Prolog

Logic programming · 1972Actively developed

Logic programming through relations, unification and search.

Logic

Tracked release

Version: SWI-Prolog 10.0
Artifact: Runtime feature series
Published: Date not verified
Source checked: 2026-10-22

https://www.swi-prolog.org/download/stable

Use & ecosystem

Suited for: Web backends, Symbolic / logic programming
Family / tradition: Logic programming
Maturity: Stable niche
Ecosystem breadth: Focused

Long-lived implementations support Stable niche. Logic and constraint tooling can be deep, but this is not a broadly adopted general application ecosystem.

Industry & practical use

Knowledge representation, symbolic reasoning and constraint-based applications are natural fits. Some implementations also provide useful web-service and integration libraries.

Compilers, libraries & tooling

SWI-Prolog is the representative implementation here, not the owner of Prolog. Module systems, libraries, compilation and extensions differ across implementations.

Platforms & deployment

General toolchains: Linux, Windows, macOS
Specialized tooling: Browser
Browser execution: WebAssembly
Native cross-compilation: Not the usual deployment model

SWI-Prolog supplies desktop/server builds and a specialized Wasm browser route. Other implementations have different target lists.

Programs normally deploy with a compatible Prolog system. Bytecode portability and runtime cross-builds are separate issues.

Project health & support

SWI-Prolog has maintained tooling and a community; other Prolog systems have independent support arrangements. Language-standard stability does not imply interchangeable libraries.

Use, ecosystem & platform assessment reviewed 2026-10-22 · Sources below

History & origin

Prolog originated in the early 1970s in work by Alain Colmerauer and Philippe Roussel, with Robert Kowalski’s logic-programming ideas providing an important foundation. Several implementations and dialects developed.

Creators: Alain Colmerauer, Philippe Roussel, Robert Kowalski
Origin: 1972 — Conventional origin year for the first implementation.

Influences & descendants

Influenced by

Not yet documented in this catalogue.

Influenced in this catalogue

No linked entries yet.

Language features

Typing: Dynamic
Execution: Bytecode VM
Block structure: Explicit delimiters
Semicolons: Not statement separators
Lexical closures: Partial
Namespaced modules: Partial
Pattern matching: Yes
Macro system: Term expansion; implementation-dependent

Implementation notes

Semicolon is disjunction, not a statement terminator. Clauses end in periods.
Unification supplies structural matching. Modules, closure conveniences and term expansion are implementation-dependent.

Sources & references

Project overview: https://www.swi-prolog.org/
Language / implementation reference: https://www.swi-prolog.org/pldoc/doc_for?object=manual

Use, ecosystem & platform sources

Project overview: https://www.swi-prolog.org/
Language / implementation reference: https://www.swi-prolog.org/pldoc/doc_for?object=manual

See the classification definitions for implementation-dependent features. Influence links cover the entries documented here.

Links