Lua-CSharp/src/Lua/Standard/Basic/AssertFunction.cs

namespace Lua.Standard.Basic;

public sealed class AssertFunction : LuaFunction
{
    public override string Name => "assert";
    public static readonly AssertFunction Instance = new();

    protected override ValueTask<int> InvokeAsyncCore(LuaFunctionExecutionContext context, Memory<LuaValue> buffer, CancellationToken cancellationToken)
    {
        var arg0 = context.ReadArgument(0);

        if (!arg0.ToBoolean())
        {
            var message = "assertion failed!";
            if (context.ArgumentCount >= 2)
            {
                message = context.ReadArgument<string>(1);
            }

            throw new LuaAssertionException(context.State.GetTraceback(), message);
        }

        return new(0);
    }
}