With the instruction \c;distance( , )\n; you can calculate the distance between two positions.
\b;Basic use
If you write \c;position\n; alone, this gives you the position of the bot that executes the program. If you write the name of a variable followed by \c;.position\n;, this gives you the position of the object described in the variable.
Here is a program that moves forward, covering exactly the distance between the bot and the closest ant: