Re: improving error messages?

[John W. Eaton]

On 21-Oct-2009, Jaroslav Hajek wrote:

| On Wed, Oct 21, 2009 at 12:48 PM, Søren Hauberg <address@hidden> wrote:
| > ons, 21 10 2009 kl. 12:38 +0200, skrev Jaroslav Hajek:
| >> I ended up with the attached patch. This seems to mostly solve my problems:
| >>
| >> octave:1> cellslices (1:3, 1, 4)
| >> error: cellslices: A(I): Index exceeds matrix dimension.
| >> octave:1> any(1, 1.5)
| >> error: any: conversion of 1.5 to int value failed
| >> error: any: expecting dimension argument to be an integer
| >>
| >> I know this is no candidate for the best software design award, but it
| >> works and is a relatively harmless change...
| >>
| >> Comments?
| >
| > Funny! I was thinking about the same problem just a few days ago, and I
| > arrived at the same solution. One question, though:
| >
| > Let's say I'm developing a function 'A' that calls a bunch of other
| > functions, i.e.
| >
| >  function A ()
| >    ...
| >    B ();
| >    ...
| >  endfunction
| >
| > what then happens if 'B' raises an error? Will I then get an error
| > message from 'A' instead? This could potentially make it harder to
| > develop functions or am I missing something?
| >
| > Søren
| >
| 
| No, you'll see a message from the innermost function that raised the
| error, be it B or something else. And it only applies to errors
| originating from liboctave exceptions (which generally have no way of
| knowing who called them) or those generated by the C++ function
| error_with_cfn (or error_with_id_cfn). So most user-generated errors
| are unaffected.

I think I'd rather not have to remember when it is appropriate to call
error_with_cfn.  Maybe it would be better if we changed things so that
the error function always reported the calling function information,
and then changed our style to not include the function name as an
error message prefix?

jwe