[Seaside] How to do validation such as for money (with a currency class) in WAEditDialog subclasses?

[Yar Hwee Boon]

I have a WAEditDialog subclass with a field called amount, which I am  
using a currency class (which understands #amount: and #amount) to  
represent. What I do is to implement a field renderer like:

renderAmountOn: html
	html
		textInputWithValue: model amount
		callback: [:v | model amount amount: v].

However, how do I validate input which is non-digit? The #amount:  
implementation assumes a number, and will throw some error. Similar for  
WAHtmlRenderer>>dateInputWithValue:callback:. BTW, does no one use  
#dateInputOn:of:? Seems odd that its missing... Thanks.

-- 
Regards
HweeBoon
MotionObj