Merge part of the trunk changes into the p3yk branch. This merges fro…

…m 43030

(branch-creation time) up to 43067. 43068 and 43069 contain a little
swapping action between re.py and sre.py, and this mightily confuses svn
merge, so later changes are going in separately.

This merge should break no additional tests.

The last-merged revision is going in a 'last_merge' property on '.' (the
branch directory.) Arbitrarily chosen, really; if there's a BCP for this, I
couldn't find it, but we can easily change it afterwards ;)

Doc/lib/libcodecs.tex

@@ -24,16 +24,37 @@ \section{\module{codecs} ---
 \begin{funcdesc}{register}{search_function}
 Register a codec search function. Search functions are expected to
 take one argument, the encoding name in all lower case letters, and
-return a tuple of functions \code{(\var{encoder}, \var{decoder}, \var{stream_reader},
-\var{stream_writer})} taking the following arguments:
+return a \class{CodecInfo} object having the following attributes:
+
+\begin{itemize}
+  \item \code{name} The name of the encoding;
+  \item \code{encoder} The stateless encoding function;
+  \item \code{decoder} The stateless decoding function;
+  \item \code{incrementalencoder} An incremental encoder class or factory function;
+  \item \code{incrementaldecoder} An incremental decoder class or factory function;
+  \item \code{streamwriter} A stream writer class or factory function;
+  \item \code{streamreader} A stream reader class or factory function.
+\end{itemize}
+
+The various functions or classes take the following arguments:
 
   \var{encoder} and \var{decoder}: These must be functions or methods
   which have the same interface as the
   \method{encode()}/\method{decode()} methods of Codec instances (see
   Codec Interface). The functions/methods are expected to work in a
   stateless mode.
 
-  \var{stream_reader} and \var{stream_writer}: These have to be
+  \var{incrementalencoder} and \var{incrementalencoder}: These have to be
+  factory functions providing the following interface:
+
+        \code{factory(\var{errors}='strict')}
+
+  The factory functions must return objects providing the interfaces
+  defined by the base classes \class{IncrementalEncoder} and
+  \class{IncrementalEncoder}, respectively. Incremental codecs can maintain
+  state.
+
+  \var{streamreader} and \var{streamwriter}: These have to be
   factory functions providing the following interface:
 
         \code{factory(\var{stream}, \var{errors}='strict')}
@@ -58,13 +79,13 @@ \section{\module{codecs} ---
 \end{funcdesc}
 
 \begin{funcdesc}{lookup}{encoding}
-Looks up a codec tuple in the Python codec registry and returns the
-function tuple as defined above.
+Looks up the codec info in the Python codec registry and returns a
+\class{CodecInfo} object as defined above.
 
 Encodings are first looked up in the registry's cache. If not found,
-the list of registered search functions is scanned. If no codecs tuple
-is found, a \exception{LookupError} is raised. Otherwise, the codecs
-tuple is stored in the cache and returned to the caller.
+the list of registered search functions is scanned. If no \class{CodecInfo}
+object is found, a \exception{LookupError} is raised. Otherwise, the
+\class{CodecInfo} object is stored in the cache and returned to the caller.
 \end{funcdesc}
 
 To simplify access to the various codecs, the module provides these
@@ -85,6 +106,22 @@ \section{\module{codecs} ---
 Raises a \exception{LookupError} in case the encoding cannot be found.
 \end{funcdesc}
 
+\begin{funcdesc}{getincrementalencoder}{encoding}
+Lookup up the codec for the given encoding and return its incremental encoder
+class or factory function.
+
+Raises a \exception{LookupError} in case the encoding cannot be found or the
+codec doesn't support an incremental encoder.
+\end{funcdesc}
+
+\begin{funcdesc}{getincrementaldecoder}{encoding}
+Lookup up the codec for the given encoding and return its incremental decoder
+class or factory function.
+
+Raises a \exception{LookupError} in case the encoding cannot be found or the
+codec doesn't support an incremental decoder.
+\end{funcdesc}
+
 \begin{funcdesc}{getreader}{encoding}
 Lookup up the codec for the given encoding and return its StreamReader
 class or factory function.
@@ -188,6 +225,18 @@ \section{\module{codecs} ---
 an encoding error occurs.
 \end{funcdesc}
 
