Created
April 13, 2024 17:32
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Golang generics sucks
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| package main | |
| import ( | |
| "fmt" | |
| "reflect" | |
| "slices" | |
| "strings" | |
| ) | |
| type Obj[K any, V comparable] struct { | |
| key K | |
| value V | |
| } | |
| func compareValues[T comparable](a, b T) int { | |
| var ( | |
| valueA = reflect.ValueOf(a) | |
| valueB = reflect.ValueOf(b) | |
| ) | |
| if valueA.Type() != valueB.Type() { | |
| panic("types are not comparable") | |
| } | |
| switch valueA.Kind() { | |
| case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: | |
| if valueA.Int() < valueB.Int() { | |
| return -1 | |
| } else if valueA.Int() > valueB.Int() { | |
| return 1 | |
| } else { | |
| return 0 | |
| } | |
| case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64: | |
| if valueA.Uint() < valueB.Uint() { | |
| return -1 | |
| } else if valueA.Uint() > valueB.Uint() { | |
| return 1 | |
| } else { | |
| return 0 | |
| } | |
| case reflect.Float32, reflect.Float64: | |
| if valueA.Float() < valueB.Float() { | |
| return -1 | |
| } else if valueA.Float() > valueB.Float() { | |
| return 1 | |
| } else { | |
| return 0 | |
| } | |
| case reflect.String: | |
| return strings.Compare(valueA.String(), valueB.String()) | |
| default: | |
| panic("unsupported type") | |
| } | |
| } | |
| func sortFunc[K, V comparable](obj1, obj2 Obj[K, V]) int { | |
| return compareValues(obj1.value, obj2.value) | |
| } | |
| type ObjArr[K comparable, V comparable] []Obj[K, V] | |
| func (a ObjArr[K, V]) Sort() { | |
| slices.SortFunc(a, sortFunc) | |
| } | |
| func mapToSlice[K, V comparable](m map[K]V) ObjArr[K, V] { | |
| var slice []Obj[K, V] | |
| for k, v := range m { | |
| slice = append(slice, Obj[K, V]{ | |
| key: k, | |
| value: v, | |
| }) | |
| } | |
| return slice | |
| } | |
| func sliceToMap[K, V comparable](s ObjArr[K, V]) map[K]V { | |
| var m = make(map[K]V) | |
| for _, v := range s { | |
| m[v.key] = v.value | |
| } | |
| return m | |
| } | |
| func main() { | |
| var m = map[string]int{ | |
| "second": 2, | |
| "forth": 4, | |
| "first": 1, | |
| "third": 3, | |
| "fifth": 5, | |
| } | |
| var s = mapToSlice(m) | |
| fmt.Println(s) // [{second 2} {forth 4} {first 1} {third 3} {fifth 5}] | |
| s.Sort() | |
| fmt.Println(s) // [{first 1} {second 2} {third 3} {forth 4} {fifth 5}] | |
| var m2 = map[string]string{ | |
| "second": "b", | |
| "forth": "d", | |
| "first": "a", | |
| "third": "c", | |
| "fifth": "e", | |
| } | |
| var s2 = mapToSlice(m2) | |
| fmt.Println(s2) // [{second b} {forth d} {first a} {third c} {fifth e}] | |
| s2.Sort() | |
| fmt.Println(s2) // [{first a} {second b} {third c} {forth d} {fifth e}] | |
| } |
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