ATLRUG - Cucumber

May 15th, 2009 Tim Kadom

Click to Play

Posted in Random | 1 Comment »

ruby setter syntactic magic.

May 1st, 2009 tkadom

suppose you had the following code, What output would you expect to see?

   #!/usr/bin/ruby

   class RetTest

     attr_reader :val

     def val=(newval)
      @val = newval <  100 ? newval : 100
     end

     def setval(newval)
      @val = newval <  100 ? newval : 100
     end
   end

   f = RetTest.new
   g = RetTest.new

   puts f.val= 120
   puts f.val

   puts g.setval 120
   puts g.val

I thought it was gonna be turtles all the way down.

100 100 100 100

suprise to me the output was actually:

120 100 100 100.  

Well to be clear, this was not the code that i originally started with, but its the code that illustrates a point.  The setter in ruby actually does not do exactly what i would expect.  I was thinking the last value assigned would be returned regardless.  Something magical happens with the syntactic niceness that we have with our setters though.  Instead of returning the value of the assignment, the rvalue is returned.  I am not sure why this happens, and was wondering if anyone had any thoughts on the matter…

Posted in Random | 3 Comments »