Prolog - Programming language

Prolog is a programming language created in 1972 by Alain Colmerauer.

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Prolog is a general-purpose logic programming language associated with artificial intelligence and computational linguistics. Prolog has its roots in first-order logic, a formal logic, and unlike many other programming languages, Prolog is intended as primarily a declarative programming language: the program logic is expressed in terms of relations, represented as facts and rules. A computation is initiated by running a query over these relations. Read more on Wikipedia...

Tags: programming language
There are at least 22,512 Prolog repos on GitHub
Early development of Prolog happened in University of Edinburgh and Aix-Marseille University
The Google BigQuery Public Dataset GitHub snapshot shows 9k users using Prolog in 11k repos on GitHub
Check out the 8 Prolog meetup groups on Meetup.com.
There are 7,884 members in the Prolog subreddit
There are 156 Project Euler users using Prolog
Explore Prolog snippets on Rosetta Code
Prolog on HOPL
Prolog ranks #41 in the TIOBE Index
Prolog Ubuntu package
ANTLR grammar for Prolog
Pygments supports syntax highlighting for Prolog
GitHub supports syntax highlighting for Prolog
Prolog appears in the Quine Relay project
Learn Prolog on exercism.
There is 1 Jupyter Kernel for Prolog
There is a central package repository for Prolog
Indeed.com has 79 matches for "prolog developer".
See also: (17 related languages) POPLOG, SWI Prolog, Visual Prolog, Mercury, Oz, Erlang, Datalog, Unicode, ΛProlog, HTML, XML, RDF, OWL, ActionScript, Lisp, PLANNER, AgentSpeak
16 PLDB concepts link to Prolog: cloc, CLPR, Euphoria, Fern, GAEA, juicy, mal, OpenCV, Perl, Picat, Podlite, Progol, proto-GNOSIS, Pygments, Scryer Prolog, SWI Prolog

Example from Riju:

:- initialization main.

main :-
    write("Hello, world!"), nl.

Example from hello-world:

helloWorld :-
  write('Hello World').

:- helloWorld.

Example from the Hello World Collection:

% Hello World in Prolog

hello :- display('Hello World!') , nl .

Example from Linguist:

%6.8
subset(Set, Subset) :-
	append(L1, Subset, Set).
powerset(Set, Subset) :-
	bagof(Subset, subset(Set, Subset), Subset).

Example from Wikipedia:

rule(q0, 1, q0, 1, right).
rule(q0, b, qf, 1, stay).

Language features

Feature	Supported	Example	Token
Standard Library	✓	write('Hello, World!'), nl.
Binary Literals	✓	% 0b[01]+
Integers	✓	% \d\d?\'[a-zA-Z0-9]+
Floats	✓	% (\d+\.\d\|\d\.\d+)([eE][+-]?[0-9]+)?
Hexadecimals	✓	% 0x[0-9a-fA-F]+
Octals	✓	% 0o[0-7]+
Case Sensitivity	✓
Strings	✓	'Hello world'	'
MultiLine Comments	✓	/* A comment */	/* */
Print() Debugging	✓		write
Line Comments	✓	% A comment	%
Macros	✓	term_expansion(parent_child(Parent, Child), child_parent(Child, Parent)). parent_child(trevor, simon). % With the above definitions, we can query (even though the predicate child_parent/2 is nowhere explicitly defined in the code above): ?- child_parent(Child, Parent). Child = simon, Parent = trevor.
Type Inference	✓
Comments	✓
Case Insensitive Identifiers	X
Semantic Indentation	X