SMT-LIB Compliance

Mostly compliant with --lang smt, but you get extra strict/conformance things with the --smtlib command line option.

There are areas where we don't support full functionality, or where we are not compliant:

• We do not yet support the to_real or to_int functions, nor the is_int predicate, from the Reals_Ints theory.
• We do not yet support unsat core extraction (the get-unsat-core command)

Also:

• We do not yet support Boolean terms, e.g., function symbols that take Boolean arguments or arrays of Boolean. This limitation should be fixed by the 1.0 release.
• We do not yet support abstract values. An array can itself be printed as a term, and even a function can be printed (as a lambda). We plan to support abstract values when running in --smtlib compliance mode, by the 1.0 release.