Hi Max,

Pharo doesn't have syntax for prefix operator like "-". 

The parser does accepts a "-" before literal numbers but it's not possible for arbitrary expressions.

However you have the message #negated .

negatedWidth
^ self width negated

Cheers,

Camille

On 16 juil. 2014, at 00:16, Verkoster Info <info@derVerkoster.de> wrote:

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