func ExampleMap() {
const source = `package P
var X []string
var Y []string
const p, q = 1.0, 2.0
func f(offset int32) (value byte, ok bool)
func g(rune) (uint8, bool)
`
// Parse and type-check the package.
fset := token.NewFileSet()
f, err := parser.ParseFile(fset, "P.go", source, 0)
if err != nil {
panic(err)
}
pkg, err := new(types.Config).Check("P", fset, []*ast.File{f}, nil)
if err != nil {
panic(err)
}
scope := pkg.Scope()
// Group names of package-level objects by their type.
var namesByType typeutil.Map // value is []string
for _, name := range scope.Names() {
T := scope.Lookup(name).Type()
names, _ := namesByType.At(T).([]string)
names = append(names, name)
namesByType.Set(T, names)
}
// Format, sort, and print the map entries.
var lines []string
namesByType.Iterate(func(T types.Type, names interface{}) {
lines = append(lines, fmt.Sprintf("%s %s", names, T))
})
sort.Strings(lines)
for _, line := range lines {
fmt.Println(line)
}
// Output:
// [X Y] []string
// [f g] func(offset int32) (value byte, ok bool)
// [p q] untyped float
}
