ELPI

ELPI: Fast, Embeddable, λProlog Interpreter. We present a new interpreter for λProlog that runs consistently faster than the byte code compiled by Teyjus, that is considered the best available implementation of λProlog. The key insight is the identification of a fragment of the language, which we call reduction-free fragment (βλ), that occurs quite naturally in λProlog programs and that admits constant time reduction and unification rules.