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authorFred Drake <fdrake@acm.org>1999-01-27 17:20:33 (GMT)
committerFred Drake <fdrake@acm.org>1999-01-27 17:20:33 (GMT)
commit9d814c6805eefb21ddc8139b35158f0b8103761c (patch)
tree433b188a324cdcb1f32d0f145fc5756e63e2697f /Doc/lib
parentc80baa3365d0c87f419020e3e1f0488d8bae8eb5 (diff)
downloadcpython-9d814c6805eefb21ddc8139b35158f0b8103761c.zip
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Document the repr module. This removes the entire "Code objects and
files, debugger etc." section from "Undocumented Modules"!
Diffstat (limited to 'Doc/lib')
-rw-r--r--Doc/lib/lib.tex1
-rw-r--r--Doc/lib/librepr.tex125
-rw-r--r--Doc/lib/libundoc.tex9
3 files changed, 126 insertions, 9 deletions
diff --git a/Doc/lib/lib.tex b/Doc/lib/lib.tex
index 020a932..87c63c9 100644
--- a/Doc/lib/lib.tex
+++ b/Doc/lib/lib.tex
@@ -88,6 +88,7 @@ add new extensions to Python and how to embed it in other applications.
\input{libkeyword}
\input{libcode}
\input{libpprint}
+\input{librepr}
\input{libpycompile} % really py_compile
\input{libcompileall}
\input{libdis}
diff --git a/Doc/lib/librepr.tex b/Doc/lib/librepr.tex
new file mode 100644
index 0000000..76bf942
--- /dev/null
+++ b/Doc/lib/librepr.tex
@@ -0,0 +1,125 @@
+\section{\module{repr} ---
+ Alternate \function{repr()} implementation.}
+
+\declaremodule{standard}{repr}
+
+
+The \module{repr} module provides a means for producing object
+representations with limits on the size of the resulting strings.
+This is used in the Python debugger and may be useful in other
+contexts as well.
+
+This module provides a class, an instance, and a function:
+
+
+\begin{classdesc}{Repr}{}
+ Class which provides formatting services useful in implementing
+ functions similar to the built-in \function{repr()}; size limits for
+ different object types are added to avoid the generation of
+ representations which are excessively long.
+\end{classdesc}
+
+
+\begin{datadesc}{aRepr}
+ This is an instance of \class{Repr} which is used to provide the
+ \function{repr()} function described below. Changing the attributes
+ of this object will affect the size limits used by \function{repr()}
+ and the Python debugger.
+\end{datadesc}
+
+
+\begin{funcdesc}{repr}{obj}
+ This is the \method{repr()} method of \code{aRepr}. It returns a
+ string similar to that returned by the built-in function of the same
+ name, but with limits on most sizes.
+\end{funcdesc}
+
+
+\subsection{Repr Objects \label{Repr-objects}}
+
+\class{Repr} instances provide several members which can be used to
+provide size limits for the representations of different object types,
+and methods which format specific object types.
+
+
+\begin{memberdesc}{maxlevel}
+ Depth limit on the creation of recursive representations. The
+ default is \code{6}.
+\end{memberdesc}
+
+\begin{memberdesc}{maxdict}
+\memberline{maxlist}
+\memberline{maxtuple}
+ Limits on the number of entries represented for the named object
+ type. The default for \member{maxdict} is \code{4}, for the others,
+ \code{6}.
+\end{memberdesc}
+
+\begin{memberdesc}{maxlong}
+ Maximum number of characters in the representation for a long
+ integer. Digits are dropped from the middle. The default is
+ \code{40}.
+\end{memberdesc}
+
+\begin{memberdesc}{maxstring}
+ Limit on the number of characters in the representation of the
+ string. Note that the ``normal'' representation of the string is
+ used as the character source: if escape sequences are needed in the
+ representation, these may be mangled when the representation is
+ shortened. The default is \code{30}.
+\end{memberdesc}
+
+\begin{memberdesc}{maxother}
+ This limit is used to control the size of object types for which no
+ specific formatting method is available on the \class{Repr} object.
+ It is applied in a similar manner as \member{maxstring}. The
+ default is \code{20}.
+\end{memberdesc}
+
+\begin{methoddesc}{repr}{obj}
+ The equivalent to the built-in \function{repr()} that uses the
+ formatting imposed by the instance.
+\end{methoddesc}
+
+\begin{methoddesc}{repr1}{obj, level}
+ Recursive implementation used by \method{repr()}. This uses the
+ type of \var{obj} to determine which formatting method to call,
+ passing it \var{obj} and \var{level}. The type-specific methods
+ should call \method{repr1()} to perform recursive formatting, with
+ \code{\var{level} - 1} for the value of \var{level} in the recursive
+ call.
+\end{methoddesc}
+
+\begin{methoddescni}{repr_\var{type}}{obj, level}
+ Formatting methods for specific types are implemented as methods
+ with a name based on the type name. In the method name, \var{type}
+ is replaced by
+ \code{string.join(string.split(type(\var{obj}).__name__, '_')}.
+ Dispatch to these methods is handled by \method{repr1()}.
+ Type-specific methods which need to recursively format a value
+ should call \samp{self.repr1(\var{subobj}, \var{level} - 1)}.
+\end{methoddescni}
+
+
+\subsection{Subclassing Repr Objects \label{subclassing-reprs}}
+
+The use of dynamic dispatching by \method{Repr.repr1()} allows
+subclasses of \class{Repr} to add support for additional built-in
+object types or to modify the handling of types already supported.
+This example shows how special support for file objects could be
+added:
+
+\begin{verbatim}
+import repr
+import sys
+
+class MyRepr(repr.Repr):
+ def repr_file(self, obj, level):
+ if obj.name in ['<stdin>', '<stdout>', '<stderr>']:
+ return obj.name
+ else:
+ return `obj`
+
+aRepr = MyRepr()
+print aRepr.repr(sys.stdin) # prints '<stdin>'
+\end{verbatim}
diff --git a/Doc/lib/libundoc.tex b/Doc/lib/libundoc.tex
index bb7274d..d60abc0 100644
--- a/Doc/lib/libundoc.tex
+++ b/Doc/lib/libundoc.tex
@@ -116,15 +116,6 @@ contains helper code for colorizing Python source code.
\end{description}
-\section{Code objects and files, debugger etc.}
-
-\begin{description}
-\item[repr.py]
---- Redo the `...` (representation) but with limits on most
-sizes (used by pdb)
-\end{description}
-
-
\section{Multimedia}
\begin{description}