SWI-Prolog offers a comprehensive free Prolog environment. It has been in development since 1987 and extended for requirements of real world applications, but is also widely used in research and education. It includes a nice command line interface, fast and transparent compilation, a debugger, profiling features. It also has the ability to integrate with C code, and already comes with packages for threading and process management, encryption, TCP/IP, TIPC, ODBC, SGML/XML/HTML, RDF, HTTP, graphics manipulation and output. It's also cross-platform.
minor feature: PPA: Removed eoan from PPA list.Updated bench..: : expand_file_name/2 for Windows: double UTF-8 encoding..MODIFIED: portray_clause/1,2,3: portray `(a,b),c` the same as `a,(b,c)`..Updated sgml..MODIFIED: frozen/2 now reports any goal that is delayed on some variable..MODIFIED: numbervars/4 using the `singletons(true)` option to number ..ENHANCED: Allow listing and source level deger to work for clauses..ENHANCED: Compile simple arg/3 calls to the VM..Updated pldoc..Ensure uniqueness of goals in frozen/2..DOC: : read_history/6 wrong info for substituting the event..: : Deflags such as `print_write_options` in a saved..: Handle failure inside 'fast' opcodes which D_BREAK replaces with..: frozen/2 could fail after recent enhancements..: Possible crash in tabling, notably occurring on MacOS due to w ..ENHANCED: frozen/2 to avoid copying. This not only enhances performance..Added test for frozen/2..MODIFIED: qsave_program/2: preserve the `autoload` flag in the calling..Updated sgml..MODIFIED: : Added read_term_with_history/2 and moved read_hi ..Preparing version 8.3.7..toplevel query with variables.