Do.cs

using System;
using System.Threading.Tasks;
using System.Xml;
using Waher.Content.Xml;
using Waher.Persistence.Attributes;
using Waher.Service.IoTBroker.StateMachines.Model.Attributes;
 
namespace Waher.Service.IoTBroker.StateMachines.Model.Actions.Conditional
{
    public class Do : ActionContainer
    {
        private ExpressionAttribute @while;
 
        public Do()
            : base()
        {
        }
 
        [DefaultValueNull]
        public string While
        {
            get => this.@while?.Expression;
            set => this.@while = new ExpressionAttribute(value, false, this);
        }
 
        public override string LocalName => nameof(Do);
 
        public override IStateMachineNode Create()
        {
            return new Do();
        }
 
        public override Task Parse(XmlElement Xml)
        {
            this.@while = new ExpressionAttribute(XML.Attribute(Xml, "while"), true, this);
 
            return base.Parse(Xml);
        }
 
        public override async Task Execute(EvaluationArguments Arguments)
        {
            while (true)
            {
                await base.Execute(Arguments);
            
                if (!(await this.@while.Evaluate(Arguments.Variables) is bool Result))
                    throw new Exception("Conditions must return boolean values.");
 
                if (!Result)
                    break;
            }
        }
    }
}