new field access code and test. wip as field def broken

lib/bosl/compiler/field_access.rb

@@ -0,0 +1,28 @@
+module Bosl
+  Compiler.class_eval do
+
+    def on_field_access expression
+      puts expression.inspect
+      receiver_ast , field_ast = *expression
+      receiver = receiver_ast.first_from(:name)
+      field_name = field_ast.first_from(:name)
+
+      case receiver
+      when :self
+        for_class = self.method.for_class
+        index = for_class.object_layout.variable_index(field_name)
+        raise "field access, but no such field:#{field_name} for class #{for_class.name}"
+        method.source.add_code Virtual::Set.new( Virtual::ArgSlot.new(:int,index ) , ret)
+
+      when :message
+        #message Slot
+        raise "message not yet"
+      else
+        #arg / frame Slot
+        raise "frame not implemented"
+      end
+
+      Virtual::Return.new( value )
+    end
+  end
+end