add user-modifiable recursion_limit

ceval.c:
    define recurion_limit (static), default value is 2500
    define Py_GetRecursionLimit and Py_SetRecursionLimit
    raise RuntimeError if limit is exceeded
PC/config.h:
    remove plat-specific definition
sysmodule.c:
    add sys.(get|set)recursionlimit

1 files changed, 18 insertions, 0 deletions

diff --git a/Doc/lib/libsys.tex b/Doc/lib/libsys.tex
index bbea623..ac28e6f 100644
--- a/Doc/lib/libsys.tex
+++ b/Doc/lib/libsys.tex
@@ -148,6 +148,13 @@ generally one higher than you might expect, because it includes the
 (temporary) reference as an argument to \function{getrefcount()}.
 \end{funcdesc}
 
+\begin{funcdesc}{getrecursionlimit}{}
+Return the current value of the recursion limit, the maximum depth of
+the Python interpreter stack.  This limit prevents infinite recursion
+from causing an overflow of the C stack and crashing Python.  It can
+be set by \function{setrecursionlimit}.
+\end{funcdesc}
+
 \begin{datadesc}{hexversion}
 The version number encoded as a single integer.  This is guaranteed to
 increase with each version, including proper support for
@@ -275,6 +282,17 @@ maximizing responsiveness as well as overhead.
 \index{profile function}
 \index{profiler}
 
+\begin{funcdesc}{setrecursionlimit}{limit}
+Set the maximum depth of the Python interpreter stack to \var{limit}.
+This limit prevents infinite recursion from causing an overflow of the
+C stack and crashing Python.  
+
+The highest possible limit is platform-dependent.  A user may need to
+set the limit higher when she has a program that requires deep
+recursion and a platform that supports a higher limit.  This should be
+done with care, because a too-high limit can lead to a crash.
+\edn{funcdesc}
+
 \begin{funcdesc}{settrace}{tracefunc}
   Set the system's trace function, which allows you to implement a
   Python source code debugger in Python.  See section ``How It Works''