Alias of impliedBy reading in head-first order: head ifbody builds the Rule head :- body.
head
body
head :- body
if this value does not toTerm into a Struct.
Vararg overload of if: head.if(body1, body2, ...) builds the Rule head :- (body1, body2, ...).
head.if(body1, body2, ...)
head :- (body1, body2, ...)