Thomas Koenig <tomkoenig at mindspring.com> wrote:
> 
> I have a number of places in the code that look something like this:
> [id _ (FillInTheBlankMorph request: 'Enter the id of the post you''d
> like to jump to:' translated) asNumber ]
> 		 on: Error
> 		 do: [ self inform: 'That is not a valid number.'
> translated.
> 		        ^ nil ].
> Yet no mater what I key into the morph I don't trigger an error (don't
> see the error  message.)  
> Is there a good argument for keeping the error block?  If so can you
> suggest an test condition that would trigger it.
> 
> I'm inclined to remove this code, because it appears to add only
> complexity. 

I've played around with String>>asNumber. Here's what I find:

'1' asNumber -> 1
'a' asNumber -> 'Error: At least one digit expected here'
'1a' asNumber -> 1
'%' asNumber -> 'Error: At least one digit expected here'
'16rff' asNumber -> 'Error: At least one digit expected here'
'16rFF' asNumber -> 255

Personally, I'd prefer to see something like

  id := FillInTheBlankMorph requestNumber: 'foo' translated

where #requestNumber: would do one of the following:
* re-asked the user until they entered a valid number
* prevented the user entering anything other than a valid number (by highlighting the text as red if it's invalid, or not letting the user enter certain characters like )(&^%$"!# etc)

Now, I'm not sure what #requestNumber should return if the user presses cancel. Maybe #requestNumber: should do this

requestNumber: aString
    ^self requestNumber: aString default: nil

and #requestNumber:default: then returns some default value if the user presses cancel.

frank


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