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Diffstat (limited to 'Doc/lib/libfunctools.tex')
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diff --git a/Doc/lib/libfunctools.tex b/Doc/lib/libfunctools.tex index a25a23a..33a6f52 100644 --- a/Doc/lib/libfunctools.tex +++ b/Doc/lib/libfunctools.tex @@ -5,6 +5,7 @@ \moduleauthor{Peter Harris}{scav@blueyonder.co.uk} \moduleauthor{Raymond Hettinger}{python@rcn.com} +\moduleauthor{Nick Coghlan}{ncoghlan@gmail.com} \sectionauthor{Peter Harris}{scav@blueyonder.co.uk} \modulesynopsis{Higher-order functions and operations on callable objects.} @@ -50,6 +51,51 @@ two: \end{verbatim} \end{funcdesc} +\begin{funcdesc}{update_wrapper} +{wrapper, wrapped\optional{, assigned}\optional{, updated}} +Update a wrapper function to look like the wrapped function. The optional +arguments are tuples to specify which attributes of the original +function are assigned directly to the matching attributes on the wrapper +function and which attributes of the wrapper function are updated with +the corresponding attributes from the original function. The default +values for these arguments are the module level constants +\var{WRAPPER_ASSIGNMENTS} (which assigns to the wrapper function's name, +module and documentation string) and \var{WRAPPER_UPDATES} (which +updates the wrapper function's instance dictionary). + +The main intended use for this function is in decorator functions +which wrap the decorated function and return the wrapper. If the +wrapper function is not updated, the metadata of the returned function +will reflect the wrapper definition rather than the original function +definition, which is typically less than helpful. +\end{funcdesc} + +\begin{funcdesc}{wraps} +{wrapped\optional{, assigned}\optional{, updated}} +This is a convenience function for invoking +\code{partial(update_wrapper, wrapped=wrapped, assigned=assigned, updated=updated)} +as a function decorator when defining a wrapper function. For example: + \begin{verbatim} + >>> def my_decorator(f): + ... @wraps(f) + ... def wrapper(*args, **kwds): + ... print 'Calling decorated function' + ... return f(*args, **kwds) + ... return wrapper + ... + >>> @my_decorator + ... def example(): + ... print 'Called example function' + ... + >>> example() + Calling decorated function + Called example function + >>> example.__name__ + 'example' + \end{verbatim} +Without the use of this decorator factory, the name of the example +function would have been \code{'wrapper'}. +\end{funcdesc} \subsection{\class{partial} Objects \label{partial-objects}} |