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Diffstat (limited to 'Doc/tut/tut.tex')
| -rw-r--r-- | Doc/tut/tut.tex | 160 |
1 files changed, 76 insertions, 84 deletions
diff --git a/Doc/tut/tut.tex b/Doc/tut/tut.tex index a92c7ff..d00b37e 100644 --- a/Doc/tut/tut.tex +++ b/Doc/tut/tut.tex @@ -65,7 +65,6 @@ modules described in the \emph{Python Library Reference}. \chapter{Whetting Your Appetite} -%\section{Introduction} \label{intro} If you ever wrote a large shell script, you probably know this @@ -253,7 +252,7 @@ Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam >>> \end{verbatim} -\section{The Interpreter and its Environment} +\section{The Interpreter and Its Environment} \label{interp} \subsection{Error Handling} @@ -281,7 +280,7 @@ Typing an interrupt while a command is executing raises the \code{KeyboardInterrupt} exception, which may be handled by a \code{try} statement. -\subsection{Executable Python scripts} +\subsection{Executable Python Scripts} \label{scripts} On BSD'ish \UNIX{} systems, Python scripts can be made directly @@ -1274,6 +1273,59 @@ def fprintf(file, format, *args): file.write(format % args) \end{verbatim} + +\subsection{Lambda Forms} +\label{lambda} + +By popular demand, a few features commonly found in functional +programming languages and Lisp have been added to Python. With the +\keyword{lambda} keyword, small anonymous functions can be created. +Here's a function that returns the sum of its two arguments: +\samp{lambda a, b: a+b}. Lambda forms can be used wherever function +objects are required. They are syntactically restricted to a single +expression. Semantically, they are just syntactic sugar for a normal +function definition. Like nested function definitions, lambda forms +cannot reference variables from the containing scope, but this can be +overcome through the judicious use of default argument values, e.g. + +\begin{verbatim} +def make_incrementor(n): + return lambda x, incr=n: x+incr +\end{verbatim} + +\subsection{Documentation Strings} +\label{docstrings} + +There are emerging conventions about the content and formatting of +documentation strings. + +The first line should always be a short, concise summary of the +object's purpose. For brevity, it should not explicitly state the +object's name or type, since these are available by other means +(except if the name happens to be a verb describing a function's +operation). This line should begin with a capital letter and end with +a period. + +If there are more lines in the documentation string, the second line +should be blank, visually separating the summary from the rest of the +description. The following lines should be one of more of paragraphs +describing the objects calling conventions, its side effects, etc. + +The Python parser does not strip indentation from multi-line string +literals in Python, so tools that process documentation have to strip +indentation. This is done using the following convention. The first +non-blank line \emph{after} the first line of the string determines the +amount of indentation for the entire documentation string. (We can't +use the first line since it is generally adjacent to the string's +opening quotes so its indentation is not apparent in the string +literal.) Whitespace ``equivalent'' to this indentation is then +stripped from the start of all lines of the string. Lines that are +indented less should not occur, but if they occur all their leading +whitespace should be stripped. Equivalence of whitespace should be +tested after expansion of tabs (to 8 spaces, normally). + + + \chapter{Data Structures} \label{structures} @@ -1883,7 +1935,7 @@ is not set. You can modify it using standard list operations, e.g.: >>> sys.path.append('/ufs/guido/lib/python') \end{verbatim} -\section{The \sectcode{dir()} function} +\section{The \sectcode{dir()} Function} \label{dir} The built-in function \function{dir()} is used to find out which names @@ -2124,7 +2176,7 @@ written. This behind-the-scenes modification to file data is fine for writing such files. (Note that the precise semantics of text mode on the Macintosh depends on the underlying \C{} library being used.) -\subsection{Methods of file objects} +\subsection{Methods of File Objects} \label{fileMethods} The rest of the examples in this section will assume that a file @@ -2215,7 +2267,7 @@ File objects have some additional methods, such as \method{isatty()} and \method{truncate()} which are less frequently used; consult the Library Reference for a complete guide to file objects. -\subsection{The \module{pickle} module} +\subsection{The \module{pickle} Module} \label{pickle} \refstmodindex{pickle} @@ -2563,7 +2615,7 @@ extension by the user. Also, like in \Cpp{} but unlike in Modula-3, most built-in operators with special syntax (arithmetic operators, subscripting etc.) can be redefined for class instances. -\section{A word about terminology} +\section{A Word About Terminology} \label{terminology} Lacking universally accepted terminology to talk about classes, I will @@ -2596,7 +2648,7 @@ obviates the need for two different argument passing mechanisms as in Pascal. -\section{Python scopes and name spaces} +\section{Python Scopes and Name Spaces} \label{scopes} Before introducing classes, I first have to tell you something about @@ -2700,14 +2752,14 @@ scope. (The \keyword{global} statement can be used to indicate that particular variables live in the global scope.) -\section{A first look at classes} +\section{A First Look at Classes} \label{firstClasses} Classes introduce a little bit of new syntax, three new object types, and some new semantics. -\subsection{Class definition syntax} +\subsection{Class Definition Syntax} \label{classDefinition} The simplest form of class definition looks like this: @@ -2743,11 +2795,11 @@ object} is created. This is basically a wrapper around the contents of the name space created by the