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Patch #1215184: FileInput now can be given an opening hook which can

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be used to control how files are opened.
This commit is contained in:
Georg Brandl 2006-02-19 14:57:47 +00:00
parent c029f873cb
commit c98eeede17
4 changed files with 105 additions and 12 deletions
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48
Doc/lib/libfileinput.tex
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@ -43,17 +43,23 @@ It is possible that the last line of a file does not end in a newline
character; lines are returned including the trailing newline when it
is present.
You can control how files are opened by providing an opening hook via the
\var{openhook} parameter to \function{input()} or \class{FileInput()}.
The hook must be a function that takes two arguments, \var{filename}
and \var{mode}, and returns an accordingly opened file-like object.
Two useful hooks are already provided by this module.
The following function is the primary interface of this module:
\begin{funcdesc}{input}{\optional{files\optional{,
inplace\optional{, backup\optional{, mode}}}}}
\begin{funcdesc}{input}{\optional{files\optional{, inplace\optional{,
backup\optional{, mode\optional{, openhook}}}}}}
Create an instance of the \class{FileInput} class. The instance
will be used as global state for the functions of this module, and
is also returned to use during iteration. The parameters to this
function will be passed along to the constructor of the
\class{FileInput} class.
\versionchanged[Added the \var{mode} parameter]{2.5}
\versionchanged[Added the \var{mode} and \var{openhook} parameters]{2.5}
\end{funcdesc}
@ -115,7 +121,8 @@ The class which implements the sequence behavior provided by the
module is available for subclassing as well:
\begin{classdesc}{FileInput}{\optional{files\optional{,
inplace\optional{, backup\optional{, mode}}}}}
inplace\optional{, backup\optional{,
mode\optional{, openhook}}}}}}
Class \class{FileInput} is the implementation; its methods
\method{filename()}, \method{fileno()}, \method{lineno()},
\method{fileline()}, \method{isfirstline()}, \method{isstdin()},
@ -131,7 +138,12 @@ module is available for subclassing as well:
\function{open()}. It must be one of \code{'r'}, \code{'rU'},
\code{'U'} and \code{'rb'}.
\versionchanged[Added the \var{mode} parameter]{2.5}
The \var{openhook}, when given, must be a function that takes two arguments,
\var{filename} and \var{mode}, and returns an accordingly opened
file-like object.
You cannot use \var{inplace} and \var{openhook} together.
\versionchanged[Added the \var{mode} and \var{openhook} parameters]{2.5}
\end{classdesc}
\strong{Optional in-place filtering:} if the keyword argument
@ -148,3 +160,29 @@ filtering is disabled when standard input is read.
\strong{Caveat:} The current implementation does not work for MS-DOS
8+3 filesystems.
The two following opening hooks are provided by this module:
\begin{funcdesc}{hook_compressed}{filename, mode}
Transparently opens files compressed with gzip and bzip2 using
the \module{gzip} and \module{bz2} modules.
Usage example:
\samp{fi = fileinput.FileInput(openhook=fileinput.hook_compressed)}
\versionadded{2.5}
\end{funcdesc}
\begin{funcdesc}{hook_encoded}{encoding}
Returns a hook which opens each file with \function{codecs.open()},
using the given \var{encoding} to read the file.
Usage example:
\samp{fi = fileinput.FileInput(openhook=fileinput.hook_encoded("iso-8859-1"))}
\note{With this hook, \class{FileInput} might return Unicode strings
depending on the specified \var{encoding}.}
\versionadded{2.5}
\end{funcdesc}