FunctionOneVariable.cs

using System.Threading.Tasks;
using Waher.Script.Abstraction.Elements;
 
namespace Waher.Script.Model
{
    public abstract class FunctionOneVariable : Function
    {
        private ScriptNode argument;
        private bool isAsync;
 
        public FunctionOneVariable(ScriptNode Argument, int Start, int Length, Expression Expression)
            : base(Start, Length, Expression)
        {
            this.argument = Argument;
            this.argument?.SetParent(this);
 
            this.isAsync = Argument?.IsAsynchronous ?? false;
        }
 
        public ScriptNode Argument => this.argument;
 
        public override string[] DefaultArgumentNames => new string[] { "x" };
 
        public override bool IsAsynchronous => this.isAsync;
 
        public override IElement Evaluate(Variables Variables)
        {
            IElement Arg = this.argument.Evaluate(Variables);
            return this.Evaluate(Arg, Variables);
        }
 
        public override async Task<IElement> EvaluateAsync(Variables Variables)
        {
            if (!this.IsAsynchronous)
                return this.Evaluate(Variables);
 
            IElement Arg = await this.argument.EvaluateAsync(Variables);
            return await this.EvaluateAsync(Arg, Variables);
        }
 
        public abstract IElement Evaluate(IElement Argument, Variables Variables);
 
        public virtual Task<IElement> EvaluateAsync(IElement Argument, Variables Variables)
        {
            return Task.FromResult(this.Evaluate(Argument, Variables));
        }
 
        public override bool ForAllChildNodes(ScriptNodeEventHandler Callback, object State, SearchMethod Order)
        {
            if (Order == SearchMethod.DepthFirst)
            {
                if (!(this.argument?.ForAllChildNodes(Callback, State, Order) ?? true))
                    return false;
            }
 
            if (!(this.argument is null))
            {
                bool b = !Callback(this.argument, out ScriptNode NewNode, State);
                if (!(NewNode is null))
                {
                    this.argument = NewNode;
                    this.argument.SetParent(this);
                    
                    this.isAsync = NewNode.IsAsynchronous;
                }
 
                if (b || (Order == SearchMethod.TreeOrder && !this.argument.ForAllChildNodes(Callback, State, Order)))
                    return false;
            }
 
            if (Order == SearchMethod.BreadthFirst)
            {
                if (!(this.argument?.ForAllChildNodes(Callback, State, Order) ?? true))
                    return false;
            }
 
            return true;
        }
 
        public override bool Equals(object obj)
        {
            return obj is FunctionOneVariable O &&
                this.argument.Equals(O.argument) &&
                base.Equals(obj);
        }
 
        public override int GetHashCode()
        {
            int Result = base.GetHashCode();
            Result ^= Result << 5 ^ this.argument.GetHashCode();
            return Result;
        }
 
    }
}