add a new x/reflex sub-package for reflection common functions - may be improved in the near future

x/reflex/zero.go

@@ -0,0 +1,65 @@
+package reflex
+
+import (
+	"encoding/json"
+	"net"
+)
+
+// Zeroer can be implemented by custom types
+// to report whether its current value is zero.
+// Standard Time also implements that.
+type Zeroer interface {
+	IsZero() bool
+}
+
+// IsZero reports whether "v" is zero value or no.
+// The given "v" value can complete the Zeroer interface
+// which can be used to customize the behavior for each type of "v".
+func IsZero(v interface{}) bool {
+	switch t := v.(type) {
+	case Zeroer: // completes the time.Time as well.
+		return t.IsZero()
+	case string:
+		return t == ""
+	case int:
+		return t == 0
+	case int8:
+		return t == 0
+	case int16:
+		return t == 0
+	case int32:
+		return t == 0
+	case int64:
+		return t == 0
+	case uint:
+		return t == 0
+	case uint8:
+		return t == 0
+	case uint16:
+		return t == 0
+	case uint32:
+		return t == 0
+	case uint64:
+		return t == 0
+	case float32:
+		return t == 0
+	case float64:
+		return t == 0
+	case bool:
+		return !t
+	case []int:
+		return len(t) == 0
+	case []string:
+		return len(t) == 0
+	case [][]int:
+		return len(t) == 0
+	case [][]string:
+		return len(t) == 0
+	case json.Number:
+		return t.String() == ""
+	case net.IP:
+		return len(t) == 0
+	default:
+		return false
+	}
+}