SWI-Prolog -- engine_next

Documentation
- Reference manual
  - Coroutining using Prolog engines
    - Engine predicate reference
- Packages

Availability:built-in

[det]engine_next_reified(+Engine, -Term)

Similar to engine_next/2, but instead of success, failure or raising an exception, Term is unified with one of terms below. This predicate is provided primarily for compatibility with Lean Prolog.

the(Answer): Goal succeeded with Template bound to Answer or Goal yielded with a term Answer.
no: Goal failed.
throw(Exception): Goal raised Exception.

History

Modified in 9.1.8 (👉0ded2bf) engine_next_reified/2 to return an exception as throw(Exception) rather than exception(Exception). Compatibile with e.g. call_time/3.