[Changeset]: filemarker and fix for 'dbstep in'

[John W. Eaton]

On 25-May-2008, David Bateman wrote:

| The attached changeset fixes a bug my previous debug patch introduced
| and adds the filemarker function that is also useful for debugging. The
| bug was that the "dbstep in" command executed parts of the line
| individually rather than prevent the next breakpoint before the next
| line of executed of the function, as occurs with "dbstep", etc.
| 
| The filemarker command itself is trivial, however it is then used to
| identify subfunctions. Consider that you have a function
| 
| # string 1
| function z = testfun (x)
| # string 2
|   y = 1;
|   z = testfun2 (x, y);
| end
| # string 3
| function z = testfun2 (x, y)
| # string 4
|   z = x + y;
| end
| 
| then filemarker can be used like
| 
| help (["testfun", filemarker, "testfun2"])
| 
| or knowing that filemarker is by default ">", then
| 
| help testfun>testfun2
| 
| gives the same result. Other uses include in dbstop to set a breakpoint
| in a subfunction, for example
| 
| dbstop testfun>testfun2
| 
| set the breakpoint at the first line of the testfun2 subfunction. I also
| adapted the backtrace method so that dbstack gives the name of the
| subfunctions including their parent functions..
| 
| Note that the symbol_table:;find_function method will have to be adapted
| if we ever decide to implement nested functions as matlab stupidly uses
| the filesep character to define the nesting rather than the filemarker
| character. That is, if we have a function like
| 
| function f1
|   function f2
|   end
|   function f3
|   end
| end
| function f2
| end
| 
| then to set breakpoints in each of these functions is done like
| 
| dbstop f1
| dbstop f1>f1/f2
| dbstop f1>f3
| dbstop f1>f2

OK.


| If matlab had used filemarker instead of filesep for the nesting, then
| the current adaptation of symbol_table::find_function would already be
| correct.

It seems like it would be better if we could simply write

  f1/f2

to stop in the nested function and

  f1>f2

to stop in the subfunction.  But whatever.  It doesn't seem that
important.

| Note that I allowed the filemarker character to be set,

OK, but is there really any need to change it?

I applied the changeset.

Thanks,

jwe