generics

Author: tbhaxor

generics/go.mod

@@ -0,0 +1,3 @@
+module generics
+
+go 1.20

generics/main.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+"bytes"
+"encoding/json"
+"fmt"
+)
+
+type Person struct {
+Name string `json:"name"`
+Age uint `json:"age"`
+}
+
+type Employee struct {
+Person
+Company string `json:"company"`
+}
+
+// parseJson can accept body of type string but can return pointer to "any" type data
+// because of T used as generics here
+func parseJson[T any](body string) *T {
+s := new(T)
+
+decoder := json.NewDecoder(bytes.NewBufferString(body))
+
+if err := decoder.Decode(s); err != nil {
+panic(err)
+} else {
+return s
+}
+}
+
+const (
+jsonString = `{"name": "Gurkirat Singh", "age": 21, "company": "Turing"}`
+)
+
+func main() {
+// type specified in the [ and ] will be replaced as the type in the function
+// on hover you will see it returns *Person
+person := parseJson[Person](jsonString)
+
+// here, on hover you will see it returns *Employee
+employee := parseJson[Employee](jsonString)
+
+fmt.Printf("%+v\n", person)
+fmt.Printf("%+v\n", employee)
+
+}

go.work

@@ -4,6 +4,7 @@ use (
 ./datatypes
 ./deferfunc
 ./funcname
+./generics
 ./helloworld
 ./panic
 ./polymorphism