By Joe Rumsey
About the author: CTP Programmer, a.k.a Mr Ogre on the forums
Built-in variables in SLIC serve two purposes. First, they contain information about objects in the game. For example, when you have code that deals with a city, it will have access to a variable named city. To find out how many people live in the city, you can use city.population. Because you may sometimes have to deal with more than one city, an index as to which city you mean can be inserted between the container name and the member you are interested in. For example, city.1.population is the same as city.population since 1 is the default index if none is given. But city.2.population is the population of the second city in the current context. This use of indices is not specific to the city container, it works for all containers except g, clicked, and special.