diff options
Diffstat (limited to 'railties/guides/source/active_support_core_extensions.textile')
| -rw-r--r-- | railties/guides/source/active_support_core_extensions.textile | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/railties/guides/source/active_support_core_extensions.textile b/railties/guides/source/active_support_core_extensions.textile index e0c69516cf..31433d50eb 100644 --- a/railties/guides/source/active_support_core_extensions.textile +++ b/railties/guides/source/active_support_core_extensions.textile @@ -1078,6 +1078,27 @@ self.field_helpers = (FormHelper.instance_method_names - ['form_for']) NOTE: Defined in +active_support/core_ext/module/method_names.rb+ +h4. 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. + +The method +redefine_method+ prevents such a potential warning, removing the existing method before if needed. Rails uses it in a few places, for instance when it generates an association's API: + +<ruby> +redefine_method("#{reflection.name}=") do |new_value| + association = association_instance_get(reflection.name) + + if association.nil? || association.target != new_value + association = association_proxy_class.new(self, reflection) + end + + association.replace(new_value) + association_instance_set(reflection.name, new_value.nil? ? nil : association) +end +</ruby> + +NOTE: Defined in +active_support/core_ext/module/remove_method.rb+ + h3. Extensions to +Class+ h4. Class Attributes |