Max, Am 16.07.2014 um 00:16 schrieb Verkoster Info <i...@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? > It is all objects and you need to send a message to them in order to have a result. So a prefixed - (minus sign) won't work. But this is a very good demonstration what I have often encountered while learning smalltalk. The most obvious choice is the right one. The solution is already in the method name. You can write it negatedWidth ^ self width negated :) You see. It is easy and it makes completely sense now, no? Norbert
