I just started diving into Go recently and I have one major point of confusion: I am struggling to understand when exactly it is necessary to dereference a pointer explicitly.
For example I know that the .
operator will handle dereferencing a pointer
ptr := new(SomeStruct)
ptr.Field = "foo" //Automatically dereferences
In what other scenarios does go do this? It seems to for example, with arrays.
ptr := new([5][5]int)
ptr[0][0] = 1
I have been unable to find this in the spec, the section for pointers is very short and doesn't even touch dereferencing. Any clarification of the rules for dereferencing go's pointers would be great!
The selector expression (e.g. x.f
) does that:
Selectors automatically dereference pointers to structs. If
x
is a pointer to a struct,x.y
is shorthand for(*x).y
; if the fieldy
is also a pointer to a struct,x.y.z
is shorthand for(*(*x).y).z
, and so on. Ifx
contains an anonymous field of type*A
, whereA
is also a struct type,x.f
is a shortcut for(*x.A).f
.
The definition of the indexing operation specifies that an array pointer may be indexed:
For a of type
A
or*A
whereA
is an array type, or for a of typeS
whereS
is a slice type