private bool HandleBuiltInCodeLayout(Code <int> code, ScopeStructure <int> scope)
        {
            switch (code.CodeName.Name)
            {
            case messagePrinterCode:
            case errorPrinterCode:
            case warningPrinterCode:
                return(true);

            case currentOffsetCode:
            case offsetAligner:
                HandleBuiltInOffsetAlign(code, scope);
                return(true);

            case offsetChanger:
                HandleBuiltInOffsetChange(code, scope);
                return(true);

            case offsetPusher:
                HandleBuiltInOffsetPush(code, scope);
                return(true);

            case offsetPopper:
                HandleBuiltInOffsetPop(code, scope);
                return(true);

            case assertion:
                return(true);

            case protectCode:
                HandleBuiltInProtect(code, scope);
                return(true);

            case ThumbAssembly:
            case ARMAssembly:
                return(true);

            case ExternSymbol:
                CanCauseError err = scope.AddNewSymbol(code.Parameters[0].ToString(), new ValueExpression <int>(-1, new FilePosition()));

                if (err.CausedError)
                {
                    AddWarning((IExpression <int>)code, err.ErrorMessage);
                }
                return(true);

            case GlobalSymbol:
            case sectionMaker:
            case sectionEnd:
                return(true);

            default:
                return(false);
            }
        }
        private ScopeStructure <int> ExecuteLayoutPass <T>(IExpression <int> expression, ScopeStructure <int> scope, T output)
        {
            switch (expression.Type)
            {
            case EAExpressionType.Scope:
            {
                ScopeStructure <int> newScope = new ScopeStructure <int> (scope);
                scopeStructures [(Scope <int>)expression] = newScope;

                foreach (IExpression <int> child in expression.GetChildren())
                {
                    ExecuteLayoutPass(child, newScope, output);
                }

                break;
            }

            case EAExpressionType.Code:
            {
                Code <int> code = expression as Code <int>;

                if (code.IsEmpty || HandleBuiltInCodeLayout(code, scope))
                {
                    break;
                }

                if (code.CodeName.Name == "ASMC" && code.Parameters[0].ToString() != "" && !System.Text.RegularExpressions.Regex.IsMatch(code.Parameters[0].ToString(), @"\A\b(0[xX])?[0-9a-fA-F]+\b\Z"))
                {
                    scope.RegisterASMCLabel(code.Parameters[0].ToString());
                }

                Types.Type[] sig = ((IEnumerable <IExpression <int> >)code.Parameters).Select(new Func <IExpression <int>, Types.Type> (Types.Type.GetType <int>)).ToArray();

                CanCauseError <ICodeTemplate> templateError = this.storer.FindTemplate(code.CodeName.Name, sig);

                if (templateError.CausedError)
                {
                    AddError <int, ICodeTemplate> ((IExpression <int>)code, templateError);
                    break;
                }

                ICodeTemplate template = templateError.Result;

                // Checking alignment
                if (currentOffset % template.OffsetMod != 0)
                {
                    this.AddError <int> ((IExpression <int>)code, "Code {0}'s offset {1} is not divisible by {2}", (object)code.CodeName.Name, (object)this.currentOffset.ToHexString("$"), (object)template.OffsetMod);
                }

                // TODO: maybe we want to store the template somewhere to lookup for later?
                // May or may not be faster than computing it again in the write pass

                this.currentOffset += template.GetLengthBytes(((IEnumerable <IExpression <int> >)code.Parameters).ToArray());
                break;
            }

            case EAExpressionType.Labeled:
            {
                // record label names
                scope.SetLocalLabelAddress(((LabelExpression <int>)expression).LabelName, currentOffset);

                CanCauseError err = scope.AddNewSymbol(((LabelExpression <int>)expression).LabelName, new ValueExpression <int> (this.currentOffset, new FilePosition()));

                if (err.CausedError)
                {
                    AddWarning(expression, err.ErrorMessage);
                }

                break;
            }

            case EAExpressionType.Assignment:
            {
                Assignment <int>    assingment = (Assignment <int>)expression;
                CanCauseError <int> value      = Folding.Fold(assingment.Value, x => this.GetSymbolValue(scope, x));

                CanCauseError err = null;

                if (value.CausedError)
                {
                    err = scope.AddNewSymbol(assingment.Name, assingment.Value);
                }
                else
                {
                    err = scope.AddNewSymbol(assingment.Name, new ValueExpression <int> (value.Result, new FilePosition()));
                }

                if (err.CausedError)
                {
                    AddWarning(expression, err.ErrorMessage);
                }

                break;
            }

            case EAExpressionType.RawData:
            {
                RawData <int> rawData = (RawData <int>)expression;
                this.currentOffset += rawData.Data.Length;

                break;
            }

            default:
                throw new ArgumentException("Badly formed tree.");
            }

            // DeclareExternASMCLabels<T>(scope, output);
            return(scope);
        }