Arbitrary call stack access for external debuggers changeset.

[John Swensen]

On Mar 3, 2008, at 9:48 PM, Ryan Rusaw wrote:

> I sent in this patch in prior to the 3.0.0 release, but it never made
> it in prior to the switch to mercurial.
>
> 2008-03-03  Ryan Rusaw  <rrusaw at gmail.com>
>
> 	* top_lev.h: Replace internal std::list with stl::deque in
> 	octave_call_stack to allow access to elements by position
> 	index via element_at () call.
> 	* top_lev.cc: Implement new element_at () call for updated
> 	octave_call_stack class
> 	* pt-stmt.h: Declare new tree_statement_stack class modelled
> 	after octave_call_stack class
> 	* pt-stmt.cc: Remove curr_statement and curr_caller_statement,
> 	and implement tree_statement_stack class to allow call stack
> 	statements to to be accessed by depth index.
> 	* error.cc: Replace references to curr_statement to
> 	tree_statement_stack::current ()
> 	* input.cc: Replace references to curr_statement to
> 	tree_statement_stack::current ()
> 	* ov-usr-func.cc: Remove references to curr_statement and
> 	curr_caller_statement
> <changeset.txt>

I have been working a bit lately on making the debugger act more like  
Matlab in terms of the command line functionality and was wondering if  
you would give a quick synopsis of what this patch does.  I looked  
through all the changes, but don't know enough about how the parser,  
tree represenation of a file,  and debugger interact to fully  
understand it.

John Swensen