示例#1
0
        private async Task <DynValue> ExecuteStatementList(List <AstNode> statements, CancellationToken token)
        {
            var retVal = DynValue.Zero;

            if (BreakExecution)
            {
                BreakExecution = false;
                throw new ScriptTerminationException("Execution stopped by user.");
            }

            foreach (var statement in statements)
            {
                do
                {
                    token.ThrowIfCancellationRequested();
                } while (SuspendExecution);

                if (BreakExecution)
                {
                    BreakExecution = false;
                    throw new ScriptTerminationException("Execution stopped by user.");
                }

                if (LoopStack.Count > 0)
                {
                    var loopStackTop = LoopStack.Peek();

                    if (loopStackTop.BreakLoop || loopStackTop.SkipThisIteration)
                    {
                        break;
                    }
                }

                if (CallStack.Count > 0)
                {
                    var callStackTop = CallStack.Peek();

                    if (callStackTop.ReturnNow)
                    {
                        retVal = callStackTop.ReturnValue;
                        break;
                    }
                }

                retVal = Visit(statement);
            }

            return(retVal);
        }
        public override DynValue Visit(ForLoopNode forLoopNode)
        {
            _ = Visit(forLoopNode.Assignment).Number;

            DynValue step = new DynValue(1);

            var targetValue = Visit(forLoopNode.TargetValue);

            if (forLoopNode.Step != null)
            {
                step = Visit(forLoopNode.Step);
            }

            var isLocalScope = false;

            var assignmentNode = (forLoopNode.Assignment as AssignmentNode);
            var iteratorName   = assignmentNode.Variable.Name;

            if (assignmentNode.LocalScope)
            {
                isLocalScope = true;
            }

            try
            {
                LoopStack.Push(new LoopStackItem());
                while (true)
                {
                    ExecuteStatementList(forLoopNode.StatementList).GetAwaiter().GetResult();

                    double iterator;
                    if (isLocalScope)
                    {
                        var callStackTop = CallStack.Peek();
                        iterator = callStackTop.LocalVariableScope[iteratorName].Number;
                    }
                    else
                    {
                        iterator = Environment.Globals[iteratorName].Number;
                    }

                    if (step.Number < 0)
                    {
                        if (iterator < targetValue.Number)
                        {
                            break;
                        }
                        else
                        {
                            iterator -= step.Number;
                        }
                    }
                    else
                    {
                        if (iterator >= targetValue.Number)
                        {
                            break;
                        }
                        else
                        {
                            iterator += step.Number;
                        }
                    }

                    if (isLocalScope)
                    {
                        // no throw on localvar token, so
                        // guaranteed we're inside a function

                        var callStackTop = CallStack.Peek();
                        callStackTop.LocalVariableScope[iteratorName] = new DynValue(iterator);
                    }
                    else
                    {
                        Environment.Globals[iteratorName] = new DynValue(iterator);
                    }

                    var loopStackTop = LoopStack.Peek();

                    if (loopStackTop.BreakLoop)
                    {
                        break;
                    }

                    if (loopStackTop.SkipThisIteration)
                    {
                        loopStackTop.SkipThisIteration = false;
                        continue;
                    }
                }
            }
            catch
            {
                throw;
            }
            finally
            {
                LoopStack.Pop();
            }

            return(DynValue.Zero);
        }