Go idiomatic way to name boolean predicate functions

Question

Lets say you are working with a func that returns a bool as to whether a user has been active in the last month. In Ruby: ``` def active_in_last_month?;end ``` In C# ``` public bool WasActiveInLastMonth(){} ``` What is the idiomatic way of naming boolean predicate functions in Go?

Accepted Answer

tl;dr

```
func wasActiveInLastMonth() bool
```

Full Answer

I looked in the GitHub repos of some well known open source projects, picked a semi-random file, and found the following:

Etcd lease/lessor.go

```
func (le *lessor) isPrimary() bool
```

Kubernetes service/service_controller.go

```
func (s *ServiceController) needsUpdate(oldService *v1.Service, newService *v1.Service) bool

func portsEqualForLB(x, y *v1.Service) bool

func portSlicesEqualForLB(x, y []*v1.ServicePort) bool
```

Consul agent/acl.go

```
func (m *aclManager) isDisabled() bool
```

Docker Moby (open source upstream of Docker) cli/cobra.go

```
func hasSubCommands(cmd *cobra.Command) bool

func hasManagementSubCommands(cmd *cobra.Command) bool
```

I would say that these four projects represent some of the most well reviewed and famous go code in existence. It seems that the is/has pattern is very prevalent although not the only pattern. If you choose this pattern you will certainly be able to defend your choice as a de facto idiom.

Go idiomatic way to name boolean predicate functions

Solution

Problem