Can someone explain to me this. This is in off topic so i think its not obeying the rules.

And please dont spam this, im seriously asking to native English speakers.

I dont really understand this form of words.

http://s5.postimg.org/oy4zsfsqv/Screenshot_2015_12_09_17_50_47.jpg


This was taken from a programming book page. And the word this is a keyword.

Now i would like to ask because im confused why it was written as have? My brain cant understand this.