+\begin{funcdesc}{iterencode}{iterable, encoding\optional{, errors}}
+Uses an incremental encoder to iteratively encode the input provided by
+\var{iterable}. This function is a generator. \var{errors} (as well as
+any other keyword argument) is passed through to the incremental encoder.
+\end{funcdesc}
+
+\begin{funcdesc}{iterdecode}{iterable, encoding\optional{, errors}}
+Uses an incremental decoder to iteratively decode the input provided by
+\var{iterable}. This function is a generator. \var{errors} (as well as
+any other keyword argument) is passed through to the incremental encoder.
+\end{funcdesc}
+
 The module also provides the following constants which are useful
 for reading and writing to platform dependent files:
 
@@ -292,6 +341,109 @@ \subsubsection{Codec Objects \label{codec-objects}}
   empty object of the output object type in this situation.
 \end{methoddesc}
 
+The \class{IncrementalEncoder} and \class{IncrementalDecoder} classes provide
+the basic interface for incremental encoding and decoding. Encoding/decoding the
+input isn't done with one call to the stateless encoder/decoder function,
+but with multiple calls to the \method{encode}/\method{decode} method of the
+incremental encoder/decoder. The incremental encoder/decoder keeps track of
+the encoding/decoding process during method calls.
+
+The joined output of calls to the \method{encode}/\method{decode} method is the
+same as if the all single inputs where joined into one, and this input was
+encoded/decoded with the stateless encoder/decoder.
+
+
+\subsubsection{IncrementalEncoder Objects \label{incremental-encoder-objects}}
+
+The \class{IncrementalEncoder} class is used for encoding an input in multiple
+steps. It defines the following methods which every incremental encoder must
+define in order to be compatible to the Python codec registry.
+
+\begin{classdesc}{IncrementalEncoder}{\optional{errors}}
+  Constructor for a \class{IncrementalEncoder} instance.
+
+  All incremental encoders must provide this constructor interface. They are
+  free to add additional keyword arguments, but only the ones defined
+  here are used by the Python codec registry.
+
+  The \class{IncrementalEncoder} may implement different error handling
+  schemes by providing the \var{errors} keyword argument. These
+  parameters are predefined:
+
+  \begin{itemize}
+    \item \code{'strict'} Raise \exception{ValueError} (or a subclass);
+                          this is the default.
+    \item \code{'ignore'} Ignore the character and continue with the next.
+    \item \code{'replace'} Replace with a suitable replacement character
+    \item \code{'xmlcharrefreplace'} Replace with the appropriate XML
+                     character reference
+    \item \code{'backslashreplace'} Replace with backslashed escape sequences.
+  \end{itemize}
+
+  The \var{errors} argument will be assigned to an attribute of the
+  same name. Assigning to this attribute makes it possible to switch
+  between different error handling strategies during the lifetime
+  of the \class{IncrementalEncoder} object.
+
+  The set of allowed values for the \var{errors} argument can
+  be extended with \function{register_error()}.
+\end{classdesc}
+
+\begin{methoddesc}{encode}{object\optional{, final}}
+  Encodes \var{object} (taking the current state of the encoder into account)
+  and returns the resulting encoded object. If this is the last call to
+  \method{encode} \var{final} must be true (the default is false).
+\end{methoddesc}
+
+\begin{methoddesc}{reset}{}
+  Reset the encoder to the initial state.
+\end{methoddesc}
+
+
+\subsubsection{IncrementalDecoder Objects \label{incremental-decoder-objects}}
+
+The \class{IncrementalDecoder} class is used for decoding an input in multiple
+steps. It defines the following methods which every incremental decoder must
+define in order to be compatible to the Python codec registry.
+
+\begin{classdesc}{IncrementalDecoder}{\optional{errors}}
+  Constructor for a \class{IncrementalDecoder} instance.
+
+  All incremental decoders must provide this constructor interface. They are
+  free to add additional keyword arguments, but only the ones defined
+  here are used by the Python codec registry.
+
+  The \class{IncrementalDecoder} may implement different error handling
+  schemes by providing the \var{errors} keyword argument. These
+  parameters are predefined:
+
+  \begin{itemize}
+    \item \code{'strict'} Raise \exception{ValueError} (or a subclass);
+                          this is the default.
+    \item \code{'ignore'} Ignore the character and continue with the next.
+    \item \code{'replace'} Replace with a suitable replacement character.
+  \end{itemize}
+
+  The \var{errors} argument will be assigned to an attribute of the
+  same name. Assigning to this attribute makes it possible to switch
+  between different error handling strategies during the lifetime
+  of the \class{IncrementalEncoder} object.
+
+  The set of allowed values for the \var{errors} argument can
+  be extended with \function{register_error()}.
+\end{classdesc}
+
+\begin{methoddesc}{decode}{object\optional{, final}}
+  Decodes \var{object} (taking the current state of the decoder into account)
+  and returns the resulting decoded object. If this is the last call to
+  \method{decode} \var{final} must be true (the default is false).
+\end{methoddesc}
+
+\begin{methoddesc}{reset}{}
+  Reset the decoder to the initial state.
+\end{methoddesc}
+
+
 The \class{StreamWriter} and \class{StreamReader} classes provide
 generic working interfaces which can be used to implement new
 encodings submodules very easily. See \module{encodings.utf_8} for an

