Added \label{}s for logical addressing.
diff --git a/Doc/tut/tut.tex b/Doc/tut/tut.tex
index 32e7617..0d1ccef 100644
--- a/Doc/tut/tut.tex
+++ b/Doc/tut/tut.tex
@@ -66,7 +66,8 @@
\chapter{Whetting Your Appetite}
-\section{Introduction}
+%\section{Introduction}
+\label{intro}
If you ever wrote a large shell script, you probably know this
feeling: you'd love to add yet another feature, but it's already so
@@ -138,6 +139,7 @@
it is encouraged!
\section{Where From Here}
+\label{where}
Now that you are all excited about Python, you'll want to examine it
in some more detail. Since the best way to learn a language is
@@ -154,8 +156,10 @@
and user-defined classes.
\chapter{Using the Python Interpreter}
+\label{using}
\section{Invoking the Interpreter}
+\label{invoking}
The Python interpreter is usually installed as \file{/usr/local/bin/python}
on those machines where it is available; putting \file{/usr/local/bin} in
@@ -165,7 +169,7 @@
\begin{verbatim}
python
\end{verbatim}
-%
+
to the shell. Since the choice of the directory where the interpreter
lives is an installation option, other places are possible; check with
your local Python guru or system administrator. (E.g.,
@@ -217,6 +221,7 @@
previous paragraph.)
\subsection{Argument Passing}
+\label{argPassing}
When known to the interpreter, the script name and additional
arguments thereafter are passed to the script in the variable
@@ -230,6 +235,7 @@
command to handle.
\subsection{Interactive Mode}
+\label{interactive}
When commands are read from a tty, the interpreter is said to be in
\emph{interactive mode}. In this mode it prompts for the next command
@@ -249,8 +255,10 @@
\end{verbatim}
\section{The Interpreter and its Environment}
+\label{interp}
\subsection{Error Handling}
+\label{error}
When an error occurs, the interpreter prints an error
message and a stack trace. In interactive mode, it then returns to
@@ -275,6 +283,7 @@
\code{try} statement.
\subsection{Executable Python scripts}
+\label{scripts}
On BSD'ish \UNIX{} systems, Python scripts can be made directly
executable, like shell scripts, by putting the line
@@ -282,12 +291,13 @@
\begin{verbatim}
#! /usr/bin/env python
\end{verbatim}
-%
+
(assuming that the interpreter is on the user's PATH) at the beginning
of the script and giving the file an executable mode. The \samp{\#!}
must be the first two characters of the file.
\subsection{The Interactive Startup File}
+\label{startup}
% XXX This should probably be dumped in an appendix, since most people
% don't use Python interactively in non-trivial ways.
@@ -319,6 +329,7 @@
\end{verbatim}
\chapter{An Informal Introduction to Python}
+\label{informal}
In the following examples, input and output are distinguished by the
presence or absence of prompts (\samp{>>> } and \samp{... }): to repeat
@@ -334,11 +345,13 @@
you must type a blank line; this is used to end a multi-line command.
\section{Using Python as a Calculator}
+\label{calculator}
Let's try some simple Python commands. Start the interpreter and wait
for the primary prompt, \samp{>>> }. (It shouldn't take long.)
\subsection{Numbers}
+\label{numbers}
The interpreter acts as a simple calculator: you can type an
expression at it and it will write the value. Expression syntax is
@@ -362,7 +375,7 @@
>>> 7/-3
-3
\end{verbatim}
-%
+
Like in \C{}, the equal sign (\code{=}) is used to assign a value to a
variable. The value of an assignment is not written:
@@ -465,6 +478,7 @@
its magic behavior.
\subsection{Strings}
+\label{strings}
Besides numbers, Python can also manipulate strings, which can be
expressed in several ways. They can be enclosed in single quotes or
@@ -484,7 +498,7 @@
>>> '"Isn\'t," she said.'
'"Isn\'t," she said.'
\end{verbatim}
-%
+
String literals can span multiple lines in several ways. Newlines can
be escaped with backslashes, e.g.:
@@ -523,7 +537,7 @@
-h Display this usage message
-H hostname Hostname to connect to
\end{verbatim}
-%
+
The interpreter prints the result of string operations in the same way
as they are typed for input: inside quotes, and with quotes and other
funny characters escaped by backslashes, to show the precise
@@ -542,7 +556,7 @@
>>> '<' + word*5 + '>'
'<HelpAHelpAHelpAHelpAHelpA>'
\end{verbatim}
-%
+
Two string literals next to each other are automatically concatenated;
the first line above could also have been written \samp{word = 'Help'
'A'}; this only works with two literals, not with arbitrary string expressions.
