title: Python pdb -- how to change the default lines listed by "l" command?
body: <p>I'm experimenting with debugging my python from the raw pdb program rather than running pdb though emacs (which tracks the current line with a marker in the text display of the code).  It's slightly annoying that the list command l in pdb only displays a few lines of code, I would rather have it fill my terminal with all the code of the current function up to the current line.   </p>
  
  <p>I know I can do this manually by looking at the line numbers are typing l 50,100 (where 100 is the current line) but this is time consuming and I'd like to set this up to work automatically.  </p>
  
  <p>I wonder if there is a way to define a pdb command to do this?   I'm guessing it would need to (1) access the number of the current line, N; then (2) execute "l N-50, N".  I've searched around a lot but can't find anyone who has done this before.  Perhaps there is a way to access the pdb module's own internals to get the line number?  </p>
  
  <p>(Or a roundabout way would be to write something that calls list once, parses the output to extract the current line, then executes a new list command, I wonder if anyone has done this already?   Is this how IDEs manage to get the current line information from pdb or are they using its internals I wonder?)</p>