aboutsummaryrefslogtreecommitdiffstats
path: root/activesupport
diff options
context:
space:
mode:
authorMarcel Molina <marcel@vernix.org>2006-11-16 19:35:13 +0000
committerMarcel Molina <marcel@vernix.org>2006-11-16 19:35:13 +0000
commit309a6bd550281b60f25be28ea76a5cce5f9b377b (patch)
tree953e9d12f9fec91b3211f5d309dec276a4ea2bd9 /activesupport
parent0100a79913af60abd15351efd4a495dec0ff0474 (diff)
downloadrails-309a6bd550281b60f25be28ea76a5cce5f9b377b.tar.gz
rails-309a6bd550281b60f25be28ea76a5cce5f9b377b.tar.bz2
rails-309a6bd550281b60f25be28ea76a5cce5f9b377b.zip
Add Module#attr_accessor_with_default to initialize value of attribute before setting it. Closes #6538. [Stuart Halloway, Marcel Molina Jr.]
git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@5539 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
Diffstat (limited to 'activesupport')
-rw-r--r--activesupport/CHANGELOG2
-rw-r--r--activesupport/lib/active_support/core_ext/module.rb1
-rw-r--r--activesupport/lib/active_support/core_ext/module/attr_accessor_with_default.rb31
-rw-r--r--activesupport/test/core_ext/module/attr_accessor_with_default.rb30
4 files changed, 64 insertions, 0 deletions
diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index 432780a94e..a4f286b42f 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
*SVN*
+* Add Module#attr_accessor_with_default to initialize value of attribute before setting it. Closes #6538. [Stuart Halloway, Marcel Molina Jr.]
+
* Hash#to_xml handles keys with the same name as Kernel methods. #6613 [Catfish]
* Added Time#end_of_day to get 23:59:59 of that day [DHH]
diff --git a/activesupport/lib/active_support/core_ext/module.rb b/activesupport/lib/active_support/core_ext/module.rb
index 8d48de53dd..26c9bdf778 100644
--- a/activesupport/lib/active_support/core_ext/module.rb
+++ b/activesupport/lib/active_support/core_ext/module.rb
@@ -1,6 +1,7 @@
require File.dirname(__FILE__) + '/module/inclusion'
require File.dirname(__FILE__) + '/module/attribute_accessors'
require File.dirname(__FILE__) + '/module/attr_internal'
+require File.dirname(__FILE__) + '/module/attr_accessor_with_default'
require File.dirname(__FILE__) + '/module/delegation'
require File.dirname(__FILE__) + '/module/introspection'
require File.dirname(__FILE__) + '/module/loading'
diff --git a/activesupport/lib/active_support/core_ext/module/attr_accessor_with_default.rb b/activesupport/lib/active_support/core_ext/module/attr_accessor_with_default.rb
new file mode 100644
index 0000000000..31f14be344
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module/attr_accessor_with_default.rb
@@ -0,0 +1,31 @@
+class Module
+ # Declare an attribute accessor with an initial default return value.
+ #
+ # To give attribute <tt>:age</tt> the initial value <tt>25</tt>:
+ #
+ # class Person
+ # attr_accessor_with_default :age, 25
+ # end
+ #
+ # some_person.age
+ # => 25
+ # some_person.age = 26
+ # some_person.age
+ # => 26
+ #
+ # To give attribute <tt>:element_name</tt> a dynamic default value, evaluated
+ # in scope of self:
+ #
+ # attr_accessor_with_default(:element_name) { name.underscore }
+ #
+ def attr_accessor_with_default(sym, default = nil, &block)
+ raise 'Default value or block required' unless default || block
+ define_method(sym, block_given? ? block : Proc.new { default })
+ module_eval(<<-EVAL, __FILE__, __LINE__)
+ def #{sym}=(value)
+ class << self; attr_reader :#{sym} end
+ @#{sym} = value
+ end
+ EVAL
+ end
+end
diff --git a/activesupport/test/core_ext/module/attr_accessor_with_default.rb b/activesupport/test/core_ext/module/attr_accessor_with_default.rb
new file mode 100644
index 0000000000..8ae52ad17a
--- /dev/null
+++ b/activesupport/test/core_ext/module/attr_accessor_with_default.rb
@@ -0,0 +1,30 @@
+require File.dirname(__FILE__) + '/../../abstract_unit'
+
+class AttrWithDefaultTest < Test::Unit::TestCase
+ def setup
+ @target = Class.new do
+ def helper
+ 'helper'
+ end
+ end
+ @instance = @target.new
+ end
+
+ def test_default_arg
+ @target.attr_accessor_with_default :foo, :bar
+ assert_equal(:bar, @instance.foo)
+ @instance.foo = nil
+ assert_nil(@instance.foo)
+ end
+
+ def test_default_proc
+ @target.attr_accessor_with_default(:foo) {helper.upcase}
+ assert_equal('HELPER', @instance.foo)
+ @instance.foo = nil
+ assert_nil(@instance.foo)
+ end
+
+ def test_invalid_args
+ assert_raise(RuntimeError) {@target.attr_accessor_with_default :foo}
+ end
+end \ No newline at end of file