http://www.google.co.uk/#q=%22enumeration+type%22 http://www.google.co.uk/#q=%22enumeration+type%22 http://en.wikipedia.org/wiki/Enumerated_type http://en.wiki

http://www.google.co.uk/#q=%22enumeration+type%22 http://www.google.co.uk/#q=%22enumeration+type%22 http://en.wikipedia.org/wiki/Enumerated_type http://en.wikipedia.org/wiki/Enumerated_type http://en.wikibooks.org/wiki/Ada_Programming/Types/Enumeration http://en.wikibooks.org/wiki/Ada_Programming/Types/Enumerati... In essence, an "enumerated type" is a collection of uninterpreted values. You can assign them to variables, you can compare them to each other, but they have no intrinsic structure. Unlike ints you can't add or multiply, unlike strings you can't concatenate or search for substrings. Hence the observation that symbols are not strings, but are elements of an infinite enumerated type. You can only refer to them, copy them, assign them, and compare them. They are atomic. No disrespect intended - different people have different backgrounds, and I know some very fine coders who don't know this sort of thing - but this is very, very elementary CS material, and easily found with a Google search. You may find it interesting to learn more about these sorts of basics. Although it often doesn't help directly, it can provide useful insights to have different points of view and points of reference.