Doc/whatsnew/whatsnew25.tex

@@ -209,6 +209,12 @@ \section{PEP 328: Absolute and Relative Imports}
 % XXX write this
 
 
+%======================================================================
+\section{PEP 338: Executing Modules as Scripts}
+
+% XXX write this
+
+
 %======================================================================
 \section{PEP 341: Unified try/except/finally}
 

Include/codecs.h

@@ -29,15 +29,15 @@ PyAPI_FUNC(int) PyCodec_Register(
 
 /* Codec register lookup API.
 
-   Looks up the given encoding and returns a tuple (encoder, decoder,
-   stream reader, stream writer) of functions which implement the
-   different aspects of processing the encoding.
+   Looks up the given encoding and returns a CodecInfo object with
+   function attributes which implement the different aspects of
+   processing the encoding.
 
    The encoding string is looked up converted to all lower-case
    characters. This makes encodings looked up through this mechanism
    effectively case-insensitive.
 
-   If no codec is found, a KeyError is set and NULL returned. 
+   If no codec is found, a KeyError is set and NULL returned.
 
    As side effect, this tries to load the encodings package, if not
    yet done. This is part of the lazy load strategy for the encodings
@@ -101,6 +101,20 @@ PyAPI_FUNC(PyObject *) PyCodec_Decoder(
        const char *encoding
        );
 
+/* Get a IncrementalEncoder object for the given encoding. */
+
+PyAPI_FUNC(PyObject *) PyCodec_IncrementalEncoder(
+       const char *encoding,
+       const char *errors
+       );
+
+/* Get a IncrementalDecoder object function for the given encoding. */
+
+PyAPI_FUNC(PyObject *) PyCodec_IncrementalDecoder(
+       const char *encoding,
+       const char *errors
+       );
+
 /* Get a StreamReader factory function for the given encoding. */
 
 PyAPI_FUNC(PyObject *) PyCodec_StreamReader(

Lib/StringIO.py

@@ -72,8 +72,7 @@ def next(self):
         method is called repeatedly. This method returns the next input line,
         or raises StopIteration when EOF is hit.
         """
-        if self.closed:
-            raise StopIteration
+        _complain_ifclosed(self.closed)
         r = self.readline()
         if not r:
             raise StopIteration