instructions.md

In this exercise you'll be checking permissions of user accounts on an internet forum. The forum supports three different permissions:

• Read
• Write
• Delete

There are three types of accounts, each with different default permissions:

• Guests: can read posts.
• Users: can read and write posts.
• Moderators: can read, write and delete posts.

Sometimes individual permissions are modified, for example giving a guest account the permission to also write posts.

You have four tasks.

1. Get default permissions for an account type

First, define an AccountType enum to represent the three account types. Next, define a Permission enum to represent the three permission types and two extra ones: one for having no permissions at all, and for having all permissions.

Then implement the (static) Permissions.Default() method to return the default permissions for a specific account type:

Permissions.Default(AccountType.Guest)
// => Permission.Read

2. Grant a permission

Implement the (static) Permissions.Grant() method that grants (adds) a permission:

Permissions.Grant(current: Permission.None, grant: Permission.Read)
// => Permission.Read

3. Revoke a permission

Implement the (static) Permissions.Revoke() method that revokes (removes) a permission:

Permissions.Revoke(current: Permission.Read, grant: Permission.Read)
// => Permission.None

4. Check for a permission

Implement the (static) Permissions.Check() method that takes the current account's permissions and checks if the account is authorized for a given permission:

Permissions.Check(current: Permission.Write, check: Permission.Read)
// => false