/// <summary>
/// Create a new cancellation context and run the provided Aff in that context
/// </summary>
/// <param name="ma">Operation to run in the next context</param>
/// <typeparam name="RT">Runtime environment</typeparam>
/// <typeparam name="A">Bound value type</typeparam>
/// <returns>An asynchronous effect that captures the operation running in context</returns>
public static Aff <RT, A> localCancel <RT, A>(Aff <RT, A> ma) where RT : struct, HasCancel <RT> =>
AffMaybe <RT, A>(async rt =>
{
var rt1 = rt.LocalCancel;
using (rt1.CancellationTokenSource)
{
return(await ma.ReRun(rt1).ConfigureAwait(false));
}
});
/// <summary>
/// Safely use a disposable resource
/// </summary>
/// <param name="Acq">Acquire resource</param>
/// <param name="Use">Use resource</param>
public static Aff <R> use <H, R>(Aff <H> Acq, Func <H, Eff <R> > Use) where H : IDisposable =>
AffMaybe(async() =>
{
var h = await Acq.ReRun().ConfigureAwait(false);
if (h.IsFail)
{
return(h.Cast <R>());
}
try
{
return(Use(h.Value).Run());
}
finally
{
h.Value?.Dispose();
}
});
/// <summary>
/// Safely use a disposable resource
/// </summary>
/// <param name="Acq">Acquire resource</param>
/// <param name="Use">Use resource</param>
public static Aff <RT, R> use <RT, H, R>(Aff <H> Acq, Func <H, Eff <RT, R> > Use)
where RT : struct, HasCancel <RT>
where H : IDisposable =>
AffMaybe <RT, R>(async env =>
{
var h = await Acq.ReRun().ConfigureAwait(false);
if (h.IsFail)
{
return(h.Cast <R>());
}
try
{
return(Use(h.Value).Run(env));
}
finally
{
h.Value?.Dispose();
}
});
