refactor a bit for upcoming delegations

must get method to be private
more tell, not ask

lib/risc/builder.rb

@@ -171,7 +171,11 @@ module Risc
     end
   end
 
-  # The first arg is a class name (possibly lowercase) and the second an instance variable name.
+  # resolve a symbol to a type. 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)
+  # Also objects work, in which case the instance_type of their class is returned
+  # An error is raised if the symbol/object can not be resolved
   def self.resolve_type( object , compiler )
     object = object.type if object.is_a?(RegisterValue)
     case object
@@ -205,7 +209,8 @@ module Risc
   # Third arg, compiler, is only needed to resolve receiver/arguments/frame
   def self.resolve_to_index(object , variable_name ,compiler = nil)
     return variable_name if variable_name.is_a?(Integer) or variable_name.is_a?(RegisterValue)
-    type = resolve_type(object , compiler)
+    type = compiler.resolve_type( object) if compiler
+    type = resolve_type(object , compiler) unless type
     index = type.variable_index(variable_name)
     raise "Index not found for #{variable_name} in #{object} of type #{type}" unless index
     return index

lib/risc/method_compiler.rb

@@ -69,6 +69,21 @@ module Risc
       ret
     end
 
+    # resolve a symbol to a type. Allowed symbols are :frame , :receiver and arguments
+    # which return the respective types, otherwise nil
+    def resolve_type( name )
+      case name
+      when :frame
+        return @method.frame_type
+      when :arguments
+        return @method.arguments_type
+      when :receiver
+        return @method.self_type
+      else
+        return nil
+      end
+    end
+
     # convert the given mom instruction to_risc and then add it (see add_code)
     # continue down the instruction chain unti depleted
     # (adding moves the insertion point so the whole mom chain is added as a risc chain)

test/mom/instruction/helper.rb

@@ -2,6 +2,11 @@ require_relative '../helper'
 
 module Mom
   class CompilerMock
+    # resolve a symbol to a type. Allowed symbols are :frame , :receiver and arguments
+    # which return the respective types, otherwise nil
+    def resolve_type( name )
+        return nil
+    end
     def use_reg( type )
       Risc.tmp_reg(type , nil)
     end