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Revision history

This chapter summarizes the changes in release 3 wrt. previous SICStus Prolog releases as well as changes introduced by patch releases.

Changes in release 3

Backslashes (\) in strings, quoted atoms, and integers written in `0'' notation denote escape sequences. Character escaping can be switched off.
Multifile declarations are required in all files where clauses to a multifile predicate are defined. This complies with the ISO Prolog Standard.
The built-in predicate call_residue/2 has been modified so that goals that are disjunctively blocked on several variables are returned correctly in the second argument.
The built-in predicate setarg/3 has been removed. Its functionality is provided by the new built-ins create_mutable/2, get_mutable/2, update_mutable/2, and is_mutable/2, which implement a timestamp technique for value-trailing with low-level support.
The built-in predicates unix/1 and plsys/1 have been removed. Their functionality is provided by prolog_flag(argv,X), by the new halt/1 built-in, and by the new library(system) module which also contains several new predicates.
The socket I/O built-ins have been moved to the new library(sockets) module.
The built-in time_out/3 has been moved to the new library(timeout) module.
The built-ins term_hash/(2,4), subsumes_chk/2, and term_subsumer/3 have been moved to the new library(terms) module, which also contains operations for unification with occurs-check, testing acyclicity, and getting the variables of a term.
The foreign language interface (Prolog-to-C) has been extended with the types +chars, -chars and [-chars] for fast conversion between C strings and Prolog lists of character codes. Several new interface functions are available.
The memory handling of the C-to-Prolog interface has been simplified by passing each Prolog term as a "handle" object, called an SP_term_ref, making the functions SP_show_term() and SP_hide_term() obsolete.
The InterViews 2.6 based GUI module library(gmlib) has been replaced by the Tcl/Tk based library(tcltk). A version of library(gmlib) converted to SICStus Prolog release 3 is available from `ftp://ftp.sics.se/archive/sicstus3/gmlib.tar.gz'.
The library(objects) module has been enhanced.
- Inheritance is static, i.e. determined at object creation time, and is implemented as module importation.
- A new, very light-weight, type of object: instance.
- Attributes, efficient storage of terms in objects.
- Unprefixed goals in methods denote message passing to self. Prolog goals in methods must be prefixed by :.
In library(charsio), the open_chars_stream/(3-4) predicates have been replaced by open_chars_stream/2 and with_output_to_chars/(2-3).
The library(assoc) module now implements AVL trees instead of unbalanced binary trees.
The new library(atts) implements attributed variables, a general mechanism for associating logical variables with arbitrary attributes. Comes with a number of hooks that make it convenient to define and interface to constraint solvers.
The Boolean constraint solver has been moved to the new library(clpb) and is implemented on top of library(atts).
New constraint solvers for rationals (library(clpq)) and reals (library(clpr)), implemented on top of library(atts).
user:goal_expansion/3 is a new hook predicate for macro-expansion.
bb_put/2, bb_get/2, bb_delete/2, and bb_update/3 are new built-ins implementing blackboard primitives.
prolog_load_context/2 is a new built-in predicate for accessing aspects of the context of files being loaded.
user:file_search_path/2 is a new hook predicate providing an alias expansion mechanism for filenames.
gcd/2 is a new built-in function.
The statistics keyword walltime measures elapsed absolute time.
In Runtime Systems, ensure_loaded/1 and use_module/(1-3) have the same semantics as in Development Systems.
On some platforms, both a sequential and an experimental OR-parallel Development System can be built. The OR-parallel Development System is also known as Muse.
Native code compilation available for MIPS platforms.
Problems in native code compilation for certain SPARC models have been eliminated.
Performance improvements include emulated code speed, native code speed, and the foreign language interface.
The system has been ported to the DEC OSF/1 Alpha (a 64-bit platform).

Changes introduced in patchlevel 4

New built-in predicates and shell commands for creating and loading foreign language modules and creating customized development and runtime systems. Previous built-ins remain for backwards compatibility.
Slight changes in the C interface: hook variables are set by function calls, SP_foreign_reinit_hook is not supported.
The system has been ported to the Microsoft Win32 platform (Intel x86).
The system has been ported to the Macintosh.
The system has been ported to the OS/2 (32bit) platform (Intel x86).
If the init file `~/.sicstusrc' is not found, SICStus looks for `~/sicstus.ini'.
library(sockets): socket_select/5 arg 1 may be a, possibly empty, list of passive sockets, arg 3 returns a, possibly empty, list of new streams.
library(system): The following new predicates are provided: tmpnam/1, directory_files/2, file_property/2, delete_file/2, make_directory/1.
A new constraint solver for finite domains (library(clpfd)), implemented on top of library(atts).

