Definitions

A definition is an entry of type #def The name of a definition entry is the name of the type it defines and its value is a function that can be evaluated to determine if a term is an instance of the type. Functions may refer to their argument by using the special terms #self or #arg.

The following definition returns true for all integers between 0 and 10 (for readability we assume namespaces basic-ops, logic-ops, and numerical-ops from eval-nms.aiddl.

(#def SmallInteger 
  (and
    (has-type #self ^integer)
    (>= #self 0)
    (<= #self 10)))

Within the same module, this function can be evaluated by refering to its name at the beginning of a tuple. For instance

($SmallInteger 5)

would evaluate to true.

Note that in most cases, functions are better defined in a programming language with an AIDDL core. However, it can be convenient to use #def do define constraints for types or assemble parts of a model from parameters.

Last modified: 17 March 2025