Logic Programming
Overview
Logic programming is a programming paradigm based on formal logic. Programs in this paradigm consist of a set of logical rules and facts, from which answers to queries are inferred automatically. Unlike imperative programming, which uses statements to change a program's state, logic programming uses logical assertions.
History
"Logic programming emerged from the desire to use mathematical logic as both a declarative programming language and a programming language." - History of Programming Languages
Logic programming was first proposed in the late 1960s and early 1970s. Prolog, one of the most well-known logic programming languages, was developed in 1972 by Alain Colmerauer and his team at the University of Aix-Marseille. The paradigm has since influenced fields such as artificial intelligence, computational linguistics, and expert systems.
- 1972: First implementation of Prolog
- 1981: Introduction of the Predicate Compiler
- 1986: ISO Prolog standard established
Key Concepts
- Declarative Nature: Programs describe what is true rather than how to compute outcomes
- Backtracking: Automatic search through multiple solution paths
- Unification: Match terms with variables to satisfy logical relationships
- Relational Model: Relationships between facts rather than sequential operations
Example in Prolog
Query: ?- father(John, Mike).
Result: John = john
Applications
Artificial Intelligence
Used in expert systems for knowledge representation and automated reasoning
Natural Language Processing
Supports syntax parsing and semantics analysis in linguistics research
Databases
Enables deductive databases with rule-based query systems
Education
Used as a teaching tool for logic and computer science concepts
Comparison with Other Paradigms
| Paradigm | Focus | State Management |
|---|---|---|
| Logic Programming | Logical relationships | Implicit |
| Imperative Programming | Commands and statements | Explicit |
| Functional Programming | Mathematical functions | Immutable |