It's interesting to see the history of any given piece of syntax. This specific one is called augmented assignment or compound assignment: https://en.wikipedia.

It's interesting to see the history of any given piece of syntax. This specific one is called augmented assignment or compound assignment: https://en.wikipedia.org/wiki/Augmented_assignment https://en.wikipedia.org/wiki/Augmented_assignment +:= in Algol68 =+ in B += in C