From e7beaa5339b96303c90fbae4554a6d6189201306 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Glauco=20Cust=C3=B3dio?= <glauco.custodio@gmail.com>
Date: Sat, 4 May 2024 07:37:11 +0100
Subject: [PATCH] document attribute method overriding (#36)

---
 README.md | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/README.md b/README.md
index 063ccb3..fd778a9 100644
--- a/README.md
+++ b/README.md
@@ -65,6 +65,7 @@ $ gem install shale
 * [Using methods to extract and generate data](#using-methods-to-extract-and-generate-data)
 * [Delegating fields to child attributes](#delegating-fields-to-child-attributes)
 * [Additional options](#additional-options)
+* [Overriding attribute methods](#overriding-attribute-methods)
 * [Using custom models](#using-custom-models)
 * [Supported types](#supported-types)
 * [Writing your own type](#writing-your-own-type)
@@ -1108,6 +1109,40 @@ Person.to_json(person, allow_nan: true)
 # }
 ```
 
+### Overriding attribute methods
+
+It's possible to override an attribute method to change its output:
+
+```ruby
+class Person < Shale::Mapper
+  attribute :gender, Shale::Type::String
+
+  def gender
+    if super == 'm'
+      'male'
+    else
+      'female'
+    end
+  end
+end
+
+puts Person.from_json('{"gender":"m"}')
+
+# =>
+#
+# #<Person:0x00007f9bc3086d60
+#  @gender="male">
+```
+
+Be conscious that the original attribute value will be lost after its transformation though:
+
+```ruby
+puts User.from_json('{"gender":"m"}').to_json
+# => {"gender":"male"}
+```
+
+It'll no longer return gender `m`.
+
 ### Using custom models
 
 By default Shale combines mapper and model into one class. If you want to use your own classes