114 lines
4.4 KiB
TeX
114 lines
4.4 KiB
TeX
\section{\module{UserDict} ---
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Class wrapper for dictionary objects}
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\declaremodule{standard}{UserDict}
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\modulesynopsis{Class wrapper for dictionary objects.}
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This module defines a class that acts as a wrapper around
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dictionary objects. It is a useful base class for
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your own dictionary-like classes, which can inherit from
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them and override existing methods or add new ones. In this way one
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can add new behaviors to dictionaries.
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The \module{UserDict} module defines the \class{UserDict} class:
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\begin{classdesc}{UserDict}{\optional{initialdata}}
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Return a class instance that simulates a dictionary. The instance's
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contents are kept in a regular dictionary, which is accessible via the
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\member{data} attribute of \class{UserDict} instances. If
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\var{initialdata} is provided, \member{data} is initialized with its
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contents; note that a reference to \var{initialdata} will not be kept,
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allowing it be used used for other purposes.
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\end{classdesc}
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In addition to supporting the methods and operations of mappings (see
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section \ref{typesmapping}), \class{UserDict} instances provide the
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following attribute:
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\begin{memberdesc}{data}
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A real dictionary used to store the contents of the \class{UserDict}
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class.
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\end{memberdesc}
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\section{\module{UserList} ---
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Class wrapper for list objects}
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\declaremodule{standard}{UserList}
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\modulesynopsis{Class wrapper for list objects.}
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This module defines a class that acts as a wrapper around
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list objects. It is a useful base class for
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your own list-like classes, which can inherit from
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them and override existing methods or add new ones. In this way one
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can add new behaviors to lists.
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The \module{UserList} module defines the \class{UserList} class:
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\begin{classdesc}{UserList}{\optional{list}}
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Return a class instance that simulates a list. The instance's
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contents are kept in a regular list, which is accessible via the
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\member{data} attribute of \class{UserList} instances. The instance's
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contents are initially set to a copy of \var{list}, defaulting to the
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empty list \code{[]}. \var{list} can be either a regular Python list,
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or an instance of \class{UserList} (or a subclass).
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\end{classdesc}
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In addition to supporting the methods and operations of mutable
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sequences (see section \ref{typesseq}), \class{UserList} instances
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provide the following attribute:
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\begin{memberdesc}{data}
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A real Python list object used to store the contents of the
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\class{UserList} class.
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\end{memberdesc}
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\section{\module{UserString} ---
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Class wrapper for string objects}
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\declaremodule{standard}{UserString}
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\modulesynopsis{Class wrapper for string objects.}
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\moduleauthor{Peter Funk}{pf@artcom-gmbh.de}
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\sectionauthor{Peter Funk}{pf@artcom-gmbh.de}
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This module defines a class that acts as a wrapper around
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string objects. It is a useful base class for
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your own string-like classes, which can inherit from
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them and override existing methods or add new ones. In this way one
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can add new behaviors to strings.
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The \module{UserString} module defines the \class{UserString} class:
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\begin{classdesc}{UserString}{\optional{sequence}}
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Return a class instance that simulates a string or a Unicode string object.
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The instance's content is kept in a regular string or Unicode string
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object, which is accessible via the
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\member{data} attribute of \class{UserString} instances. The instance's
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contents are initially set to a copy of \var{sequence}.
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\var{sequence} can be either a regular Python string or Unicode string,
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an instance of \class{UserString} (or a subclass) or an arbitrary sequence
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which can be converted into a string.
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\end{classdesc}
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In addition to supporting the methods and operations of string or
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Unicode objects (see section \ref{typesseq}), \class{UserString} instances
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provide the following attribute:
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\begin{memberdesc}{data}
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A real Python string or Unicode object used to store the content of the
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\class{UserString} class.
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\end{memberdesc}
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\begin{classdesc}{MutableString}{\optional{sequence}}
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This class is derived from the \class{UserString} above and redefines
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strings to be \emph{mutable}. Mutable strings can't be used as
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dictionary keys, because dictionaries require \emph{immutable} objects as
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keys. The main intention of this class is to serve as an educational
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example for inheritance and necessity to remove (override) the
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\function{__hash__} method in order to trap attempts to use a
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mutable object as dictionary key, which would be otherwise very
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error prone and hard to track down.
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\end{classdesc}
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