I have the following struct which contains a net/http.Request:
type MyRequest struct { http.Request PathParams map[string]string } Now I want to initialize the anonymous inner struct http.Request in the following function:
func New(origRequest *http.Request, pathParams map[string]string) *MyRequest { req := new(MyRequest) req.PathParams = pathParams return req } How can I initialize the inner struct with the parameter origRequest?
req := new(MyRequest) req.PathParams = pathParams req.Request = origRequest or...
req := &MyRequest{ PathParams: pathParams Request: origRequest } See: http://golang.org/ref/spec#Struct_types for more about embedding and how the fields get named.
cannot use origRequest (type *http.Request) as type http.Request in assignment. I guess this is because Request is not a named field.
http.Request ends up being called just Request.What about:
func New(origRequest *http.Request, pathParams map[string]string) *MyRequest { return &MyRequest{*origRequest, pathParams} } It shows that instead of
New(foo, bar) you might prefer just
&MyRequest{*foo, bar} directly.
var hits struct { sync.Mutex n int } hits.Lock() hits.n++ hits.Unlock() (from 10 things you probably didn't know about Go)As Jeremy shows above, the "name" of an anonymous field is the same as the type of the field. So if the value of x were a struct containing an anonymous int, then x.int would refer to that field.
Just for completeness sake, I'll add another example as well. Based on the comment from @Victor
This example shows another way recommended https://play.golang.org/p/Gbn8e6CTVi_c
type MyRequest struct { http.Request PathParams map[string]string } func New(origRequest *http.Request, pathParams map[string]string) *MyRequest { req := MyRequest{Request: origRequest, PathParams: pathParams} return req } Another comment from @Jeffery Martinez helped clarify it further:
As for how the fields get named: "The unqualified type name acts as the field name." So
http.Requestends up being called justRequest
i.e: The two following declarations are equivalent
// Version 1 type MyRequest struct { http.Request PathParams map[string]string } // Version 2 type MyRequest struct { Request http.Request PathParams map[string]string } 