Prolog Language Operators Predefined operators


Example

Predefined operators according to ISO/IEC 13211-1 and 13211-2:

PriorityTypeOperator(s)Use
1200xfx:- -->
1200fx:- ?-Directive, query
1100xfy;
1050xfy->
1000xfy','
900fy\+
700xfx= \\=Term unification
700xfx== \\== @< @=< @> @>=Term comparison
700xfx=..
700xfxis =:= =\= < > =< >=Arithmetic evaluation and comparison
600xfy:Module qualification
500yfx+ - /\ \/
400yfx* / div mod // rem << >>
200xfx**Float power
200xfy^Variable quantification, integer power
200fy+ - \Arithmetic identity, negation ; bitwise complement

Many systems provide further operators as an implementation specific extension:

PriorityTypeOperator(s)Use
1150fxdynamic multifile discontiguous initializationStandard directives
1150fxmode public volatile block meta_predicate
900fyspy nospy