In pdb how do you reset the list (l) command line count?

Question

From PDB

(Pdb) help l
l(ist) [first [,last]]
  List source code for the current file.
  Without arguments, list 11 lines around the current line
  or continue the previous listing.
  With one argument, list 11 lines starting at that line.
  With two arguments, list the given range;
  if the second argument is less than the first, it is a count.

The "continue the previous listing" feature is really nice, but how do you turn it off?

Answer 1

I don't think there is a way to turn it off. It's annoyed me enough that once I went looking in the pdb source to see if there was an undocumented syntax, but I didn't find any.

There really needs to be a syntax that means, "List the lines near the current execution pointer."

Answer 2

You could monkey patch it for the behavior you want. For example, here is a full script which adds a "reset_list" or "rl" command to pdb:

import pdb

def Pdb_reset_list(self, arg):
    self.lineno = None
    print >>self.stdout, "Reset list position."
pdb.Pdb.do_reset = Pdb_reset_list
pdb.Pdb.do_rl = Pdb_reset_list

a = 1
b = 2

pdb.set_trace()

print a, b

One could conceivably monkey patch the standard list command to not retain the lineno history.

edit: And here is such a patch:

import pdb
Pdb = pdb.Pdb

Pdb._do_list = Pdb.do_list
def pdb_list_wrapper(self, arg):
    if arg.strip().lower() in ('r', 'reset', 'c', 'current'):
        self.lineno = None
        arg = ''
    self._do_list(arg)
Pdb.do_list = Pdb.do_l = pdb_list_wrapper

a = 1
b = 2

pdb.set_trace()

print a, b

Answer 3

If you use epdb1 instead of pdb, you can use "l" to go forward like in pdb, but then "l." goes back to the current line number, and "l-" goes backwards through the file. You can also use until # to continue until a given line. Epdb offers a bunch of other niceties too.