FtsFile.cs

using System.Threading.Tasks;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Model;
using Waher.Script.Objects;
 
namespace Waher.Script.FullTextSearch.Functions
{
    public class FtsFile : FunctionMultiVariate
    {
        public FtsFile(ScriptNode IndexCollection, ScriptNode FileName,
            int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { IndexCollection, FileName }, argumentTypes2Scalar,
                  Start, Length, Expression)
        {
        }
 
        public override string FunctionName => nameof(FtsFile);
 
        public override string[] DefaultArgumentNames => new string[] { "IndexCollection", "FileName" };
 
        public override bool IsAsynchronous => true;
 
        public override IElement Evaluate(IElement[] Arguments, Variables Variables)
        {
            return this.EvaluateAsync(Arguments, Variables).Result;
        }
 
        public override async Task<IElement> EvaluateAsync(IElement[] Arguments, Variables Variables)
        {
            int i = 0;
            string Index = ToString(Arguments[i++]) ?? string.Empty;
            string FileName = ToString(Arguments[i++]) ?? string.Empty;
 
            if (string.IsNullOrEmpty(FileName))
                throw new ScriptRuntimeException("Empty filename.", this);
 
            bool Result = await Waher.Persistence.FullTextSearch.Search.IndexFile(Index, FileName);
 
            return Result ? BooleanValue.True : BooleanValue.False;
        }
    }
}