6.1.5 Math in Smalltalk

In this case, what happened was that the object 9 (an Integer), received a + message with an argument of 7 (also an Integer). The + message for integers then caused Smalltalk to create a new object 16 and return it as the resultant object. This 16 object was then given the printNl message, and printed 16 on the terminal.

Thus, math is not a special case in Smalltalk; it is done, exactly like everything else, by creating objects, and sending them messages. This may seem odd to the Smalltalk novice, but this regularity turns out to be quite a boon: once you’ve mastered just a few paradigms, all of the language “falls into place”. Before you go on to the next chapter, make sure you try math involving * (multiplication), - (subtraction), and / (division) also. These examples should get you started:

   8 * (4 / 2)
   8 - (4 + 1)
   5 + 4
   2/3 + 7
   2 + 3 * 4
   2 + (3 * 4)