@@ -561,7 +575,7 @@
>>> word[2:4]
'lp'
\end{verbatim}
-%
+
Slice indices have useful defaults; an omitted first index defaults to
zero, an omitted second index defaults to the size of the string being
sliced.
@@ -572,7 +586,7 @@
>>> word[2:] # All but the first two characters
'lpA'
\end{verbatim}
-%
+
Here's a useful invariant of slice operations: \code{s[:i] + s[i:]}
equals \code{s}.
@@ -582,7 +596,7 @@
>>> word[:3] + word[3:]
'HelpA'
\end{verbatim}
-%
+
Degenerate slice indices are handled gracefully: an index that is too
large is replaced by the string size, an upper bound smaller than the
lower bound returns an empty string.
@@ -595,7 +609,7 @@
>>> word[2:1]
''
\end{verbatim}
-%
+
Indices may be negative numbers, to start counting from the right.
For example:
@@ -609,7 +623,7 @@
>>> word[:-2] # All but the last two characters
'Hel'
\end{verbatim}
-%
+
But note that -0 is really the same as 0, so it does not count from
the right!
@@ -617,7 +631,7 @@
>>> word[-0] # (since -0 equals 0)
'H'
\end{verbatim}
-%
+
Out-of-range negative slice indices are truncated, but don't try this
for single-element (non-slice) indices:
@@ -629,7 +643,7 @@
File "<stdin>", line 1
IndexError: string index out of range
\end{verbatim}
-%
+
The best way to remember how slices work is to think of the indices as
pointing \emph{between} characters, with the left edge of the first
character numbered 0. Then the right edge of the last character of a
@@ -642,7 +656,7 @@
0 1 2 3 4 5
-5 -4 -3 -2 -1
\end{verbatim}
-%
+
The first row of numbers gives the position of the indices 0...5 in
the string; the second row gives the corresponding negative indices.
The slice from \var{i} to \var{j} consists of all characters between
@@ -661,6 +675,7 @@
\end{verbatim}
\subsection{Lists}
+\label{lists}
Python knows a number of \emph{compound} data types, used to group
together other values. The most versatile is the \emph{list}, which
@@ -672,7 +687,7 @@
>>> a
['spam', 'eggs', 100, 1234]
\end{verbatim}
-%
+
Like string indices, list indices start at 0, and lists can be sliced,
concatenated and so on:
@@ -690,7 +705,7 @@
>>> 3*a[:3] + ['Boe!']
['spam', 'eggs', 100, 'spam', 'eggs', 100, 'spam', 'eggs', 100, 'Boe!']
\end{verbatim}
-%
+
Unlike strings, which are \emph{immutable}, it is possible to change
individual elements of a list:
@@ -701,7 +716,7 @@
>>> a
['spam', 'eggs', 123, 1234]
\end{verbatim}
-%
+
Assignment to slices is also possible, and this can even change the size
of the list:
@@ -722,14 +737,14 @@
>>> a
[123, 'bletch', 'xyzzy', 1234, 123, 'bletch', 'xyzzy', 1234]
\end{verbatim}
-%
+
The built-in function \function{len()} also applies to lists:
\begin{verbatim}
>>> len(a)
8
\end{verbatim}
-%
+
It is possible to nest lists (create lists containing other lists),
for example:
@@ -748,11 +763,12 @@
>>> q
[2, 3, 'xtra']
\end{verbatim}
-%
+
Note that in the last example, \code{p[1]} and \code{q} really refer to
the same object! We'll come back to \emph{object semantics} later.
\section{First Steps Towards Programming}
+\label{firstSteps}
Of course, we can use Python for more complicated tasks than adding
two and two together. For instance, we can write an initial
@@ -773,7 +789,7 @@
5
8
\end{verbatim}
-%
+
This example introduces several new features.
\begin{itemize}
@@ -819,7 +835,7 @@
>>> print 'The value of i is', i
The value of i is 65536
\end{verbatim}
-%
+
A trailing comma avoids the newline after the output:
\begin{verbatim}
@@ -830,7 +846,7 @@
...
