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+In ARF, variables are defined using the syntax `name:Type:qualifier`, where name
+is a name token and type is either just a name token describing what type it is,
+or a pointer to a value of that type or an array to a value of that type. The
+only supported qualifier is `:mut`, which marks the variable's data as mutable.
+Variables are immutable by default.
+
+Pointers are defined like `name:{Type}` and arrays are defined like
+`name:{Type length}` where length is an unsigned integer literal or an ellipsis
+token (..). If an integer token is given, the length of the array is static, and
+if an ellipsis is given, the length is dynamic and can be changed at runtime.
+
+Variables can be defined wherever they are used. For example, `set x:Int 5`
+defines a variable of type Int and sets it to 5.
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