CONCURRENT PROLOG COMPILER ON TOP OF PROLOG.

A Concurrent Prolog compiler, whose target language is (sequential) Prolog, was implemented in Prolog. The object program obtained can further be compiled into machine codes by a Prolog compiler. Due to the similarity among the source, target and implementation languages, the compiler and the run-time support were small and very rapidly developed. Benchmark tests showed that (twice) compiled Concurrent Prolog programs ran 2. 7 to 4. 4 times faster and 2. 7 to 5. 3 times slower than comparable Prolog programs running on the interpreter and compiler, respectively, of the same Prolog system. After these experiments, the Concurrent Prolog compiler was modified to obtain a compiler of the new parallel logic programming language, GHC (guarded Horn clauses), and almost the same efficiency was achieved. These compilers will serve for parallel logic programming.