1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987
\end{verbatim}
-%
+
Note that the interpreter inserts a newline before it prints the next
prompt if the last line was not completed.
@@ -838,12 +854,14 @@
\chapter{More Control Flow Tools}
+\label{moreControl}
Besides the \keyword{while} statement just introduced, Python knows
the usual control flow statements known from other languages, with
some twists.
\section{If Statements}
+\label{if}
Perhaps the most well-known statement type is the \keyword{if}
statement. For example:
@@ -860,7 +878,7 @@
... print 'More'
...
\end{verbatim}
-%
+
There can be zero or more \keyword{elif} parts, and the \keyword{else}
part is optional. The keyword `\keyword{elif}' is short for `else
if', and is useful to avoid excessive indentation. An
@@ -872,6 +890,7 @@
\emph{case} statements found in other languages.
\section{For Statements}
+\label{for}
The \keyword{for} statement in Python differs a bit from what you may be
used to in \C{} or Pascal. Rather than always iterating over an
@@ -891,7 +910,7 @@
window 6
defenestrate 12
\end{verbatim}
-%
+
It is not safe to modify the sequence being iterated over in the loop
(this can only happen for mutable sequence types, i.e., lists). If
you need to modify the list you are iterating over, e.g., duplicate
@@ -907,6 +926,7 @@
\end{verbatim}
\section{The \sectcode{range()} Function}
+\label{range}
If you do need to iterate over a sequence of numbers, the built-in
function \function{range()} comes in handy. It generates lists
@@ -916,7 +936,7 @@
>>> range(10)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
\end{verbatim}
-%
+
The given end point is never part of the generated list;
\code{range(10)} generates a list of 10 values, exactly the legal
indices for items of a sequence of length 10. It is possible to let
@@ -931,7 +951,7 @@
>>> range(-10, -100, -30)
[-10, -40, -70]
\end{verbatim}
-%
+
To iterate over the indices of a sequence, combine \function{range()}
and \function{len()} as follows:
@@ -948,6 +968,7 @@
\end{verbatim}
\section{Break and Continue Statements, and Else Clauses on Loops}
+\label{break}
The \keyword{break} statement, like in \C{}, breaks out of the smallest
enclosing \keyword{for} or \keyword{while} loop.
@@ -982,6 +1003,7 @@
\end{verbatim}
\section{Pass Statements}
+\label{pass}
The \keyword{pass} statement does nothing.
It can be used when a statement is required syntactically but the
@@ -995,6 +1017,7 @@
\end{verbatim}
\section{Defining Functions}
+\label{functions}
We can create a function that writes the Fibonacci series to an
arbitrary boundary:
@@ -1011,7 +1034,7 @@
... fib(2000)
1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597
\end{verbatim}
-%
+
The keyword \keyword{def} introduces a function \emph{definition}. It
must be followed by the function name and the parenthesized list of
formal parameters. The statements that form the body of the function
@@ -1058,7 +1081,7 @@
>>> f(100)
1 1 2 3 5 8 13 21 34 55 89
\end{verbatim}
-%
+
You might object that \code{fib} is not a function but a procedure. In
Python, like in \C{}, procedures are just functions that don't return a
value. In fact, technically speaking, procedures do return a value,
@@ -1071,7 +1094,7 @@
>>> print fib(0)
None
\end{verbatim}
-%
+
It is simple to write a function that returns a list of the numbers of
the Fibonacci series, instead of printing it:
@@ -1118,11 +1141,13 @@
\end{itemize}
\section{More on Defining Functions}
+\label{defining}
It is also possible to define functions with a variable number of
arguments. There are three forms, which can be combined.
\subsection{Default Argument Values}
+\label{defaultArgs}
The most useful form is to specify a default value for one or more
arguments. This creates a function that can be called with fewer
@@ -1156,6 +1181,7 @@
will print \code{5}.
\subsection{Keyword Arguments}
+\label{keywordArgs}
Functions can also be called using
keyword arguments of the form \samp{\var{keyword} = \var{value}}. For
@@ -1236,6 +1262,7 @@
\end{verbatim}
\subsection{Arbitrary Argument Lists}
+\label{arbitraryArgs}
Finally, the least frequently used option is to specify that a
function can be called with an arbitrary number of arguments. These
@@ -1248,11 +1275,13 @@
\end{verbatim}
\chapter{Data Structures}
+\label{structures}
This chapter describes some things you've learned about already in
more detail, and adds some new things as well.
