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Can't find where the warning msg is from

Asked by Mindy on 24 Apr 2013

Hi everyone,

I have been receiving a warning message saying 'no regexp for "double"'. According to the warning message showed, it occurred at the line coded like this: notify(obj,event,myinput);

I can't figure out what triggered the warning since it's only the notify function. and myinput is a structure. I also have checked the code that calls notify(obj,event,myinput).

Appreciated if anyone can help!

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Mindy

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4 Answers

Answer by per isakson on 24 Apr 2013
Edited by per isakson on 24 Apr 2013

Matlab fails to provide a meaningsful error message in this situation. It's left to the user to provide a work-around.

Here is a small example of my work-around. It is code from the on-ine help with a bit of error handling added together with code that causes an error: buf = 1; disp( buf(2) ). The trick is: try, overflowHandler_(eventSrc,eventData), catch me, disp(getReport(me)), end

Run

    %%
    sec = setupSEC;
    sec.prop1 = 5;
    sec.prop1 = 15;

returns to the command window

    The value of Prop1 is overflowing!
    It's value was: 5
    It's current value is: 15
    Attempted to access buf(2); index out of bounds because numel(buf)=1.
    Error in overflowHandler>overflowHandler_ (line 13)
        disp( buf(2) )
    Error in overflowHandler (line 3)
            overflowHandler_( eventSrc, eventData )
    Error in SimpleEventClass/set.prop1 (line 14)
                    notify( this,'Overflow',SpecialEventDataClass( org_value ) );  

where

    function    sec = setupSEC
        % Create an object and attach the listener
        sec = SimpleEventClass;
        addlistener( sec, 'Overflow', @overflowHandler )
    end 

and

    classdef    SimpleEventClass < handle
        properties
            prop1 = 0;
        end
        events
            Overflow
        end
        methods
            function    set.prop1( this, value )
                org_value   = this.prop1;
                this.prop1  = value;
                if ( this.prop1 > 10)
                    % Trigger the event using custom event data
                    notify( this, 'Overflow', SpecialEventDataClass( org_value ) );
                end
            end
        end
    end

and

    classdef    SpecialEventDataClass < event.EventData
        properties
            OrgValue = 0;
        end
        methods
            function eventData = SpecialEventDataClass( value )
                eventData.OrgValue = value;
            end
        end
    end

and

    function overflowHandler( eventSrc, eventData )
        try 
            overflowHandler_( eventSrc, eventData )
        catch me 
            disp( getReport( me ) )
        end
    end
    function overflowHandler_( eventSrc, eventData )
        disp('The value of Prop1 is overflowing!')
        disp(['It''s value was: ' num2str( eventData.OrgValue )])
        disp(['It''s current value is: ' num2str( eventSrc.prop1 )])
        buf = 1;
        disp( buf(2) )
    end

I use the same approach with code invoked by a timer. I've found it really helpful. See Debug code invoked by timer

0 Comments

per isakson
Answer by Image Analyst on 24 Apr 2013

First, review this link: http://blogs.mathworks.com/videos/2012/07/03/debugging-in-matlab/. Then step through your code with F10 (step over) and F11 (step into) until you see red text barfed up into the command window. Then you'll know what line it happened on. You can speed past sections of code by setting breakpoints. By the way, did you search your code for regexp?

1 Comment

Daniel on 25 Apr 2013

I am not sure that debugging callbacks in this way is really viable. I am not even sure how the event queue is handled when you are in debug mode. I am pretty sure if timers are involved that you would have a disaster on your hands.

Image Analyst
Answer by Walter Roberson on 24 Apr 2013

What is class(event) ? It needs to be a string and you might get that warning if it was not.

0 Comments

Walter Roberson
Answer by Daniel on 25 Apr 2013

The idea of notify(obj,event,myinput) is that MATLAB sends a signal to all objects that are listening for the event event. You will not find this object/callback by looking at your code in a linear manner. You want to look for where the listener was created. This is usually done with addlistener

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Daniel

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