Extensions to core Prolog. {#extensions}
=========================
YAP includes a number of extensions over the original Prolog
language. Next, we discuss how to use the most important ones.
+ @ref Rational_Trees
+ @ref AttributedVariables
+ @ref DepthLimited
+ @ref Tabling
+ @ref Threads
+ @ref Profiling
+ @ref YAPArrays
+ @ref Parallelism
In the description of the arguments of predicates the following
notation will be used:
+ a preceding plus sign will denote an argument as an "input
argument": the argument is read, not written, and it cannot be a free
variable at the time of the call.
+ a preceding minus sign will denote an "output argument";
+ an argument with no preceding symbol can be used in both ways.
