public object VisitProgram(AST.Program Node)
{
this.CallStack.Push(new StackFrame("global", 1));
foreach (object Child in Node.Compound.Children)
{
if (!(Child is AST.SubroutineDeclaration))
{
this.Visit(Child);
}
else
{
AST.SubroutineDeclaration subroutine = Child as AST.SubroutineDeclaration;
string subname = (string)subroutine.SubroutineName.Value;
if (null != subroutine.Body)
{
this.Subroutines.Add(subname, subroutine);
}
}
}
object result = this.VisitSubroutineDeclaration(this.Subroutines["main"]);
this.CallStack.Pop();
return(result);
}
public object VisitSubroutineDeclaration(AST.SubroutineDeclaration Node, AST.Call Call = null)
{
StackFrame sf = new StackFrame(
(string)Node.SubroutineName.Value,
this.CallStack.Peek().Level + 1,
Node.Params,
this.CallStack.Peek());
if (null != Call)
{
for (int i = 0; i < Call.Params.Count; i++)
{
string varname = (string)Node.Params[i].VariableNode.Value;
string vartype = (string)Node.Params[i].TypeNode.Value;
object value = this.ConvertAppr(this.Visit(Call.Params[i]), vartype);
sf.Assign(varname, value);
}
}
this.CallStack.Push(sf);
this.VisitCompound(Node.Body);
if (null == this.CallStack.Peek().ret)
{
this.Error(
String.Format(Messages.MISSING_RETURN_STMT,
Node.SubroutineName.Value),
Node.SubroutineName.Token.Position);
}
object ret = (this.CallStack.Pop()).ret;
string rettype = (string)Node.ReturnType.Value;
return(this.ConvertAppr(ret, rettype));
}