Saturday, 28 November 2020

A Set back?

- or how could I forget some set operators.

Recently a colleague of mine asked me to review some old code, and a line similar to the one below pop into my view as strange:

if (doorStates * [dsClosed, dsUnlocked] <> []) then

It had been so many years since I had used that specific syntax, that I completely forgot about some of the set operators in Pascal and Delphi - so I thought I would write up a small post on Sets in Pascal/Delphi.

In regards to the silly doorStates example above - here is a little riddle: When is a door not a door?