[Zope3-dev] zope.formlib and displaying invariant errors

[Gary Poster]

On Jul 14, 2005, at 4:50 AM, Jan-Wijbrand Kolman wrote:

> Hello,
>
>
> I'm using zope.formlib (aka zc.page) for rendering (complex) forms.  
> I think this works out great!
>
> Still there's something I cannot really bend my head arround and  
> that's dealing with invariant errors. Hopefully my explanation/ 
> question is not too fuzzy because of that...
>
> I think to understand that, upon form submission, the form update()  
> method takes care of first setting up the (edit or input) widgets,  
> then determining what action should be called, and just before that  
> validating the user input.
>
> The validation of user input might result in errors validation and/ 
> or invariant errors. This list of (both validation and invariant)  
> errors is then set on the form and can be used to display feedback  
> to the user.
>
> I'm actually not using this list of errors on the form for  
> rendering end-user feedback, but the error() method on the indivual  
> rendered widget, in order to display the feedback message next to  
> the rendered widget.
>
> Wouldn't it make sense to set the validation errors on the errors  
> attribute, and set the invariant errors on a seperate  
> invariant_errors attribute on the form? Or maybe there's some other  
> way to get hold of the invariant errors and display them seperately?

A division of the two is something we had in a previous framework and  
not used (we displayed them all at the top indiscriminately, in  
addition to the per-widget errors), so Jim called WHUI (We Haven't  
Used It).  I wanted it, and with you on my side, I think Jim is OK  
with it. :-)

Gary