diff options
Diffstat (limited to 'doc/syntax/modules_and_classes.rdoc')
| -rw-r--r-- | doc/syntax/modules_and_classes.rdoc | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/doc/syntax/modules_and_classes.rdoc b/doc/syntax/modules_and_classes.rdoc index 9c83a319b9..9e05c5c774 100644 --- a/doc/syntax/modules_and_classes.rdoc +++ b/doc/syntax/modules_and_classes.rdoc @@ -40,9 +40,9 @@ functionality: remove_method :my_method end -Reopening classes is a very powerful feature of Ruby, but it is best to only -reopen classes you own. Reopening classes you do not own may lead to naming -conflicts or difficult to diagnose bugs. +Reopening modules (or classes) is a very powerful feature of Ruby, but it is +best to only reopen modules you own. Reopening modules you do not own may lead +to naming conflicts or difficult to diagnose bugs. == Nesting @@ -155,7 +155,7 @@ Ruby has three types of visibility. The default is +public+. A public method may be called from any other object. The second visibility is +protected+. When calling a protected method the -receiver must inherit the Class or Module which defines the method. Otherwise a +sender must inherit the Class or Module which defines the method. Otherwise a NoMethodError will be raised. Protected visibility is most frequently used to define <code>==</code> and @@ -259,6 +259,28 @@ includes a minimum of built-in methods. You can use BasicObject to create an independent inheritance structure. See the BasicObject documentation for further details. +Just like modules, classes can also be reopened. You can omit its superclass +when you reopen a class. Specifying a different superclass than the previous +definition will raise an error. + + class C + end + + class D < C + end + + # OK + class D < C + end + + # OK + class D + end + + # TypeError: superclass mismatch for class D + class D < String + end + == Inheritance Any method defined on a class is callable from its subclass: |