Architecture The Alma Abstract Architecture (AAA) is the virtual architecture used during the intermediate code generation phase of the Alma-0 compiler. The AAA combines the features of the abstract machines for imperative languages and for logic programming languages. The compiler compiles the Alma-0 programs into AAA programs. In a second phase the AAA instructions are translated into C statements. As the Alma-0 language itself, the AAA aims to combine the best of both worlds; elements were taken from virtual machines used to compile imperative languages (in particular the RISC architecture described in Wirth [1996, pp. 55--59], and from the WAM machine used to compile a logical language (see Ait-Kaci [1991]). Still, the AAA resembles most the virtual machines used in the compilation of imperative languages. The additions made to provide for the extensions of the Alma-0 language are ---the failure handling instructions ONFAIL, FAIL, 40 \Delta Krzysztof R. Apt et al ---the log ...

We provide here a computational interpretation of first-order logic based on a constructive interpretation of satisfiability w.r.t. a fixed but arbitrary interpretation. In this approach the formulas themselves are programs. This contrasts