Basic types

Rubbish features a typical set of built-in values: integers which transparently become bignums, floating-point numbers, functions, tuples, and the soon-to-be-explained variants. Every missing value is represented by these. (Technically, numbers and tuples could be subsumed by variants---and are, in the semantics---but practically, they are treated as separate due to their wide use.)

Variants are an untyped version of the tagged sums featured in statically typed functional languages. A variant always begins with either a capital letter or a backtick.

Nullary variants are treated not unlike symbols in Lisps or Ruby. The only meaningful operations on them are comparison or pattern-matching. Certain nullary variants are used as distinguished values; for example, False is the false value and Void is the return type of most side-effectful functions. In addition, nullary variants subsume most uses of enumerations and function as keywords, e.g. file := open("filename.txt", R).

However, variants can also take an arbitrary number of arguments. For example, evaluating Point(1, 2+3) results in the value Point(1, 5); the intuition behind them can be captured in a number of ways: you can think of an n-ary variant as an (n+1)-ary variant with a symbol as its first element, or as