From 43512df990ff1bba30b4b3cfa427b314a0314623 Mon Sep 17 00:00:00 2001 From: Genadi Samokovarov Date: Mon, 29 May 2017 15:44:15 +0300 Subject: Document Module#delegate_missing_to in the guides Added a small section for it in the `Active Support Core Extensions` guide. [ci skip] --- guides/source/active_support_core_extensions.md | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'guides/source') diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md index 67bed4c8da..eb46732127 100644 --- a/guides/source/active_support_core_extensions.md +++ b/guides/source/active_support_core_extensions.md @@ -755,6 +755,8 @@ NOTE: Defined in `active_support/core_ext/module/anonymous.rb`. ### Method Delegation +#### `delegate` + The macro `delegate` offers an easy way to forward methods. Let's imagine that users in some application have login information in the `User` model but name and other data in a separate `Profile` model: @@ -837,6 +839,25 @@ In the previous example the macro generates `avatar_size` rather than `size`. NOTE: Defined in `active_support/core_ext/module/delegation.rb` +#### `delegate_missing_to` + +Imagine you would like to delegate everything missing from the `User` object, +to the `Profile` one. The `delegate_missing_to` macro lets you implement this +in a breeze: + +```ruby +class User < ApplicationRecord + has_one :profile + + delegate_missing_to :profile +end +``` + +The target can be anything callable within the object, e.g. instance variables, +methods, constants, etc. Only the public methods of the target are delegated. + +NOTE: Defined in `active_support/core_ext/module/delegation.rb` + ### Redefining Methods There are cases where you need to define a method with `define_method`, but don't know whether a method with that name already exists. If it does, a warning is issued if they are enabled. No big deal, but not clean either. -- cgit v1.2.3