3 Parenthetical Datalog Module Language

▼ |  | Datalog: Deductive database programming

1 | Datalog Module Language
2 | Tutorial
3 | Parenthetical Datalog Module Language
4 | Racket Interoperability
5 | Acknowledgments

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### 3`` Parenthetical Datalog Module Language

#lang datalog/sexp

The semantics of this language is the same as the normal Datalog language, except it uses the parenthetical syntax described in Racket Interoperability.

All identifiers in racket/base are available for use as predicate symbols or constant values. Top-level identifiers and datums are not otherwise allowed in the program. The program may contain require expressions.

The following is a program:

#lang datalog/sexp
(! (edge a b))
(! (edge b c))
(! (edge c d))
(! (edge d a))
(! (:- (path X Y)
(edge X Y)))
(! (:- (path X Y)
(edge X Z)
(path Z Y)))
(? (path X Y))

This is also a program:

#lang datalog/sexp
( require racket/math)
(? ( sqr 4 :- X))

The Parenthetical Datalog REPL accepts new statements that are executed as if they were in the original program text, except require is not allowed.

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