string.camelise.to_sym
       clazz = Parfait.object_space.get_class_by_name(sym)
       raise "Not implemented/found object #{name}:#{sym}" unless clazz
       return clazz.instance_type
diff --git a/test/risc/test_builder.rb b/test/risc/test_builder.rb
index f50c8f55..adc35735 100644
--- a/test/risc/test_builder.rb
+++ b/test/risc/test_builder.rb
@@ -98,20 +98,4 @@ module Risc
       assert_equal :Space , op.left.type.class_name
     end
   end
-  class TestCompilerBuilder < MiniTest::Test
-
-    def setup
-      Parfait.boot!
-      Risc.boot!
-      @init = Parfait.object_space.get_init
-      @compiler = Risc::MethodCompiler.new( @init )
-      @builder  = @compiler.compiler_builder(@init)
-    end
-    def test_inserts_built
-      r1 = RegisterValue.new(:r1 , :Space)
-      @builder.build{ space << r1 }
-      assert_equal Transfer , @compiler.risc_instructions.next.class
-    end
-
-  end
 end
diff --git a/test/risc/test_builder1.rb b/test/risc/test_builder1.rb
new file mode 100644
index 00000000..1b3aac16
--- /dev/null
+++ b/test/risc/test_builder1.rb
@@ -0,0 +1,20 @@
+require_relative "../helper"
+
+module Risc
+  class TestCompilerBuilder < MiniTest::Test
+
+    def setup
+      Parfait.boot!
+      Risc.boot!
+      @init = Parfait.object_space.get_init
+      @compiler = Risc::MethodCompiler.new( @init )
+      @builder  = @compiler.compiler_builder(@init)
+    end
+    def test_inserts_built
+      r1 = RegisterValue.new(:r1 , :Space)
+      @builder.build{ space << r1 }
+      assert_equal Transfer , @compiler.risc_instructions.next.class
+    end
+
+  end
+end
diff --git a/test/risc/test_builder2.rb b/test/risc/test_builder2.rb
new file mode 100644
index 00000000..3929d4ae
--- /dev/null
+++ b/test/risc/test_builder2.rb
@@ -0,0 +1,39 @@
+require_relative "../helper"
+
+module Risc
+  class TestBuilderInfer < MiniTest::Test
+
+    def setup
+      Parfait.boot!
+      Risc.boot!
+      @init = Parfait.object_space.get_init
+      @compiler = Risc::MethodCompiler.new( @init )
+      @builder  = @compiler.compiler_builder(@init)
+    end
+    def test_list
+      assert_equal :List , @builder.infer_type(:list).class_name
+    end
+    def test_name
+      assert_equal :Word , @builder.infer_type(:name).class_name
+    end
+    def test_word
+      assert_equal :Word , @builder.infer_type(:word).class_name
+    end
+    def test_caller
+      assert_equal :Message , @builder.infer_type(:caller).class_name
+    end
+    def test_caller_reg
+      assert_equal :Message , @builder.infer_type(:caller_reg).class_name
+    end
+    def test_caller_obj
+      assert_equal :Message , @builder.infer_type(:caller_obj).class_name
+    end
+    def test_message
+      assert_equal :Message , @builder.infer_type(:message).class_name
+    end
+    def test_next_message
+      assert_equal :Message , @builder.infer_type(:next_message).class_name
+    end
+
+  end
+end