You can only put the minus sign ("-") before a literal number. Ej -12, - 4.4, -2/3, etc. But not in front of any other "non number" object (from the parser point of view): Ej: - #() size "only numbers may be negated" What you want to do can be performed sending the message #negated to the object returned by #width. So #negatedWidth would be: negatedWidth: ^self width negated Regards! Esteban A. Maringolo 2014-07-15 19:16 GMT-03:00 Verkoster Info <info@derverkoster.de>:
Hi,
I am using latest Pharo 3.0 + vm.
I have a method width with width
^ 115 * self ratio. in my understanding it returns a Number.
When I try to create a method negatedWidth
^ - (self width).
the UI tells me that only Numbers may be negated. I am not able to save the method. Am I on a wrong path or should that work and if how can I avoid the UI error message?
Regards
Max