Changes introduced in patchlevel 5

New built-in open/4, enables opening files in binary mode.
library(charsio): New predicate with_output_to_chars/4.
library(heaps): New predicates delete_from_heap/4, empty_heap/1, is_heap/1.
library(queues): New predicate is_queue/1.
library(sockets): New predicates: socket_accept/3, and socket_select/6 provide address of connecting client. hostname_address/2 resolves name/ip-number.
SP_atom_length returns the print name length of a Prolog atom.
Modification time instead of current time stored for loaded files.

Changes introduced in patchlevel 6

The finite domain constraint solver (library(clpfd)) has been enhanced by a programming interface for global constraints, improved compilation to library constraints and other performance enhancements, and by a number of new exported constraints.
library(objects): New hook predicate user:method_expansion/3.
library(sockets): socket_select/5 has extended functionality.

Changes introduced in version 7

The concept of patchlevels removed and replaced by versions.
library(chr): A new library module providing Constraint Handling Rules.
Jasper, a bi-directional Java-interface, consisting of extensions to the existing FLI and a new library module library(jasper).
Atom garbage collection, invoked by garbage_collect_atoms/0, and controlled by the agc_margin Prolog flag. New statistics options: atoms, atom_garbage_collection. New interface functions: SP_register_atom, SP_unregister_atom.
Calls with clean-up guaranteed, provided by call_cleanup/2, which replaces undo/1.
Source-linked debugging, controlled by the source_info Prolog flag.
Debugger enhancements: tracing of compiled code; a new debugger mode zip and built-ins zip/0, nozip/0; new debugger commands out n, skip i, quasi-skip i, zip, backtrace n, raise exception. Modules can be declared as hidden which disables tracing of their predicates.
Saved states are available in runtime systems, and are portable across platforms and between development and runtime systems. save/(1,2) are gone. In most cases, save_program/2 can be used in their place, with a little rearrangement of your code. Predicates can be declared as volatile.
A interface function SP_restore is the C equivalent of restore/1, which now only restores the program state, leaving the Prolog execution stacks unchanged.
The GNU Emacs interface was enhanced: source-linked debugging, new menus, speed, help functions, electric functions, indentation, portability, bug fixes.
The reader can return layout information about terms read in. New read_term/3 option: layout(-Layout). New hook predicate: user:term_expansion/4.
Module name expansion of goals is done prior to execution of meta-calls.
Imported predicates can be spied and abolished.
random:randset/3 returns a set in standard order.
db:db_canonical/(2,3) are new; can be used to check whether two TermRefs refer to the same term.
clpfd:serialized_precedence/3 and clpfd:serialized_precedence_resource/4 are new; model non-overlapping tasks with precedence constraints or sequence-dependent setup times.
In object method bodies, goals of the form :Goal are translated according to the manual. Earlier versions treated arguments occurring in the `:' position of meta-predicates specially.
A new interface function SP_raise_fault and interface macro SP_on_fault are available for handling runtime faults that cannot be caught as exceptions.
A new interface function SP_set_memalloc_hooks is available for redefining the memory manager's bottom layer. Related to that, there is a new command-line option `-m'.
Development and Runtime Systems have been reorganized internally. All use a runtime kernel shared object or DLL, and are initialized by restoring saved states. Development Systems additionally use a development kernel shared object or DLL.
The `-B' command-line option is gone in the start-up script, and some new options have appeared.
Under UNIX: new option `-base' to override the executable used by the start-script.
Under UNIX: improvements in the configure-script; better options to specify Tcl/Tk versions and paths.
Hookable standard-streams.
Floating-point operations on Digital Alpha are now IEEE-conformant.
reinitialise/0 does not load any initialization files given in `-i' or `-l' command line flags.
Under UNIX: New option -S to spmkrs and spmkds to link the SICStus Runtime Kernel (and development extensions for spmkds) statically into the executable.
?- [File1,File2,...] was broken.
require/1 did not find all directories.
Runtime systems could crash after GC.
Bugs in clp[qr]:dump/3, clp[qr]:expand/0, clp[qr]:noexpand/0.
The garbage collector reported too many bytes collected.
Memory overflows were not handled gracefully.
Imported predicates couldn't be abolished.
arrays:arefa/3, arrays:arefl/3, heaps:min_of_heap/5 are now steadfast.
Most library(clpfd) predicates now check the type of their arguments. Bugs fixed in relation/3, serialized/2, all_distinct/1.
frozen/2 could crash on an argument of the wrong type.
SP_get_list_n_chars does not require a proper list.
Problems with exceptions in embedded commands in source files.
Problems with load_files(Files, [compilation_mode(assert_all)]).
For load_files(Files, [if(changed)]), a non-module file is not considered to have been previously loaded if it was loaded into a different module.
Incorrect translation of if/3 goals in DCG rules.
On Win32, system:mktemp/2 sometimes returned filenames with backslashes in them.

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