This is Richie Hindle's patch

[ 643835 ] Set Next Statement for Python debuggers

with a few tweaks by me: adding an unsigned or two, mentioning that
not all jumps are allowed in the doc for pdb, adding a NEWS item and
a note to whatsnew, and AuCTeX doing something cosmetic to libpdb.tex.

3 files changed, 24 insertions, 10 deletions

diff --git a/Doc/lib/libpdb.tex b/Doc/lib/libpdb.tex
index f8417b8..bf779fe 100644
--- a/Doc/lib/libpdb.tex
+++ b/Doc/lib/libpdb.tex
@@ -255,6 +255,16 @@ Continue execution until the current function returns.
 
 Continue execution, only stop when a breakpoint is encountered.
 
+\item[j(ump) \var{lineno}]
+
+Set the next line that will be executed.  Only available in the
+bottom-most frame.  This lets you jump back and execute code
+again, or jump forward to skip code that you don't want to run.
+
+It should be noted that not all jumps are allowed -- for instance it
+it not possible to jump into the middle of a for loop or out of a
+finally clause.
+
 \item[l(ist) \optional{\var{first\optional{, last}}}]
 
 List source code for the current file.  Without arguments, list 11
@@ -303,7 +313,7 @@ alias pi for k in %1.__dict__.keys(): print "%1.",k,"=",%1.__dict__[k]
 #Print instance variables in self
 alias ps pi self
 \end{verbatim}
-		
+                
 \item[unalias \var{name}]
 
 Deletes the specified alias.
diff --git a/Doc/ref/ref3.tex b/Doc/ref/ref3.tex
index eb1d658..605ed55 100644
--- a/Doc/ref/ref3.tex
+++ b/Doc/ref/ref3.tex
@@ -812,8 +812,7 @@ frame; \member{f_locals} is the dictionary used to look up local
 variables; \member{f_globals} is used for global variables;
 \member{f_builtins} is used for built-in (intrinsic) names;
 \member{f_restricted} is a flag indicating whether the function is
-executing in restricted execution mode;
-\member{f_lineno} gives the line number and \member{f_lasti} gives the
+executing in restricted execution mode; \member{f_lasti} gives the
 precise instruction (this is an index into the bytecode string of
 the code object).
 \withsubitem{(frame attribute)}{
@@ -821,7 +820,6 @@ the code object).
   \ttindex{f_code}
   \ttindex{f_globals}
   \ttindex{f_locals}
-  \ttindex{f_lineno}
   \ttindex{f_lasti}
   \ttindex{f_builtins}
   \ttindex{f_restricted}}
@@ -830,12 +828,16 @@ Special writable attributes: \member{f_trace}, if not \code{None}, is a
 function called at the start of each source code line (this is used by
 the debugger); \member{f_exc_type}, \member{f_exc_value},
 \member{f_exc_traceback} represent the most recent exception caught in
-this frame.
+this frame; \member{f_lineno} is the current line number of the frame
+--- writing to this from within a trace function jumps to the given line
+(only for the bottom-most frame).  A debugger can implement a Jump
+command (aka Set Next Statement) by writing to f_lineno.
 \withsubitem{(frame attribute)}{
   \ttindex{f_trace}
   \ttindex{f_exc_type}
   \ttindex{f_exc_value}
-  \ttindex{f_exc_traceback}}
+  \ttindex{f_exc_traceback}
+  \ttindex{f_lineno}}
 
 \item[Traceback objects] \label{traceback}
 Traceback objects represent a stack trace of an exception.  A
diff --git a/Doc/whatsnew/whatsnew23.tex b/Doc/whatsnew/whatsnew23.tex
index 39b7c70..ee8d644 100644
--- a/Doc/whatsnew/whatsnew23.tex
+++ b/Doc/whatsnew/whatsnew23.tex
@@ -12,6 +12,8 @@
 
 % MacOS framework-related changes (section of its own, probably)
 
+% the new set-next-statement functionality of pdb (SF #643835)
+
 %\section{Introduction \label{intro}}
 
 {\large This article is a draft, and is currently up to date for some
@@ -1201,13 +1203,13 @@ For example:
 
 \begin{verbatim}
 >>> days = ['Mo', 'Tu', 'We', 'Th', 'Fr', 'St', 'Sn']
->>> random.sample(days, 3)	# Choose 3 elements
+>>> random.sample(days, 3)      # Choose 3 elements
 ['St', 'Sn', 'Th']
->>> random.sample(days, 7)	# Choose 7 elements
+>>> random.sample(days, 7)      # Choose 7 elements
 ['Tu', 'Th', 'Mo', 'We', 'St', 'Fr', 'Sn']
->>> random.sample(days, 7)	# Choose 7 again
+>>> random.sample(days, 7)      # Choose 7 again
 ['We', 'Mo', 'Sn', 'Fr', 'Tu', 'St', 'Th']
->>> random.sample(days, 8)	# Can't choose eight
+>>> random.sample(days, 8)      # Can't choose eight
 Traceback (most recent call last):
   File "<stdin>", line 1, in ?
   File "random.py", line 414, in sample