Boo.Lang.Compiler.Steps.EmitAssembly.OnExpressionInterpolationExpression C# (CSharp) Метод

        public override void OnExpressionInterpolationExpression(ExpressionInterpolationExpression node)
        {
            Type stringBuilderType = typeof(StringBuilder);
            ConstructorInfo constructor = stringBuilderType.GetConstructor(Type.EmptyTypes);
            ConstructorInfo constructorString = stringBuilderType.GetConstructor(new Type[] { typeof(string) });

            MethodInfo appendObject = Methods.InstanceFunctionOf<StringBuilder, object, StringBuilder>(sb => sb.Append);
            MethodInfo appendString = Methods.InstanceFunctionOf<StringBuilder, string, StringBuilder>(sb => sb.Append);
            Expression arg0 = node.Expressions[0];
            IType argType = arg0.ExpressionType;

            /* if arg0 is a string, let's call StringBuilder constructor
             * directly with the string */
            if ( ( typeof(StringLiteralExpression) == arg0.GetType()
                   && ((StringLiteralExpression) arg0).Value.Length > 0 )
                || ( typeof(StringLiteralExpression) != arg0.GetType()
                     && TypeSystemServices.StringType == argType ) )
            {
                Visit(arg0);
                PopType();
                _il.Emit(OpCodes.Newobj, constructorString);
            }
            else
            {
                _il.Emit(OpCodes.Newobj, constructor);
                arg0 = null; /* arg0 is not a string so we want it to be appended below */
            }

            string formatString;
            foreach (Expression arg in node.Expressions)
            {
                /* we do not need to append literal string.Empty
                 * or arg0 if it has been handled by ctor */
                if ( ( typeof(StringLiteralExpression) == arg.GetType()
                       && ((StringLiteralExpression) arg).Value.Length == 0 )
                    || arg == arg0 )
                {
                    continue;
                }

                formatString = arg["formatString"] as string; //annotation
                if (!string.IsNullOrEmpty(formatString))
                    _il.Emit(OpCodes.Ldstr, string.Format("{{0:{0}}}", formatString));

                Visit(arg);
                argType = PopType();

                if (!string.IsNullOrEmpty(formatString))
                {
                    EmitCastIfNeeded(TypeSystemServices.ObjectType, argType);
                    Call(StringFormat);
                }

                if (TypeSystemServices.StringType == argType || !string.IsNullOrEmpty(formatString))
                {
                    Call(appendString);
                }
                else
                {
                    EmitCastIfNeeded(TypeSystemServices.ObjectType, argType);
                    Call(appendObject);
                }
            }
            Call(stringBuilderType.GetMethod("ToString", Type.EmptyTypes));
            PushType(TypeSystemServices.StringType);
        }