PorygonSharp/PorygonSharp/EvaluateResult.cs

using System;
using System.Runtime.InteropServices;
using PorygonSharp.EvalValues;

namespace PorygonSharp
{
    internal struct EvaluateResult : IDisposable
    {
        [StructLayout(LayoutKind.Sequential)]
        private struct EvaluateResultInternal
        {
            public readonly IntPtr Value;
            public readonly bool Result;
        }

        private readonly IntPtr _ptr;
        private readonly EvaluateResultInternal _internal;
        public EvaluateResult(IntPtr ptr)
        {
            _ptr = ptr;
            _internal = Marshal.PtrToStructure<EvaluateResultInternal>(ptr);
        }

        public EvalValue GetValue()
        {
            return new EvalValue(_internal.Value);
        }

        public bool IsSuccess()
        {
            return !_internal.Result;
        }

        public string GetError()
        {
            return GetErrorMessage(_ptr);
        }

        public void Dispose()
        {
            Marshal.FreeHGlobal(_ptr);
        }
        
        [DllImport("libPorygonLang", EntryPoint = "GetResultError", CallingConvention = CallingConvention.Cdecl)]
        private static extern string GetErrorMessage(IntPtr ptr);

    }
}