checkpointing on the mad road to register allocation

lib/ast/basic_expressions.rb

@@ -14,7 +14,7 @@ module Ast
       value.to_s
     end
     def compile context , into
-      Vm::Integer.new value
+      Vm::IntegerConstant.new value
     end
     def attributes
       [:value]

lib/ast/function_expression.rb

@@ -18,16 +18,20 @@ module Ast
     end
     def compile context , into 
       raise "function does not compile into anything #{self}" if into
-      parent_locals = context.locals
-      context.locals = {}
       args = []
+      locals = {}
       params.each_with_index do |param , index|
         arg = param.name
         arg_value = Vm::Integer.new(index)
-        context.locals[arg] = arg_value
+        locals[arg] = arg_value
         args << arg_value
       end
       function = Vm::Function.new(name , args )
+      parent_locals = context.locals
+      parent_function = context.function
+      context.locals = locals
+      context.function = function
+
       context.program.add_function function
       into = function.entry
       block.each do |b|
@@ -41,6 +45,7 @@ module Ast
         puts compiled.inspect
       end
       context.locals = parent_locals
+      context.function = parent_function
       function
     end
 

lib/ast/operator_expressions.rb

@@ -43,10 +43,15 @@ module Ast
       "#{left} #{operator} #{right}"
     end
     def compile context , into
+      puts "compile #{to_s}"
       r_val = right.compile(context , into)
-      
       if operator == "="    # assignemnt
         raise "Can only assign variables, not #{left}" unless left.is_a?(NameExpression) 
+        if r_val.is_a? Vm::IntegerConstant
+          puts context.attributes.keys.join(" ")
+          next_register = context.function.next_register
+          r_val = Vm::Integer.new(next_register).load( into , r_val )
+        end
         context.locals[left.name] = r_val
         return r_val
       end
@@ -54,9 +59,9 @@ module Ast
 
       case operator
       when ">"
-        code = l_val.less_or_equal r_val
+        code = l_val.less_or_equal into , r_val
       when "+"
-        code = l_val.plus r_val
+        code = l_val.plus into , r_val
       else
         raise "unimplemented operator #{operator} #{self}"
       end