From bug-octave-request at bevo dot che dot wisc dot edu  Fri Apr 20 07:30:51 2001
Subject: Re: eval() tramples on __error_text__
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Christoph Spiel <cspiel at hammersmith-consulting dot com>
Cc: bug-octave at bevo dot che dot wisc dot edu
Date: Fri, 20 Apr 2001 07:30:42 -0500

On 20-Apr-2001, Christoph Spiel <cspiel at hammersmith-consulting dot com> wrote:

| Applied your patch.
| 
| Now, '__error_text__' is defined in the catch-string of an eval(), but
| it does not get undefined outside of it.  In fact, '__error_text__'
| cannot be redefined at all.  See line :2>, where the error message
| should report 'b' to be undefined.
| 
| 
|     octave:1> eval("clear a; a;", "et = __error_text__;"); et, __error_text__
|     et = `a' undefined near line 0 column 10
| 
|     __error_text__ = `a' undefined near line 0 column 10
| 
|     octave:2> try clear b; b; catch et = __error_text__; end_try_catch; et
|     et = `a' undefined near line 0 column 10
| 
| 
| For reasons beyond my imagination, the symbol '__error_text__' winds
| up in in 'curr_sym_tab', but bind_builtin_constant() accesses
| 'global_sym_tab'.

Hmm.  This is not the behavior I see with the current CVS sources
(same as 2.1.34 at this point):

  octave:1> eval("clear a; a;", "et = __error_text__;"); et, __error_text__
  et = `a' undefined near line 0 column 10

  __error_text__ = 
  octave:2> try clear b; b; catch et = __error_text__; end_try_catch; et
  et = `b' undefined near line 2 column 14

  octave:3> __error_text__
  __error_text__ = 
  octave:4> who

  *** local user variables:

  et

  *** globally visible user variables:

  __disable_lyap_interface_change_warning__


jwe



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