declares Name to be an operator of the stated Type and Precedence.
Operators are a notational convenience
to read and write Prolog terms. You can define new operators using
The Precedence of an operator is used to disambiguate the way terms are parsed. The general rule is that the operator with the highest precedence is the principal functor.
The Type of an operator decides the position of an operator
and its associativity. In the atom that represents the type
f represents the position of the operator.
For example, a type
fx says that the operator is a prefix operator.
y indicates that the operator is associative
in that direction. For example, an operator of type
xfy is a right-associative, infix operator.
To cancel the operator properties of Name (if any) set Precedence to 0.
For more details, see ref-syn-ops