\section{More on Lists}
+\label{moreLists}
The list data type has some more methods. Here are all of the methods
of list objects:
@@ -1311,6 +1340,7 @@
\end{verbatim}
\subsection{Functional Programming Tools}
+\label{functional}
There are three built-in functions that are very useful when used with
lists: \function{filter()}, \function{map()}, and \function{reduce()}.
@@ -1389,6 +1419,7 @@
\end{verbatim}
\section{The \sectcode{del} statement}
+\label{del}
There is a way to remove an item from a list given its index instead
of its value: the \code{del} statement. This can also be used to
@@ -1405,18 +1436,19 @@
>>> a
[1, 66.6, 1234.5]
\end{verbatim}
-%
-\code{del} can also be used to delete entire variables:
+
+\keyword{del} can also be used to delete entire variables:
\begin{verbatim}
>>> del a
\end{verbatim}
-%
+
Referencing the name \code{a} hereafter is an error (at least until
-another value is assigned to it). We'll find other uses for \code{del}
-later.
+another value is assigned to it). We'll find other uses for
+\keyword{del} later.
\section{Tuples and Sequences}
+\label{tuples}
We saw that lists and strings have many common properties, e.g.,
indexing and slicing operations. They are two examples of
@@ -1438,7 +1470,7 @@
>>> u
((12345, 54321, 'hello!'), (1, 2, 3, 4, 5))
\end{verbatim}
-%
+
As you see, on output tuples are alway enclosed in parentheses, so
that nested tuples are interpreted correctly; they may be input with
or without surrounding parentheses, although often parentheses are
@@ -1467,7 +1499,7 @@
>>> singleton
('hello',)
\end{verbatim}
-%
+
The statement \code{t = 12345, 54321, 'hello!'} is an example of
\emph{tuple packing}: the values \code{12345}, \code{54321} and
\code{'hello!'} are packed together in a tuple. The reverse operation
@@ -1476,7 +1508,7 @@
\begin{verbatim}
>>> x, y, z = t
\end{verbatim}
-%
+
This is called, appropriately enough, \emph{tuple unpacking}. Tuple
unpacking requires that the list of variables on the left has the same
number of elements as the length of the tuple. Note that multiple
@@ -1493,6 +1525,7 @@
\end{verbatim}
\section{Dictionaries}
+\label{dictionaries}
Another useful data type built into Python is the \emph{dictionary}.
Dictionaries are sometimes found in other languages as ``associative
@@ -1545,6 +1578,7 @@
\end{verbatim}
\section{More on Conditions}
+\label{conditions}
The conditions used in \code{while} and \code{if} statements above can
contain other operators besides comparisons.
@@ -1584,10 +1618,11 @@
>>> non_null
'Trondheim'
\end{verbatim}
-%
+
Note that in Python, unlike \C{}, assignment cannot occur inside expressions.
\section{Comparing Sequences and Other Types}
+\label{comparing}
Sequence objects may be compared to other objects with the same
sequence type. The comparison uses \emph{lexicographical} ordering:
@@ -1611,7 +1646,7 @@
(1, 2, 3) = (1.0, 2.0, 3.0)
(1, 2, ('aa', 'ab')) < (1, 2, ('abc', 'a'), 4)
\end{verbatim}
-%
+
Note that comparing objects of different types is legal. The outcome
is deterministic but arbitrary: the types are ordered by their name.
Thus, a list is always smaller than a string, a string is always
@@ -1625,6 +1660,7 @@
\chapter{Modules}
+\label{modules}
If you quit from the Python interpreter and enter it again, the
definitions you have made (functions and variables) are lost.
@@ -1668,14 +1704,14 @@
a, b = b, a+b
return result
\end{verbatim}
-%
+
Now enter the Python interpreter and import this module with the
following command:
\begin{verbatim}
>>> import fibo
\end{verbatim}
-%
+
This does not enter the names of the functions defined in
\code{fibo}
directly in the current symbol table; it only enters the module name
@@ -1702,6 +1738,7 @@
\section{More on Modules}
+\label{moreModules}
A module can contain executable statements as well as function
definitions.
