Ciao Prolog is a modern version of Prolog created in Spain (Mera et al. 2007, Hermenegildo et al XXXXXXXXXXCiao offers a complete Prolog system, but its novel modular design allows both restricting...

Ciao Prolog is a modern version of Prolog created in Spain (Mera et al. 2007, Hermenegildo et al. 2007). Ciao offers a complete Prolog system, but its novel modular design allows both restricting and extending the language. As a result, it allows working with fully declarative subsets of Prolog and also to extend these subsets both syntactically and semantically. Most importantly, these restrictions and extensions can be activated separately on each program module so that several extensions can coexist in the same application for different modules. Ciao also supports (through such extensions) programming with functions, higher-order (with predicate abstractions), constraints, and objects, as well as feature terms (records), persistence, several control rules (breadth-first search, iterative deepening), concurrency (threads/engines), a good base for distributed execution (agents), and parallel execution. Libraries also support WWW programming, sockets, external interfaces (C, Java, TclTk, relational databases, etc.).