resolver.rb in loxxy-0.1.14

- old
+ new

@@ -24,14 +24,19 @@
 
       # An indicator that tells we're in the middle of a function declaration
       # @return [Symbol] must be one of: :none, :function
       attr_reader :current_function
 
+      # An indicator that tells we're in the middle of a class declaration
+      # @return [Symbol] must be one of: :none, :class
+      attr_reader :current_class
+
       def initialize
         @scopes = []
         @locals = {}
         @current_function = :none
+        @current_class = :none
       end
 
       # Given an abstract syntax parse tree visitor, launch the visit
       # and execute the visit events in the output stream.
       # @param aVisitor [AST::ASTVisitor]
@@ -57,14 +62,20 @@
       def before_class_stmt(aClassStmt)
         declare(aClassStmt.name)
       end
 
       def after_class_stmt(aClassStmt, aVisitor)
+        previous_class = current_class
+        @current_class = :class
         define(aClassStmt.name)
+        begin_scope
+        define('this')
         aClassStmt.body.each do |fun_stmt|
           resolve_function(fun_stmt, :method, aVisitor)
         end
+        end_scope
+        @current_class = previous_class
       end
 
       def before_for_stmt(aForStmt)
         before_block_stmt(aForStmt)
       end
@@ -136,9 +147,21 @@
       end
 
       def after_get_expr(aGetExpr, aVisitor)
         # Evaluate object part
         aGetExpr.object.accept(aVisitor)
+      end
+
+      def before_this_expr(_thisExpr)
+        if current_class == :none
+          msg = "Error at 'this': Can't use 'this' outside of a class."
+          raise StandardError, msg
+        end
+      end
+
+      def after_this_expr(aThisExpr, aVisitor)
+        # 'this' behaves closely to a local variable
+        resolve_local(aThisExpr, aVisitor)
       end
 
       # function declaration creates a new scope for its body & binds its parameters for that scope
       def before_fun_stmt(aFunStmt, aVisitor)
         declare(aFunStmt.name)