diff options
Diffstat (limited to 'Doc/ref')
| -rw-r--r-- | Doc/ref/ref3.tex | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/Doc/ref/ref3.tex b/Doc/ref/ref3.tex index f339676..f670ce0 100644 --- a/Doc/ref/ref3.tex +++ b/Doc/ref/ref3.tex @@ -1052,6 +1052,35 @@ extracting a slice may not make sense. (One example of this is the \subsection{Basic customization\label{customization}} +\begin{methoddesc}[object]{__new__}{cls\optional{, \moreargs}} +Called to create a new instance of class \var{cls}. \method{__new__()} +is a static method (special-cased so you need not declare it as such) +that takes the class of which an instance was requested as its first +argument. The remaining arguments are those passed to the object +constructor expression (the call to the class). The return value of +\method{__new__()} should be the new object instance (usually an +instance of \var{cls}). + +Typical implementations create a new instance of the class by invoking +the superclass's \method{__new__()} method using +\samp{super(\var{currentclass}, \var{cls}).__new__(\var{cls}[, ...])} +with appropriate arguments and then modifying the newly-created instance +as necessary before returning it. + +If \method{__new__()} returns an instance of \var{cls}, then the new +instance's \method{__init__()} method will be invoked like +\samp{__init__(\var{self}[, ...])}, where \var{self} is the new instance +and the remaining arguments are the same as were passed to +\method{__new__()}. + +If \method{__new__()} does not return an instance of \var{cls}, then the +new instance's \method{__init__()} method will not be invoked. + +\method{__new__()} is intended mainly to allow subclasses of +immutable types (like int, str, or tuple) to customize instance +creation. +\end{methoddesc} + \begin{methoddesc}[object]{__init__}{self\optional{, \moreargs}} Called\indexii{class}{constructor} when the instance is created. The arguments are those passed to the class constructor expression. If a |