go/src/sort/example_keys_test.go

type earthMass …

type au …

type Planet …

type By …

// Sort is a method on the function type, By, that sorts the argument slice according to the function.
func (by By) Sort(planets []Planet) { … }

type planetSorter …

// Len is part of sort.Interface.
func (s *planetSorter) Len() int { … }

// Swap is part of sort.Interface.
func (s *planetSorter) Swap(i, j int) { … }

// Less is part of sort.Interface. It is implemented by calling the "by" closure in the sorter.
func (s *planetSorter) Less(i, j int) bool { … }

var planets …

// ExampleSortKeys demonstrates a technique for sorting a struct type using programmable sort criteria.
func Example_sortKeys() { … }