@@ -1743,7 +1780,7 @@
>>> fib(500)
1 1 2 3 5 8 13 21 34 55 89 144 233 377
\end{verbatim}
-%
+
This does not introduce the module name from which the imports are taken
in the local symbol table (so in the example, \code{fibo} is not
defined).
@@ -1755,11 +1792,12 @@
>>> fib(500)
1 1 2 3 5 8 13 21 34 55 89 144 233 377
\end{verbatim}
-%
+
This imports all names except those beginning with an underscore
(\code{_}).
\subsection{The Module Search Path}
+\label{searchPath}
When a module named \module{spam} is imported, the interpreter searches
for a file named \file{spam.py} in the current directory,
@@ -1801,6 +1839,7 @@
% XXX Should optimization with -O be covered here?
\section{Standard Modules}
+\label{standardModules}
Python comes with a library of standard modules, described in a separate
document, the \emph{Python Library Reference} (``Library Reference''
@@ -1826,7 +1865,7 @@
Yuck!
C>
\end{verbatim}
-%
+
These two variables are only defined if the interpreter is in
interactive mode.
@@ -1847,6 +1886,7 @@
\end{verbatim}
\section{The \sectcode{dir()} function}
+\label{dir}
The built-in function \function{dir()} is used to find out which names
a module defines. It returns a sorted list of strings:
@@ -1860,7 +1900,7 @@
'maxint', 'modules', 'path', 'ps1', 'ps2', 'setprofile', 'settrace',
'stderr', 'stdin', 'stdout', 'version']
\end{verbatim}
-%
+
Without arguments, \function{dir()} lists the names you have defined
currently:
@@ -1871,7 +1911,7 @@
>>> dir()
['__name__', 'a', 'fib', 'fibo', 'sys']
\end{verbatim}
-%
+
Note that it lists all types of names: variables, modules, functions, etc.
\function{dir()} does not list the names of built-in functions and
@@ -1894,6 +1934,7 @@
\chapter{Input and Output}
+\label{io}
There are several ways to present the output of a program; data can be
printed in a human-readable form, or written to a file for future use.
@@ -1943,7 +1984,7 @@
... `x, y, ('spam', 'eggs')`
"(31.4, 40000, ('spam', 'eggs'))"
\end{verbatim}
-%
+
Here are two ways to write a table of squares and cubes:
\begin{verbatim}
@@ -1977,7 +2018,7 @@
9 81 729
10 100 1000
\end{verbatim}
-%
+
(Note that one space between each column was added by the way
\keyword{print} works: it always adds spaces between its arguments.)
@@ -2050,6 +2091,8 @@
local variables.
\section{Reading and Writing Files}
+\label{files}
+
% Opening files
\function{open()} returns a file object, and is most commonly used with
two arguments: \samp{open(\var{filename}, \var{mode})}.
@@ -2059,7 +2102,7 @@
>>> print f
<open file '/tmp/workfile', mode 'w' at 80a0960>
\end{verbatim}
-%
+
The first argument is a string containing the filename. The second
argument is another string containing a few characters describing the
way in which the file will be used. \var{mode} can be \code{'r'} when
@@ -2081,6 +2124,7 @@
writing such files.
\subsection{Methods of file objects}
+\label{fileMethods}
The rest of the examples in this section will assume that a file
object called \code{f} has already been created.
@@ -2099,7 +2143,7 @@
>>> f.read()
''
\end{verbatim}
-%
+
\code{f.readline()} reads a single line from the file; a newline
character (\code{\e n}) is left at the end of the string, and is only
omitted on the last line of the file if the file doesn't end in a
@@ -2116,7 +2160,7 @@
>>> f.readline()
''
\end{verbatim}
-%
+
\code{f.readlines()} uses \code{f.readline()} repeatedly, and returns
a list containing all the lines of data in the file.
@@ -2124,14 +2168,14 @@
>>> f.readlines()
['This is the first line of the file.\012', 'Second line of the file\012']
\end{verbatim}
-%
+
\code{f.write(\var{string})} writes the contents of \var{string} to
the file, returning \code{None}.
\begin{verbatim}
>>> f.write('This is a test\n')
\end{verbatim}
-%
+
\code{f.tell()} returns an integer giving the file object's current
position in the file, measured in bytes from the beginning of the
file. To change the file object's position, use
@@ -2153,7 +2197,7 @@
>>> f.read(1)
'd'
\end{verbatim}
-%
+
When you're done with a file, call \code{f.close()} to close it and
free up any system resources taken up by the open file. After calling
\code{f.close()}, attempts to use the file object will automatically fail.
