neo-go/pkg/interop/enumerator/enumerator.go

/*
Package enumerator provides functions to work with enumerators.
*/
package enumerator

// Enumerator represents NEO enumerator type, it's an opaque data structure
// that can be used with functions from this package. It's similar to more
// widely used Iterator (see `iterator` package), but ranging over arrays
// or structures that have values with no explicit keys.
type Enumerator struct{}

// Create creates a new enumerator from the given items (slice or structure).
// New enumerator points at index -1 of its items, so the user of it has to
// advance it first with Next. This function uses `System.Enumerator.Create`
// syscall.
func Create(items []interface{}) Enumerator {
	return Enumerator{}
}

// Next moves position of the given enumerator by one and returns a bool that
// tells whether there is a new value present in this new position. If it is,
// you can use Value to get it, if not then there are no more values in this
// enumerator. This function uses `System.Enumerator.Next` syscall.
func Next(e Enumerator) bool {
	return true
}

// Value returns current enumerator's item value, it's only valid to call it
// after Next returning true. This function uses `System.Enumerator.Value` syscall.
func Value(e Enumerator) interface{} {
	return nil
}

// Concat concatenates two given enumerators returning one that will range on
// a first and then continue with b. Enumerator positions are not reset for a
// and b, so if any of them was already advanced by Next the resulting
// Enumerator will point at this new position and never go back to previous
// values. This function uses `System.Enumerator.Concat` syscall.
func Concat(a, b Enumerator) Enumerator {
	return Enumerator{}
}