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 }
func TestMap(t *testing.T) { var tmap *typeutil.Map // All methods but Set are safe on on (*T)(nil). tmap.Len() tmap.At(tPStr1) tmap.Delete(tPStr1) tmap.KeysString() tmap.String() tmap = new(typeutil.Map) // Length of empty map. if l := tmap.Len(); l != 0 { t.Errorf("Len() on empty Map: got %d, want 0", l) } // At of missing key. if v := tmap.At(tPStr1); v != nil { t.Errorf("At() on empty Map: got %v, want nil", v) } // Deletion of missing key. if tmap.Delete(tPStr1) { t.Errorf("Delete() on empty Map: got true, want false") } // Set of new key. if prev := tmap.Set(tPStr1, "*string"); prev != nil { t.Errorf("Set() on empty Map returned non-nil previous value %s", prev) } // Now: {*string: "*string"} // Length of non-empty map. if l := tmap.Len(); l != 1 { t.Errorf("Len(): got %d, want 1", l) } // At via insertion key. if v := tmap.At(tPStr1); v != "*string" { t.Errorf("At(): got %q, want \"*string\"", v) } // At via equal key. if v := tmap.At(tPStr2); v != "*string" { t.Errorf("At(): got %q, want \"*string\"", v) } // Iteration over sole entry. tmap.Iterate(func(key types.Type, value interface{}) { if key != tPStr1 { t.Errorf("Iterate: key: got %s, want %s", key, tPStr1) } if want := "*string"; value != want { t.Errorf("Iterate: value: got %s, want %s", value, want) } }) // Setion with key equal to present one. if prev := tmap.Set(tPStr2, "*string again"); prev != "*string" { t.Errorf("Set() previous value: got %s, want \"*string\"", prev) } // Setion of another association. if prev := tmap.Set(tChanInt1, "<-chan int"); prev != nil { t.Errorf("Set() previous value: got %s, want nil", prev) } // Now: {*string: "*string again", <-chan int: "<-chan int"} want1 := "{*string: \"*string again\", <-chan int: \"<-chan int\"}" want2 := "{<-chan int: \"<-chan int\", *string: \"*string again\"}" if s := tmap.String(); s != want1 && s != want2 { t.Errorf("String(): got %s, want %s", s, want1) } want1 = "{*string, <-chan int}" want2 = "{<-chan int, *string}" if s := tmap.KeysString(); s != want1 && s != want2 { t.Errorf("KeysString(): got %s, want %s", s, want1) } // Keys(). I := types.Identical switch k := tmap.Keys(); { case I(k[0], tChanInt1) && I(k[1], tPStr1): // ok case I(k[1], tChanInt1) && I(k[0], tPStr1): // ok default: t.Errorf("Keys(): got %v, want %s", k, want2) } if l := tmap.Len(); l != 2 { t.Errorf("Len(): got %d, want 1", l) } // At via original key. if v := tmap.At(tPStr1); v != "*string again" { t.Errorf("At(): got %q, want \"*string again\"", v) } hamming := 1 tmap.Iterate(func(key types.Type, value interface{}) { switch { case I(key, tChanInt1): hamming *= 2 // ok case I(key, tPStr1): hamming *= 3 // ok } }) if hamming != 6 { t.Errorf("Iterate: hamming: got %d, want %d", hamming, 6) } if v := tmap.At(tChanInt2); v != "<-chan int" { t.Errorf("At(): got %q, want \"<-chan int\"", v) } // Deletion with key equal to present one. if !tmap.Delete(tChanInt2) { t.Errorf("Delete() of existing key: got false, want true") } // Now: {*string: "*string again"} if l := tmap.Len(); l != 1 { t.Errorf("Len(): got %d, want 1", l) } // Deletion again. if !tmap.Delete(tPStr2) { t.Errorf("Delete() of existing key: got false, want true") } // Now: {} if l := tmap.Len(); l != 0 { t.Errorf("Len(): got %d, want %d", l, 0) } if s := tmap.String(); s != "{}" { t.Errorf("Len(): got %q, want %q", s, "") } }