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author | Greg Ward <gward@python.net> | 2002-06-29 02:38:50 (GMT) |
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committer | Greg Ward <gward@python.net> | 2002-06-29 02:38:50 (GMT) |
commit | ae64f3adcd4b9f11710520ad47075930e175cd1d (patch) | |
tree | 6ac2cea8b9ab219e16176de04159aa77379ad377 /Doc/lib | |
parent | 8b46c71d5b5444f9554008ebb2aa808f4f48e5e1 (diff) | |
download | cpython-ae64f3adcd4b9f11710520ad47075930e175cd1d.zip cpython-ae64f3adcd4b9f11710520ad47075930e175cd1d.tar.gz cpython-ae64f3adcd4b9f11710520ad47075930e175cd1d.tar.bz2 |
Add documentation for new textwrap module.
Diffstat (limited to 'Doc/lib')
-rw-r--r-- | Doc/lib/lib.tex | 1 | ||||
-rw-r--r-- | Doc/lib/libtextwrap.tex | 141 |
2 files changed, 142 insertions, 0 deletions
diff --git a/Doc/lib/lib.tex b/Doc/lib/lib.tex index f285dda..70b1c93 100644 --- a/Doc/lib/lib.tex +++ b/Doc/lib/lib.tex @@ -107,6 +107,7 @@ and how to embed it in other applications. \input{libdifflib} \input{libfpformat} \input{libstringio} +\input{libtextwrap} \input{libcodecs} \input{libunicodedata} diff --git a/Doc/lib/libtextwrap.tex b/Doc/lib/libtextwrap.tex new file mode 100644 index 0000000..a4924e7 --- /dev/null +++ b/Doc/lib/libtextwrap.tex @@ -0,0 +1,141 @@ +\section{\module{textwrap} --- + Text wrapping and filling} + +\declaremodule{standard}{textwrap} +\modulesynopsis{Text wrapping and filling} +\moduleauthor{Greg Ward}{gward@python.net} +\sectionauthor{Greg Ward}{gward@python.net} + +\versionadded{2.3} + +The \module{textwrap} module provides two convenience functions, +\function{wrap()} and \function{fill()}, as well as +\class{TextWrapper}, the class that does all the work. If you're just +wrapping or filling one or two text strings, the convenience functions +should be good enough; otherwise, you should use an instance of +\class{TextWrapper} for efficiency. + +\begin{funcdesc}{wrap}{text, width=70, **kwargs} +Wraps the single paragraph in \var{text} (a string) so every line is at +most \var{width} characters long. Returns a list of output lines, +without final newlines. + +Optional keyword arguments correspond to the instance attributes of +\class{TextWrapper}, documented below. +\end{funcdesc} + +\begin{funcdesc}{fill}{text, width=70, **kwargs} +Wraps the single paragraph in \var{text}, and returns a single string +containing the wrapped paragraph. \function{fill()} is shorthand for +\begin{verbatim} +"\n".join(wrap(text, ...)) +\end{verbatim} + +In particular, \function{fill()} accepts exactly the same keyword +arguments as \function{wrap()}. +\end{funcdesc} + +Both \function{wrap()} and \function{fill()} work by creating a +\class{TextWrapper} instance and calling a single method on it. That +instance is not reused, so for applications that wrap/fill many text +strings, it will be more efficient for you to create your own +\class{TextWrapper} object. + +% XXX how to typeset long argument lists? this just spills off +% the edge of the page, with or without \\ delimiters +\begin{classdesc}{TextWrapper}{width=70, \\ + initial_indent="", \\ + subsequent_indent="", \\ + expand_tabs=True, \\ + replace_whitespace=True, \\ + fix_sentence_endings=False, \\ + break_long_words=True} + +Each keyword argument to the constructor corresponds to an instance +attribute, so for example +\begin{verbatim} +wrapper = TextWrapper(initial_indent="* ") +\end{verbatim} +is the same as +\begin{verbatim} +wrapper = TextWrapper() +wrapper.initial_indent = "* " +\end{verbatim} + +You can re-use the same \class{TextWrapper} object many times, and you +can change any of its options through direct assignment to instance +attributes between uses. The effects of the instance attributes are as +follows: + +\begin{memberdesc}[bool]{expand_tabs} +If true (the default), then all tab characters in \var{text} will be +expanded to spaces using the \method{expand_tabs()} method of +\var{text}. +\end{memberdesc} + +\begin{memberdesc}[bool]{replace_whitespace} +If true (the default), each whitespace character (as defined by +\var{string.whitespace}) remaining after tab expansion will be replaced +by a single space. \note{If \var{expand_tabs} is false and +\var{replace_whitespace} is true, each tab character will be replaced by +a single space, which is \emph{not} the same as tab expansion.} +\end{memberdesc} + +% XXX how to typeset the empty string? this looks awful, and "" is worse. +\begin{memberdesc}[string]{initial_indent} +(default: '') String that will be prepended to the first line of wrapped +output. Counts towards the length of the first line. +\end{memberdesc} + +\begin{memberdesc}[string]{subsequent_indent} +(default: '') String that will be prepended to all lines of wrapped +output except the first. Counts towards the length of each line except +the first. +\end{memberdesc} + +\begin{memberdesc}[bool]{fix_sentence_endings} +(default: false) If true, \class{TextWrapper} attempts to detect +sentence endings and ensure that sentences are always separated by +exactly two spaces. This is generally desired for text in a monospaced +font. However, the sentence detection algorithm is imperfect: it +assumes that a sentence ending consists of a lowercase letter followed +by one of \character{.}, +\character{!}, or \character{?}, possibly followed by one of +\character{"} or \character{'}. One problem with this is algoritm is +that it is unable to detect the difference between ``Dr.'' in +\begin{verbatim} +[...] Dr. Frankenstein's monster [...] +\end{verbatim} +and ``Spot.'' in +\begin{verbatim} +[...] See Spot. See Spot run [...] +\end{verbatim} +Furthermore, since it relies on \var{string.lowercase} for the +definition of ``lowercase letter'', it is specific to English-language +texts. Thus, \var{fix_sentence_endings} is false by default. +\end{memberdesc} + +\begin{memberdesc}[bool]{break_long_words} +If true (the default), then words longer than \var{width} will be broken +in order to ensure that no lines are longer than \var{width}. If it is +false, long words will not be broken, and some lines may be longer than +\var{width}. (Long words will be put on a line by themselves, in order +to minimize the amount by which \var{width} is exceeded.) +\end{memberdesc} + +\class{TextWrapper} also provides two public methods, analogous to the +module-level convenience functions: + +\begin{methoddesc}{wrap}{text} +Wraps the single paragraph in \var{text} (a string) so every line is at +most \var{width} characters long. All wrapping options are taken from +instance attributes of the \class{TextWrapper} instance. Returns a list +of output lines, without final newlines. +\end{methoddesc} + +\begin{methoddesc}{fill}{text} +Wraps the single paragraph in \var{text}, and returns a single string +containing the wrapped paragraph. +\end{methoddesc} + +\end{classdesc} |