[Python-checkins] r51688 - in python/trunk/Doc: lib/libdecimal.tex whatsnew/whatsnew25.tex
raymond.hettinger
python-checkins at python.org
Sat Sep 2 19:07:24 CEST 2006
Author: raymond.hettinger
Date: Sat Sep 2 19:07:23 2006
New Revision: 51688
Modified:
python/trunk/Doc/lib/libdecimal.tex
python/trunk/Doc/whatsnew/whatsnew25.tex
Log:
Fix documentation nits for decimal context managers.
Modified: python/trunk/Doc/lib/libdecimal.tex
==============================================================================
--- python/trunk/Doc/lib/libdecimal.tex (original)
+++ python/trunk/Doc/lib/libdecimal.tex Sat Sep 2 19:07:23 2006
@@ -448,27 +448,23 @@
\begin{funcdesc}{localcontext}{\optional{c}}
Return a context manager that will set the current context for
- the active thread to a copy of \var{c} on entry to the with statement
- and restore the previous context when exiting the with statement. If
+ the active thread to a copy of \var{c} on entry to the with-statement
+ and restore the previous context when exiting the with-statement. If
no context is specified, a copy of the current context is used.
+ \versionadded{2.5}
- For example the following code increases the current decimal precision
+ For example, the following code increases the current decimal precision
by 42 places, performs a calculation, and then automatically restores
the previous context:
\begin{verbatim}
from __future__ import with_statement
import decimal
- with decimal.localcontext() as ctx:
+ with localcontext() as ctx:
ctx.prec = 42 # Perform a high precision calculation
s = calculate_something()
s = +s # Round the final result back to the default precision
\end{verbatim}
-
- The context that is held by the context manager and made active in the
- body of the \keyword{with} statement is a \emph{copy} of the context
- you provide to this function, so modifying its attributes doesn't
- affect anything except that temporary copy.
\end{funcdesc}
New contexts can also be created using the \class{Context} constructor
Modified: python/trunk/Doc/whatsnew/whatsnew25.tex
==============================================================================
--- python/trunk/Doc/whatsnew/whatsnew25.tex (original)
+++ python/trunk/Doc/whatsnew/whatsnew25.tex Sat Sep 2 19:07:23 2006
@@ -685,20 +685,19 @@
The \module{decimal} module's contexts, which encapsulate the desired
precision and rounding characteristics for computations, provide a
-\method{context_manager()} method for getting a context manager:
+\function{localcontext()} function for getting a context manager:
\begin{verbatim}
-import decimal
+from decimal import Decimal, Context, localcontext
# Displays with default precision of 28 digits
-v1 = decimal.Decimal('578')
-print v1.sqrt()
+v = Decimal('578')
+print v.sqrt()
-ctx = decimal.Context(prec=16)
-with ctx.context_manager():
+with localcontext(Context(prec=16)):
# All code in this block uses a precision of 16 digits.
# The original context is restored on exiting the block.
- print v1.sqrt()
+ print v.sqrt()
\end{verbatim}
\subsection{Writing Context Managers\label{context-managers}}
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