Re: Message Id for undefined function

[Ben Abbott]

On Jun 22, 2012, at 11:26 AM, Juan Pablo Carbajal wrote:

> Hi all,
> 
> I just realized that there is no message ID when a function is not
> found in the current path. Example
> 
> octave:184> my_function_loca  % This function doesn't exist
> error: `my_function_loca' undefined near line 184 column 1
> octave:184> [msg id] = lasterr
> msg = `my_function_loca' undefined near line 184 column 1
> id =
> 
> I am trying to write a try-catch block that catches that error. What can I do?
> 
> Thanks
> 
> -- 
> M. Sc. Juan Pablo Carbajal

Juan,

I'm not sure what you're looking to do.  When I save the function below in 
foobar.m and then type "foobar ()" ...

function ret = foobar ()
  try
    fubar ();
  catch
    ret = lasterror;
  end
endfunction

... I get ...

ans =

  scalar structure containing the fields:

    message = `fubar' undefined near line 24 column 5
    identifier = 
    stack =

      scalar structure containing the fields:

        file = /Users/bpabbott/Development/mercurial/octave/foobar.m
        name = foobar
        line =  24
        column =  5
        scope =  2
        context = 0

In Matlab, I see ...

>> foobar ()

ans = 

       message: 'Undefined function or variable 'fubar'.'
    identifier: 'MATLAB:UndefinedFunction'
         stack: [1x1 struct]

I you are looking to have the identifier set (something like 
"Octave:undefindedfunction" ?), then a quick parse of the src directory 
indicates pt-id.cc is where this error is found.

        $ fgrep -n 'undefined near line' *.cc
        pt-id.cc:54:    ::error ("`%s' undefined near line %d column %d",

The function is ...

void
tree_identifier::eval_undefined_error (void)
{
  int l = line ();
  int c = column ();

  maybe_missing_function_hook (name ());
  if (error_state)
    return;

  if (l == -1 && c == -1)
    ::error ("`%s' undefined", name ().c_str ());
  else
    ::error ("`%s' undefined near line %d column %d",
             name ().c_str (), l, c);
}

I'm not familiar with this part of the code, and have no idea where the ID 
might be set.  Anyone?

Ben