* Fix typos.
* Format an example so that the identation is more obvious.
* Add a section on the decimal module to the Brief Tour Part II.
diff --git a/Doc/tut/tut.tex b/Doc/tut/tut.tex
index b00eaea..0dcac57 100644
--- a/Doc/tut/tut.tex
+++ b/Doc/tut/tut.tex
@@ -4338,7 +4338,7 @@
\method{next()}, then \method{__iter__()} can just return \code{self}:
\begin{verbatim}
->>> class Reverse:
+class Reverse:
"Iterator for looping over a sequence backwards"
def __init__(self, data):
self.data = data
@@ -4352,8 +4352,8 @@
return self.data[self.index]
>>> for char in Reverse('spam'):
- print char
-
+... print char
+...
m
a
p
@@ -4371,13 +4371,13 @@
be trivially easy to create:
\begin{verbatim}
->>> def reverse(data):
- for index in range(len(data)-1, -1, -1):
- yield data[index]
-
+def reverse(data):
+ for index in range(len(data)-1, -1, -1):
+ yield data[index]
+
>>> for char in reverse('golf'):
- print char
-
+... print char
+...
f
l
o
@@ -4894,7 +4894,7 @@
print 'The main program continues to run'
\end{verbatim}
-The principal challenge of multi-thread applications is coordinating
+The principal challenge of multi-threaded applications is coordinating
threads that share data or other resources. To that end, the threading
module provides a number of synchronization primitives including locks,
events, condition variables, and semaphores.
@@ -4935,7 +4935,7 @@
By default, informational and debugging messages are suppressed and the
output is sent to standard error. Other output options include routing
messages through email, datagrams, sockets, or to an HTTP Server. New
-filters select different routing based on message priority: DEBUG,
+filters can select different routing based on message priority: DEBUG,
INFO, WARNING, ERROR, and CRITICAL.
The logging system can be configured directly from Python or can be
@@ -4967,12 +4967,12 @@
... def __repr__(self):
... return str(self.value)
...
- >>> a = A(10) # create a reference
+ >>> a = A(10) # create a reference
>>> d = weakref.WeakValueDictionary()
>>> d['primary'] = a # does not create a reference
- >>> d['primary'] # fetch the object if it is still alive
+ >>> d['primary'] # fetch the object if it is still alive
10
- >>> del a # remove the one reference
+ >>> del a # remove the one reference
>>> gc.collect() # run garbage collection right away
0
>>> d['primary'] # entry was automatically removed
@@ -5056,6 +5056,62 @@
\end{verbatim}
+\section{Tools for Working with Decimal Floating Point\label{decimal-fp}}
+
+The \module{decimal} module, offers a \class{Decimal} data type for
+decimal floating point arithmetic. Compared to the built-in \class{float}
+type implemented with binary floating point, the new class is especially
+useful for financial applications and other uses which require exact
+decimal representation, control over precision, control over rounding
+to meet legal or regulatory requirements, tracking of significant
+decimal places, or for applications where the user expects the results
+to match hand calculations done as taught in school.
+
+For example, calculating a 5% tax on a 70 cent phone charge gives
+different results in decimal floating point and binary floating point
+with the difference being significant when rounding to the nearest
+cent:
+
+\begin{verbatim}
+>>> from decimal import *
+>>> Decimal('0.70') * Decimal('1.05')
+Decimal("0.7350")
+>>> .70 * 1.05
+0.73499999999999999
+\end{verbatim}
+
+Note that the \class{Decimal} result keeps a trailing zero, automatically
+inferring four place significance from two digit mulitiplicands. Decimal
+reproduces mathematics as done by hand and avoids issues that can arise
+when binary floating point cannot exactly represent decimal quantities.
+
+Exact representation enables the \class{Decimal} class to perform
+modulo calculations and equality tests that are unsuitable for binary
+floating point:
+
+\begin{verbatim}
+>>> Decimal('1.00') % Decimal('.10')
+Decimal("0.00")
+>>> 1.00 % 0.10
+0.09999999999999995
+
+>>> sum([Decimal('0.1')]*10) == Decimal('1.0')
+True
+>>> sum([0.1]*10) == 1.0
+False
+\end{verbatim}
+
+The \module{decimal} module also allows arbitrarily large precisions to be
+set for calculation:
+
+\begin{verbatim}
+>>> getcontext().prec = 36
+>>> Decimal(1) / Decimal(7)
+Decimal("0.142857142857142857142857142857142857")
+\end{verbatim}
+
+
+
\chapter{What Now? \label{whatNow}}
Reading this tutorial has probably reinforced your interest in using