@@ -2165,12 +2209,13 @@
File "<stdin>", line 1, in ?
ValueError: I/O operation on closed file
\end{verbatim}
-%
+
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 pickle module}
+\label{pickle}
Strings can easily be written to and read from a file. Numbers take a
bit more effort, since the \method{read()} method only returns
@@ -2197,14 +2242,14 @@
\begin{verbatim}
pickle.dump(x, f)
\end{verbatim}
-%
+
To unpickle the object again, if \code{f} is a file object which has
been opened for reading:
\begin{verbatim}
x = pickle.load(f)
\end{verbatim}
-%
+
(There are other variants of this, used when pickling many objects or
when you don't want to write the pickled data to a file; consult the
complete documentation for \module{pickle} in the Library Reference.)
@@ -2220,6 +2265,7 @@
\chapter{Errors and Exceptions}
+\label{errors}
Until now error messages haven't been more than mentioned, but if you
have tried out the examples you have probably seen some. There are
@@ -2227,6 +2273,7 @@
and \emph{exceptions}.
\section{Syntax Errors}
+\label{syntaxErrors}
Syntax errors, also known as parsing errors, are perhaps the most common
kind of complaint you get while you are still learning Python:
@@ -2238,7 +2285,7 @@
^
SyntaxError: invalid syntax
\end{verbatim}
-%
+
The parser repeats the offending line and displays a little `arrow'
pointing at the earliest point in the line where the error was detected.
The error is caused by (or at least detected at) the token
@@ -2249,6 +2296,7 @@
the input came from a script.
\section{Exceptions}
+\label{exceptions}
Even if a statement or expression is syntactically correct, it may
cause an error when an attempt is made to execute it.
@@ -2271,7 +2319,7 @@
File "<stdin>", line 1
TypeError: illegal argument type for built-in operation
\end{verbatim}
-%
+
The last line of the error message indicates what happened.
Exceptions come in different types, and the type is printed as part of
the message: the types in the example are
@@ -2298,6 +2346,7 @@
meanings.
\section{Handling Exceptions}
+\label{handling}
It is possible to write programs that handle selected exceptions.
Look at the following example, which prints a table of inverses of
@@ -2317,7 +2366,7 @@
0 *** has no inverse ***
10 0.1
\end{verbatim}
-%
+
The \keyword{try} statement works as follows.
\begin{itemize}
\item
@@ -2352,7 +2401,7 @@
... except (RuntimeError, TypeError, NameError):
... pass
\end{verbatim}
-%
+
The last except clause may omit the exception name(s), to serve as a
wildcard.
Use this with extreme caution, since it is easy to mask a real
@@ -2390,7 +2439,7 @@
...
name spam undefined
\end{verbatim}
-%
+
If an exception has an argument, it is printed as the last part
(`detail') of the message for unhandled exceptions.
@@ -2410,9 +2459,10 @@
...
Handling run-time error: integer division or modulo
\end{verbatim}
-%
+
\section{Raising Exceptions}
+\label{raising}
The \keyword{raise} statement allows the programmer to force a
specified exception to occur.
@@ -2424,14 +2474,14 @@
File "<stdin>", line 1
NameError: HiThere
\end{verbatim}
-%
+
The first argument to \keyword{raise} names the exception to be
raised. The optional second argument specifies the exception's
argument.
-%
\section{User-defined Exceptions}
+\label{userExceptions}
Programs may name their own exceptions by assigning a string to a
variable.
@@ -2450,13 +2500,13 @@
File "<stdin>", line 1
my_exc: 1
\end{verbatim}
-%
+
Many standard modules use this to report errors that may occur in
functions they define.
-%
\section{Defining Clean-up Actions}
+\label{cleanup}
The \keyword{try} statement has another optional clause which is
intended to define clean-up actions that must be executed under all
@@ -2473,7 +2523,7 @@
File "<stdin>", line 2
KeyboardInterrupt
\end{verbatim}
-%
+
A \emph{finally clause} is executed whether or not an exception has
occurred in the try clause. When an exception has occurred, it is
re-raised after the finally clause is executed. The finally clause is
@@ -2484,6 +2534,7 @@
or one finally clause, but not both.
