module SubclassMustImplement

Either `include SubclassMustImplement` or `extend SubclassMustImplement` in your base class. Then call `subclass_must_implement` with a list of required method names as symbols. You can optionally pass in a custom error message using the `err_message` named argument.

Example 1:

class BaseFoo
  include SubclassMustImplement

  subclass_must_implement :foo, :bar, :baz
end

class Foo < BaseFoo
  def foo
    :foo
  end
end

f = Foo.new
f.foo # returns :foo
f.bar # raises a NotImplementedError that "bar" must be implemented in the subclass
f.baz # raises a NotImplementedError that "baz" must be implemented in the subclass
f.qux # raises a MethodMissing

Example 2:

class BaseBar
  extend SubclassMustImplement

  subclass_must_implement :foo, :bar, err_message: "Version expected!!!"
end

class Bar < BaseBar
  def bar
    :bar
  end
end

b = Bar.new
b.bar # return :bar
b.foo # raises a NotImplementedError with the specified error message "Version expected!!!"

Public Class Methods

default_error_message(method_name) click to toggle source

Create the default error message for the given method name. @param method_name [String|Symbol] @return [String]

# File lib/subclass_must_implement.rb, line 64
def self.default_error_message(method_name)
  "`#{method_name}` must be implemented in a subclass."
end

extended(base) click to toggle source

Inject the `subclass_must_implement` macro.

# File lib/subclass_must_implement.rb, line 51
def self.extended(base)
  base.extend ClassMethods
end

included(base) click to toggle source

Inject the `subclass_must_implement` macro.

# File lib/subclass_must_implement.rb, line 46
def self.included(base)
  base.extend ClassMethods
end

version() click to toggle source

Return the Gem version as a string. @return [String]

# File lib/subclass_must_implement.rb, line 57
def self.version
  "0.0.2"
end