... system^1.1

Many of the Prolog components of XSB are based on PSB-Prolog [48], which itself is based on version 2.0 of SB-Prolog [13].

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... results).^2.1

This convention does not apply to the subdirectories of the examples directory, which illustrate advanced features of XSB.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... symbols ^3.1

Operator symbols can be exported as any other symbols, but their precedence must be redeclared in the importing module.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... XSB^3.2

Any parallelisation directives ( parallel) are simply ignored by the compiler, but do not result in syntax errors to enhance compatibility with various other earlier versions of PSB-Prolog.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... systems^3.3

The most common uses of mode declarations in Prolog systems are to reduce the size of compiled code, or to speed up a predicate's execution.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... factoring:^3.4

Unification factoring was once called transformational indexing, hence the abbreviation ti in the compiler directives

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

...sec:table-aggregation ^5.1

We also note that the library subsumes contains routines for checking variance and subsumption.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... aborted^5.2

A more sophisticated solution is proposed in [41].

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... module^6.1

The only limitation is that blah must indeed be a module in the sense that it exports at least one symbol.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... 0$\}$.^8.1

A term like

$\{$foo$\}$ is just a syntactic-sugar for the term

'$\{\}$'(foo).

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... brackets.^8.2

Readers familiar with Quintus Prolog may notice the difference in the treatment of the various kinds of not. For example, in Quintus Prolog a not/1 that is not enclosed within curly brackets is interpreted as a non-terminal grammar symbol.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.