\chapter{Classes}
+\label{classes}
Python's class mechanism adds classes to the language with a minimum
of new syntax and semantics. It is a mixture of the class mechanisms
@@ -2511,6 +2562,7 @@
subscripting etc.) can be redefined for class members.
\section{A word about terminology}
+\label{terminology}
Lacking universally accepted terminology to talk about classes, I'll
make occasional use of Smalltalk and \Cpp{} terms. (I'd use Modula-3
@@ -2543,6 +2595,7 @@
\section{Python scopes and name spaces}
+\label{scopes}
Before introducing classes, I first have to tell you something about
Python's scope rules. Class definitions play some neat tricks with
@@ -2646,12 +2699,14 @@
\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}
+\label{classDefinition}
The simplest form of class definition looks like this:
@@ -2691,6 +2746,7 @@
\subsection{Class objects}
+\label{classObjects}
Class objects support two kinds of operations: attribute references
and instantiation.
@@ -2729,6 +2785,7 @@
\subsection{Instance objects}
+\label{instanceObjects}
Now what can we do with instance objects? The only operations
understood by instance objects are attribute references. There are
@@ -2769,6 +2826,7 @@
\subsection{Method objects}
+\label{methodObjects}
Usually, a method is called immediately, e.g.:
@@ -2817,7 +2875,7 @@
\section{Random remarks}
-
+\label{remarks}
[These should perhaps be placed more carefully...]
@@ -2951,6 +3009,7 @@
\section{Inheritance}
+\label{inheritance}
Of course, a language feature would not be worthy of the name ``class''
without supporting inheritance. The syntax for a derived class
@@ -3003,6 +3062,7 @@
\subsection{Multiple inheritance}
+\label{multiple}
Python supports a limited form of multiple inheritance as well. A
class definition with multiple base classes looks as follows:
@@ -3043,6 +3103,7 @@
\section{Private variables through name mangling}
+\label{private}
There is now limited support for class-private
identifiers. Any identifier of the form \code{__spam} (at least two
@@ -3112,6 +3173,7 @@
%be removed without providing a better solution and a migration path.
\section{Odds and ends}
+\label{odds}
Sometimes it is useful to have a data type similar to the Pascal
``record'' or \C{} ``struct'', bundling together a couple of named data
@@ -3148,6 +3210,7 @@
function object corresponding to the method.
\subsection{Exceptions Can Be Classes}
+\label{exceptionClasses}
User-defined exceptions are no longer limited to being string objects
--- they can be identified by classes as well. Using this mechanism it
@@ -3206,6 +3269,7 @@
In this release, the built-in exceptions are still strings.
\chapter{What Now?}
+\label{whatNow}
Hopefully reading this tutorial has reinforced your interest in using
Python. Now what should you do?
@@ -3254,6 +3318,7 @@
% found or it elsewhere in the Tutorial?
\section{Lambda Forms}
+\label{lambda}
% XXX Where to put this? Or just leave it out?
@@ -3274,6 +3339,7 @@
\end{verbatim}
\section{Documentation Strings}
+\label{docstrings}
% XXX Where to put this? Or just leave it out?
@@ -3310,6 +3376,7 @@
\appendix\chapter{Interactive Input Editing and History Substitution}
+\label{interacting}
Some versions of the Python interpreter support editing of the current
input line and history substitution, similar to facilities found in
@@ -3319,6 +3386,7 @@
duplicate here; however, the basics are easily explained.
\section{Line Editing}
+\label{lineEditing}
If supported, input line editing is active whenever the interpreter
prints a primary or secondary prompt. The current line can be edited
@@ -3332,6 +3400,7 @@
repeated for cumulative effect.
\section{History Substitution}
+\label{history}
History substitution works as follows. All non-empty input lines
issued are saved in a history buffer, and when a new prompt is given
@@ -3343,6 +3412,7 @@
incremental reverse search; C-S starts a forward search.
\section{Key Bindings}
+\label{keyBindings}
The key bindings and some other parameters of the Readline library can
be customized by placing commands in an initialization file called
@@ -3389,6 +3459,7 @@
indented continuation lines...)
\section{Commentary}
+\label{commentary}
This facility is an enormous step forward compared to previous
versions of the interpreter; however, some wishes are left: It would