Validation rules composition

[System-Glitch]

Proposal

Sometimes it could be handy to be able to use another rule set inside a larger rule set by using composition. Example:

CreateUserRequest = validation.RuleSet{
    "email": {"required", "email"},
    "password": {"required", "min:6"},
}

CreateManyUsersRequest = validation.RuleSet{
    "users": {"required", "array:object"},
    "users[]": CreateUserRequest,
}

Note: could use an interface so both types ([]string{} and RuleSet) can be used as a value inside a RuleSet. Don't forget about alternative syntax too!

Possible drawbacks

None.