func ExampleMakeReduce_Second() {
// Let's make a reduce function
var reduce func([]string, func(result string, s string, i int) string, string) string
if err := funcs.MakeReduce(&reduce); err != nil {
log.Fatal(err)
}
strings := []string{"foo", "bar"}
fmt.Println(reduce(strings, func(result, element string, index int) string {
return result + fmt.Sprint(index) + element
}, ""))
// Output:
// 0foo1bar
}
func ExampleMakeReduce() {
// Let's use MakeReduce to create a map function.
type Person struct {
Name string
Age int
}
var MapPersonsToNames func(persons []Person, reducer func(names []string, person Person) []string, initial []string) []string
err := funcs.MakeReduce(&MapPersonsToNames)
if err != nil {
log.Fatal(err)
}
result := MapPersonsToNames([]Person{{"Frank", 30}, {"John", 43}, {"Jane", 26}}, func(names []string, person Person) []string {
return append(names, person.Name)
}, []string{})
fmt.Println(result)
// Output:
// [Frank John Jane]
}
func TestErrInvalidNumberOfInputValues(t *testing.T) {
var reduce func(collection []string, reducer func(result string, element string) string)
err := funcs.MakeReduce(&reduce)
test.Fatal(t, err, funcs.ErrInvalidNumberOfInputValues)
}
func TestErrNotAFunction(t *testing.T) {
var reduce interface{}
err := funcs.MakeReduce(&reduce)
test.Fatal(t, err, funcs.ErrNotAFunction)
}
func TestErrNotApointer(t *testing.T) {
var reduce func([]int, func(int, int) int, int)
err := funcs.MakeReduce(reduce)
test.Fatal(t, err, funcs.ErrNotAPointer)
}