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Re: Re: immediate abort at error messages

• To: mathgroup at smc.vnet.net
• Subject: [mg55920] Re: [mg55906] Re: [mg55764] immediate abort at error messages
• From: Chris Chiasson <chris.chiasson at gmail.com>
• Date: Sun, 10 Apr 2005 06:54:51 -0400 (EDT)
• References: <200504051010.GAA01066@smc.vnet.net> <200504090756.DAA12432@smc.vnet.net>
• Reply-to: Chris Chiasson <chris.chiasson at gmail.com>
• Sender: owner-wri-mathgroup at wolfram.com

Thank you for this.

On Apr 9, 2005 3:56 AM, Omega Consulting <info at omegaconsultinggroup.com> wrote:
> 
> This is quite a creative trick.
> 
> Unfortunately, it doesn't look like you can use it and get the message.
> $Messages is a list of OutputStreams that any messages are written to.
> If the OutputStream is stdout, then you get the normal message. If it
> is an OutputStream to a file, then it is written to that file. So I
> thought that the following might work, but it doesn't:
> 
> $Messages := {OutputStream["stdout",1], Abort[]}
> 
> Why not? Because $Messages is evaluated *before* the messages are
> actually sent to the streams.
> 
> Still there is another trick we can use, called a trap. A message is
> created whenever the Message function is called. We can redefine this
> function by unprotecting it.
> 
> In[1]:= Unprotect[Message];
> 
> Now we create a global variable to indicate what we want to do with a
> Message. When the variable is True, we want to deviate from the default
> behavior. When False, we want the default behavior (i.e. a message).
> 
> In[2]:= $AbortMessage=True;
> 
> Now we add a definition for when the variable is True. It calls Message
> with the variable set to False (creating a message) and then Aborts.
> 
> In[3]:=
> Message[args___] :=
>   (Block[{$AbortMessage=False},
>      Message[args]
>      ]; Abort[]
>     )/;$AbortMessage
> 
> To be safe we re-protect Message.
> 
> In[4]:= Protect[Message];
> 
> Now we try it.
> 
> In[5]:= (Sin[2,2];Print[2])
> Sin::"argx": "Sin called with 2 arguments; 1 argument is expected.
> More?"
> Out[5]= $Aborted
> 
> ----------------------------------------------
> Omega Consulting
> The final answer to your Mathematica needs.
> http://omegaconsultinggroup.com
> On Apr 5, 2005, at 5:10 AM, Marcus Stollsteimer wrote:
> 
> > Hi group,
> >
> > I recently learned that there is a way to immediately abort
> > when an error occurs in the middle of a cell, so that Mathematica
> > does not try to evaluate the subsequent expressions with
> > possibly bad input:
> >
> > with
> >
> >   $Messages:=Abort[]
> >
> > (see message <2430df44.0411240157.4d06479a at posting.google.com>)
> >
> > but now, when an error occurs, Mathematica aborts without any
> > message...
> > it would be useful to still see the error message,
> > is there a way to do this (display message, then abort)?
> >
> > Best regards,
> > Marcus
> >
> > --
> > Money is better than poverty, if only for financial reasons.
> >    -- W. Allen
> >
> 
> 


-- 
Chris Chiasson
Kettering University
Mechanical Engineering
Graduate Student
1 810 265 3161

• References:
  • immediate abort at error messages
    • From: Marcus Stollsteimer <marcus314@yahoo.com>
  • Re: immediate abort at error messages
    • From: Omega Consulting <info@omegaconsultinggroup.com>