Syntactic Sugar

  In order to allow for more concise and readable definitions, the defEntity and defModelFragment forms provide some syntactic sugar.

:self
The symbol :self may be used to refer to the current instance of a model fragment. Note that it may not be used in the :conditions clause of a model-fragment definition with no superclasses, as this would place it outside of the scope within which the instance exists.

name
The user provided symbol for the name of a model fragment or entity may be used instead of :self, and is completely equivalent.

quantity
The symbol for any quantity may be used to refer to the appropriate quantity within the :consequences clause. This is completely equivalent to the more verbose form


(quantity :self)


which may also be used.

attribute
The symbol for any attribute may be used to refer to the appropriate attribute within the :consequences clause. This is completely equivalent to the more verbose form


(attribute :self)


which may also be used.

:substitutions
The :substitutions field defines a set of purely syntactic substitutions that are applied prior to the replacements described above. Each element in the field is a list containing a symbol and an arbitrary form. The form is substituted for the symbol wherever it appears within the original definition (excluding the substitutions field). The substitutions are not inherited, and are not available outside of the definition in any way.

participant
In a model fragment definition, the user provided symbol for each participant may be used to refer to that participant. Outside of the :conditions clause, the more verbose form


(participant :self)


may also be used (there are no participants in entity definitions).