package either import ( F "github.com/ibm/fp-go/function" ) // constructs a function that creates a resource, then operates on it and then releases the resource func WithResource[E, R, A any](onCreate func() Either[E, R], onRelease func(R) Either[E, any]) func(func(R) Either[E, A]) Either[E, A] { return func(f func(R) Either[E, A]) Either[E, A] { return MonadChain( onCreate(), func(r R) Either[E, A] { // run the code and make sure to release as quickly as possible res := f(r) released := onRelease(r) // handle the errors return fold( res, Left[E, A], func(a A) Either[E, A] { return F.Pipe1( released, MapTo[E, any](a), ) }) }, ) } }