Can I program Tasker-like programs to do stuff if specific WiFi network is in range?
In Tasker create a new State based context and choose Net as
state category.
 

Then choose Wifi Near as net action:
 


This will bring a screen where you can input data about the WiFi access point you are interested in. If you are near the desired WiFi access point then you could just press the scan button (the button with lens symbol at left end of the text SSID).

This scans the near by access points and lists its details. Simply select the one which you are interested in.  Now you are good to go to add an entry task and exit task to whatever you want.