CODEWITHSUNDEEP
go
Raghu
Raghu

Reputation: 722

Is it possible to alias nil in Golang

While organizing my projects, I observe nil comparisons in many places. I wish to replace nil with NULL or Null. I respect Golang specs, but I am curious if we can do this.

I already did it for interface{} , context.Context as follows.

type CON = context.Context 
type Any = interface{}

Upvotes: 0

Views: 396

Answers (1)

Hymns For Disco
Hymns For Disco

Reputation: 8395

You cannot. What you show there are type aliases. nil is not a type. It is a value of a wide range of different types. You may hope that you can make a constant with a value of nil, similar to how you can make a constant of value 0, but this is explicitly disallowed by the compiler:

const NULL = nil

Error: const initializer cannot be nil

According to the language specification:

There are boolean constants, rune constants, integer constants, floating-point constants, complex constants, and string constants.

None of these types can have a nil value, therefore a nil constant is not possible.

You might also try to make a variable which holds the value nil, but you'll find the problem that it doesn't work if you don't declare the type of the variable:

var NULL = nil

Error: use of untyped nil

You can make it legal by adding a nilable type to the variable, but then it will no longer be very useful as it will only be comparable to that specific type.

Upvotes: 4

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