UnaryBooleanOperator.cs

using System;
using System.Threading.Tasks;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Objects;
 
namespace Waher.Script.Model
{
    public abstract class UnaryBooleanOperator : UnaryScalarOperator
    {
        public UnaryBooleanOperator(ScriptNode Operand, int Start, int Length, Expression Expression)
            : base(Operand, Start, Length, Expression)
        {
        }
 
        public override IElement Evaluate(Variables Variables)
        {
            IElement Op = this.op.Evaluate(Variables);
 
            if (Op.AssociatedObjectValue is bool BOp)
                return this.Evaluate(BOp);
            else
                return this.Evaluate(Op, Variables);
        }
 
        public override async Task<IElement> EvaluateAsync(Variables Variables)
        {
            if (!this.isAsync)
                return base.Evaluate(Variables);
 
            IElement Op = await this.op.EvaluateAsync(Variables);
 
            if (Op.AssociatedObjectValue is bool BOp)
                return await this.EvaluateAsync(BOp);
            else
                return await this.EvaluateAsync(Op, Variables);
        }
 
        public override IElement EvaluateScalar(IElement Operand, Variables Variables)
        {
            object Obj = Operand.AssociatedObjectValue;
 
            if (Obj is bool BOp)
                return this.Evaluate(BOp);
            else if (Expression.TryConvert(Obj, out bool b))
                return this.Evaluate(b);
            else
                throw new ScriptRuntimeException("Scalar operands must be boolean values.", this);
        }
 
        public override async Task<IElement> EvaluateScalarAsync(IElement Operand, Variables Variables)
        {
            object Obj = Operand.AssociatedObjectValue;
 
            if (Obj is bool BOp)
                return await this.EvaluateAsync(BOp);
            else if (Expression.TryConvert(Obj, out bool b))
                return await this.EvaluateAsync(b);
            else
                throw new ScriptRuntimeException("Scalar operands must be boolean values.", this);
        }
 
        public abstract IElement Evaluate(bool Operand);
 
        public virtual Task<IElement> EvaluateAsync(bool Operand)
        {
            return Task.FromResult<IElement>(this.Evaluate(Operand));
        }
 
    }
}