The Howdy Glossary

Ciao is an open-source programming language and development system that expands Prolog into logic, constraint, and Constraint Handling Rules (CHR) programming. It features robust type checking—both static and dynamic—to prevent errors in programs using dialects like Prolog, CLP(R), CLP(Q), and HiLog. Additionally, Ciao provides modules for defining reusable components with separate interfaces and implementations, coupled with an integrated development environment called CiaoPP for automatic documentation generation from annotated sources.

The language was developed by the Logic Programming Group at the Technical University of Madrid's School of Computer Science under Professor Manuel Hermenegildo’s leadership. Over time, multiple researchers contributed to its evolution. Ciao aims to support developers in building robust applications by offering tools for large codebase management and fostering modularity through a comprehensive module system.

Despite competition from other logic programming languages like Prolog, constraint languages such as MiniZinc, CHR systems, Haskell, and Scala—which provide strong type checking—Ciao distinguishes itself through its versatile support for multiple paradigms within a unified system. Its strong type checking enhances reliability while its various dialects offer flexibility across different domains. The efficient modular design facilitated by its module system aids in managing expansive codebases effectively. Furthermore, the CiaoPP environment automates documentation creation, augmenting developer productivity and project maintainability significantly.