class definition; we'll learn more about class objects in the next section. The original local scope (the one in effect just before the class definitions was entered) is -reinstated, and the class object is bound here to class name given in -the class definition header (\code{ClassName} in the example). +reinstated, and the class object is bound here to the class name given +in the class definition header (\class{ClassName} in the example). -\subsection{Class objects} +\subsection{Class Objects} \label{classObjects} Class objects support two kinds of operations: attribute references @@ -2786,7 +2838,7 @@ creates a new \emph{instance} of the class and assigns this object to the local variable \code{x}. -\subsection{Instance objects} +\subsection{Instance Objects} \label{instanceObjects} Now what can we do with instance objects? The only operations @@ -2824,10 +2876,11 @@ example, \code{x.f} is a valid method reference, since \code{MyClass.f} is a function, but \code{x.i} is not, since \code{MyClass.i} is not. But \code{x.f} is not the same thing as \code{MyClass.f} --- it is a \emph{method object}, not a function -object. +object.% +\obindex{method} -\subsection{Method objects} +\subsection{Method Objects} \label{methodObjects} Usually, a method is called immediately, e.g.: @@ -2876,7 +2929,7 @@ list is constructed from the instance object and the original argument list, and the function object is called with this new argument list. -\section{Random remarks} +\section{Random Remarks} \label{remarks} [These should perhaps be placed more carefully...] @@ -3063,7 +3116,7 @@ occasionally useful to clients as well. (Note that this only works if the base class is defined or imported directly in the global scope.) -\subsection{Multiple inheritance} +\subsection{Multiple Inheritance} \label{multiple} Python supports a limited form of multiple inheritance as well. A @@ -3104,10 +3157,10 @@ variables'' or data attributes used by the common base class), it is not clear that these semantics are in any way useful. -\section{Private variables through name mangling} +\section{Private Variables} \label{private} -There is now limited support for class-private +There is limited support for class-private identifiers. Any identifier of the form \code{__spam} (at least two leading underscores, at most one trailing underscore) is now textually replaced with \code{_classname__spam}, where \code{classname} is the @@ -3174,7 +3227,7 @@ class VirtualAttributes: %so that widespread experience with its use can be gained. It will not %be removed without providing a better solution and a migration path. -\section{Odds and ends} +\section{Odds and Ends} \label{odds} Sometimes it is useful to have a data type similar to the Pascal @@ -3317,70 +3370,9 @@ organizes Python workshops. See \url{http://www.python.org/psa/} for information on how to join. -\chapter{Recent Additions as of Release 1.1} - -% XXX Should the stuff in this chapter be deleted, or can a home be -% found or it elsewhere in the Tutorial? - -\section{Lambda Forms} -\label{lambda} - -% XXX Where to put this? Or just leave it out? - -By popular demand, a few features commonly found in functional -programming languages and Lisp have been added to Python. With the -\keyword{lambda} keyword, small anonymous functions can be created. -Here's a function that returns the sum of its two arguments: -\samp{lambda a, b: a+b}. Lambda forms can be used wherever function -objects are required. They are syntactically restricted to a single -expression. Semantically, they are just syntactic sugar for a normal -function definition. Like nested function definitions, lambda forms -cannot reference variables from the containing scope, but this can be -overcome through the judicious use of default argument values, e.g. - -\begin{verbatim} -def make_incrementor(n): - return lambda x, incr=n: x+incr -\end{verbatim} - -\section{Documentation Strings} -\label{docstrings} - -% XXX Where to put this? Or just leave it out? - -There are emerging conventions about the content and formatting of -documentation strings. - -The first line should always be a short, concise summary of the -object's purpose. For brevity, it should not explicitly state the -object's name or type, since these are available by other means -(except if the name happens to be a verb describing a function's -operation). This line should begin with a capital letter and end with -a period. - -If there are more lines in the documentation string, the second line -should be blank, visually separating the summary from the rest of the -description. The following lines should be one of more of paragraphs -describing the objects calling conventions, its side effects, etc. - -Some people like to copy the Emacs convention of using UPPER CASE for -function parameters --- this often saves a few words or lines. - -The Python parser does not strip indentation from multi-line string -literals in Python, so tools that process documentation have to strip -indentation. This is done using the following convention. The first -non-blank line \emph{after} the first line of the string determines the -amount of indentation for the entire documentation string. (We can't -use the first line since it is generally adjacent to the string's -opening quotes so its indentation is not apparent in the string -literal.) Whitespace ``equivalent'' to this indentation is then -stripped from the start of all lines of the string. Lines that are -indented less should not occur, but if they occur all their leading -whitespace should be stripped. Equivalence of whitespace should be -tested after expansion of tabs (to 8 spaces, normally). - +\appendix -\appendix\chapter{Interactive Input Editing and History Substitution} +\chapter{Interactive Input Editing and History Substitution} \label{interacting} Some versions of the Python interpreter support editing of the current |