v0.0.367

goextVersion.go

@@ -1,5 +1,5 @@
 package goext
 
-const GoextVersion = "0.0.366"
+const GoextVersion = "0.0.367"
 
-const GoextVersionTimestamp = "2024-01-12T15:10:48+0100"
+const GoextVersionTimestamp = "2024-01-12T18:40:29+0100"

reflectext/mapAccess.go

@@ -0,0 +1,98 @@
+package reflectext
+
+import (
+	"reflect"
+	"strings"
+)
+
+// GetMapPath returns the value deep inside a hierahically nested map structure
+// eg:
+// x := langext.H{"K1": langext.H{"K2": 665}}
+// GetMapPath[int](x, "K1.K2") == 665
+func GetMapPath[TData any](mapval any, path string) (TData, bool) {
+	var ok bool
+
+	split := strings.Split(path, ".")
+
+	for i, key := range split {
+
+		if i < len(split)-1 {
+			mapval, ok = GetMapField[any](mapval, key)
+			if !ok {
+				return *new(TData), false
+			}
+		} else {
+			return GetMapField[TData](mapval, key)
+		}
+	}
+
+	return *new(TData), false
+}
+
+// GetMapField gets the value of a map, without knowing the actual types (mapval is any)
+// eg:
+// x := langext.H{"K1": 665}
+// GetMapPath[int](x, "K1") == 665
+//
+// works with aliased types and autom. dereferences pointes
+func GetMapField[TData any, TKey comparable](mapval any, key TKey) (TData, bool) {
+
+	rval := reflect.ValueOf(mapval)
+
+	for rval.Kind() == reflect.Ptr && !rval.IsNil() {
+		rval = rval.Elem()
+	}
+
+	if rval.Kind() != reflect.Map {
+		return *new(TData), false // mapval is not a map
+	}
+
+	kval := reflect.ValueOf(key)
+
+	if !kval.Type().AssignableTo(rval.Type().Key()) {
+		return *new(TData), false // key cannot index mapval
+	}
+
+	eval := rval.MapIndex(kval)
+	if !eval.IsValid() {
+		return *new(TData), false // key does not exist in mapval
+	}
+
+	destType := reflect.TypeOf(new(TData)).Elem()
+
+	if eval.Type() == destType {
+		return eval.Interface().(TData), true
+	}
+
+	if eval.CanConvert(destType) && !preventConvert(eval.Type(), destType) {
+		return eval.Convert(destType).Interface().(TData), true
+	}
+
+	if (eval.Kind() == reflect.Ptr || eval.Kind() == reflect.Interface) && eval.IsNil() && destType.Kind() == reflect.Ptr {
+		return *new(TData), false // special case: mapval[key] is nil
+	}
+
+	for (eval.Kind() == reflect.Ptr || eval.Kind() == reflect.Interface) && !eval.IsNil() {
+		eval = eval.Elem()
+
+		if eval.Type() == destType {
+			return eval.Interface().(TData), true
+		}
+
+		if eval.CanConvert(destType) && !preventConvert(eval.Type(), destType) {
+			return eval.Convert(destType).Interface().(TData), true
+		}
+	}
+
+	return *new(TData), false // mapval[key] is not of type TData
+}
+
+func preventConvert(t1 reflect.Type, t2 reflect.Type) bool {
+	if t1.Kind() == reflect.String && t1.Kind() != reflect.String {
+		return true
+	}
+	if t2.Kind() == reflect.String && t1.Kind() != reflect.String {
+		return true
+	}
+	return false
+}

reflectext/mapAccess_test.go

@@ -0,0 +1,55 @@
+package reflectext
+
+import (
+	"fmt"
+	"gogs.mikescher.com/BlackForestBytes/goext/tst"
+	"testing"
+)
+
+func TestGetMapPath(t *testing.T) {
+	type PseudoInt = int64
+
+	mymap2 := map[string]map[string]any{"Test": {"Second": 3}}
+
+	var maany2 any = mymap2
+
+	tst.AssertEqual(t, fmt.Sprint(GetMapPath[int](maany2, "Test.Second")), "3 true")
+	tst.AssertEqual(t, fmt.Sprint(GetMapPath[int](maany2, "Test2.Second")), "0 false")
+	tst.AssertEqual(t, fmt.Sprint(GetMapPath[int](maany2, "Test.Second2")), "0 false")
+	tst.AssertEqual(t, fmt.Sprint(GetMapPath[string](maany2, "Test.Second")), "false")
+	tst.AssertEqual(t, fmt.Sprint(GetMapPath[string](maany2, "Test2.Second")), "false")
+	tst.AssertEqual(t, fmt.Sprint(GetMapPath[string](maany2, "Test.Second2")), "false")
+	tst.AssertEqual(t, fmt.Sprint(GetMapPath[PseudoInt](maany2, "Test.Second")), "3 true")
+	tst.AssertEqual(t, fmt.Sprint(GetMapPath[PseudoInt](maany2, "Test2.Second")), "0 false")
+	tst.AssertEqual(t, fmt.Sprint(GetMapPath[PseudoInt](maany2, "Test.Second2")), "0 false")
+}
+
+func TestGetMapField(t *testing.T) {
+	type PseudoInt = int64
+
+	mymap1 := map[string]any{"Test": 12}
+	mymap2 := map[string]int{"Test": 12}
+
+	var maany1 any = mymap1
+	var maany2 any = mymap2
+
+	tst.AssertEqual(t, fmt.Sprint(GetMapField[int](maany1, "Test")), "12 true")
+	tst.AssertEqual(t, fmt.Sprint(GetMapField[int](maany1, "Test2")), "0 false")
+	tst.AssertEqual(t, fmt.Sprint(GetMapField[string](maany1, "Test")), "false")
+	tst.AssertEqual(t, fmt.Sprint(GetMapField[string](maany1, "Test2")), "false")
+	tst.AssertEqual(t, fmt.Sprint(GetMapField[PseudoInt](maany1, "Test")), "12 true")
+	tst.AssertEqual(t, fmt.Sprint(GetMapField[PseudoInt](maany1, "Test2")), "0 false")
+
+	tst.AssertEqual(t, fmt.Sprint(GetMapField[int](maany2, "Test")), "12 true")
+	tst.AssertEqual(t, fmt.Sprint(GetMapField[int](maany2, "Test2")), "0 false")
+	tst.AssertEqual(t, fmt.Sprint(GetMapField[string](maany2, "Test")), "false")
+	tst.AssertEqual(t, fmt.Sprint(GetMapField[string](maany2, "Test2")), "false")
+	tst.AssertEqual(t, fmt.Sprint(GetMapField[PseudoInt](maany2, "Test")), "12 true")
+	tst.AssertEqual(t, fmt.Sprint(GetMapField[PseudoInt](maany2, "Test2")), "0 false")
+}
+
+func main2() {
+}
+
+func main() {
+}