# Ann: SWI-Prolog 8.3.27 **URL:** \ **Category:** Releases\ **Created:** [July 13, 2021, 2:14pm UTC](https://swi-prolog.discourse.group/t/ann-swi-prolog-8-3-27/4157 "2021-07-13T14:14:16Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![jan](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/jan/32/4_2.png) [@jan](https://swi-prolog.discourse.group/u/jan)\ **Post date:** [July 13, 2021, 2:14pm UTC](https://swi-prolog.discourse.group/t/ann-swi-prolog-8-3-27/4157/1 "2021-07-13T14:14:16Z")
Dear SWI-Prolog user, SWI-Prolog 8.3.27 is ready for download. Quite a bit has happened. Highlights: - A lot of work by @peter.ludemann on the Google protobufs library. See his announcement. - A new package and library(stomp), providing an out of the box solution to communicate with STOMP compatible message brokers such as RabbitMQ. - Several fixes to monotonic and incremental tabling. - More SICStus 4 emulation by @dgelessus. - clpqr enhancements: ISO exceptions and simpler as well as faster implementation of dump/3. - Several enhancements to the development tools: - Some enhancements to memory allocation as discussed here. # SWI-Prolog Changelog since version 8.3.26 - FIXED: If reevaluation changes conditions for a trie we must recompile the trie. - FIXED: tnot/1 table status evaluation during incremental re-evaluation. - ENHANCED: cli\_enable\_development\_system/0: avoid loading xpce when creating a state. - FIXED: Failure in incremental tabling if a leaf predicate is both tabled and dynamic. - FIXED: Issue#861: blobs with PL\_BLOB\_NOCOPY|PL\_BLOB\_UNIQUE must only compare the pointer. - BUILD: Issue#860: PGO building did not work with make on MacOS. - ADDED: Initial partial library(clpfd) to SICStus 4 emulation. - BUILD: Issue#859: Building main.pl docs now depends on xpce. - PORT: Allocator detection. - ADDED: trim\_heap/0 and a Prolog flag `malloc` to identify the malloc implementation and provide additional features when detected. - ADDED: Integrated stomp into the build process - ADDED: packages/stomp. - FIXED: lazy monotonic tabling requires a proper completion check. Such a table is complete if the dependencies do not contain any invalid incremental tables and all lazy queues are empty. Dependency tracking must be recursive and has to deal with loops. This fix avoids non-termination whil reevaluating lazy monotonic tables that contain cycles. - FIXED: While reevaluating a lazy monotonic node we should not consider it invalid. - FIXED: lazy monotonic update to set the current IDG node properly. - ENHANCED: explain/1 to support dicts, hide references from the cross-referencer and show file and line numbers for references from clauses. - ADDED: Supply a depth with the tracer `r` command to retry immediately on a parent goal. - ADDED: `[level] S` trace command to save a goal to the recorded database. - ENHANCED: Command line debugger ‘h’ command - ADDED: Command line debugger ‘g’ command to accept a negative number of frames as numeric parameter to print the outermost N frames rather than the innermost. As a result, the ‘-’ command (no spy) must be followed by the RETURN key. - FIXED: Issue#853: prolog\_walk\_code/1 did not respect the module\_class option, scanning all modules. - ENHANCED: `library(prolog_codewalk)`: avoid trying to find the file `-`. - FIXED: Avoid permission error when using autoload/1 after autoload/2. - ADDED: `library(main)`: cli\_parse\_debug\_options/2 and cli\_enable\_development\_system/0. - ADDED: mapsubterms/3 to recursively substitute arguments in a sub term. - FIXED: on\_signal/3 claims the signal is wrong on a type error on the handler. - FIXED: Avoid a race condition between thread\_join/2 and thread\_detach/1 and disallow multiple threads to join the same thread. Updated docs for thread\_join/2. - ENHANCED: trace/1,2 to work better on imported predicates, applying the wrapper directly to the implementation. - ADDED: File access mode `search` as an alias for `execute`. Improves compatibility with SICStus. - FIXED: Prevent source analysis to loop on an unbound module export list. - ADDED: library(file\_systems) to SICStus 4 emulation. ## Package clpqr - ENHANCED: Use high level copy built-ins to realize dump/3 and projecting\_assert/1. Share code between these. - MODIFIED: library(clpq) to throw ISO compliant exceptions ## Package plunit - ADDED: show\_coverage/2: Produce annotated files with coverage information. This information now also shows the number of entries and exits/failures. ## Package protobufs - TESTING: added many unit tests - ADDED: protobuf\_serialize\_to\_codes/3 fixed: uint64\_codes et al handling of signed/unsigned improved: error handling for uint64\_codes et al renamed integer\_zigzag to int64\_zigzag, int32\_codes =\> uint32\_codes, etc. moved some code into protobufs.c (uint64\_int32, etc.) simplified code by using freeze/2 and when/2 instead of nonvar/1 - ADDED: protobuf\_parse\_from\_codes/3 (using output of protoc-gen-swipl plugin) - ENHANCED: handle “group” add protobuf/unittest golden - BUILD: Run developer and “demo” tests as part of cmake/ctest build Use installed protoc Refactor Makefiles - TEST: Added unittest\*.proto and “golden” tests, edge case tests - ADDED: Plugin for protoc (protoc-gen-swipl) Copy logic from descriptor\_proto\_expand.pl to protoc-gen-swipl - FIXED: Some edge cases of negative or very large numbers Added round-trip tests Work-around issue #5 Added utf8 encoding directives Replace UTF8 strings by unicode codes, in case tests run in ASCII locale - ENHANCED: Added repeated\_embedded, unsigned32, unsigned64 - PORT: Avoid UTF-8 in comment to allow building using non-UTF-8 locales. - ENHANCED: handle repeated [packed=true] ## Package xpce - FIXED: Allow autoloading library(pce\_dispatch).