9.2 Guide to Porting Code from Release 3

Release 4 does not provide a mode in which it is 100% compatible with earlier releases. However, this section provides guidelines for migrating Prolog code from release 3 to release 4.

1. First of all, make sure that your code runs in ISO execution mode. In release 3, the command line option --iso can be used.
2. A number of built-in predicates have been dropped. They are listed in the table below, along with their approximate substitutes. Refer to the documentation for each case.

   Dropped built-in	Replaced by
   get0/[1,2], get/[1,2]	get_code/[1,2], get_byte/[1,2]
   ttyget0/1, ttyget/1	get_code/2, get_byte/2
   put/[1,2], tab/[1,2]	put_code/[1,2], put_byte/[1,2]
   ttyput/1, ttytab/1	put_code/2, put_byte/2
   skip/[1,2]	skip_code/[1,2], skip_byte/[1,2]
   ttyskip/1	skip_code/2, skip_byte/2
   ttynl/0	nl/1
   ttyflush/0	flush_output/1
   fileerrors/0, nofileerrors/0	set_prolog_flag/2
   'C'/3	unification
   call_residue/2	call_residue_vars/2
   undo/1	prolog:undo/1
   help/0	the message system
   version/0	the message system
   version/1	the message system
   fcompile/1	save_files/2
   load/1	load_files/2
   load_foreign_files/2	splfr + load_foreign_resource/1
   require/1	use_module/2
   is_mutable/1	mutable/1
   module/1	set_module/1

3. The hook predicates user:term_expansion/[2,4] and user:term_expansion/3 are now called user:term_expansion/6 and Module:term_expansion/5 and have a modified API; see Term and Goal Expansion.
4. The set of library modules has been enriched by incorporating a subset of the Quintus Prolog library modules that we have deemed useful.

   The following library modules are not included in SICStus 4: clpb, flinkage, spaceout. library(objects) has been replaced by its Quintus counterpart, with a completely different API.

   The following table lists the affected SICStus 3 library modules.

   Affected module	Closest equivalent	Comment
   arrays	arrays3	a
   assoc	assoc3	b
   charsio	codesio	c
   clpfd	clpfd	d
   lists	lists3	e
   queues	queues3	f
   random	random3	g
   sockets	sockets	d
   system	system3	h

   Comments to the table:

   1. library(arrays3) is a code migration library module; the long-term solution is to use library(logarrs) instead.
   2. library(assoc3) is a code migration library module; the long-term solution is to use library(avl) instead.
   3. The syllable `chars' has been changed to `codes' throughout.
   4. Several API changes; see the documentation.
   5. library(lists3) is a code migration library module; the long-term solution is to use library(lists) instead.
   6. library(queues3) is a code migration library module; the long-term solution is to use library(queues) instead.
   7. library(random3) is a code migration library module; the long-term solution is to use library(random) instead.
   8. library(system3) is a code migration library module; the long-term solution is to use library(system), library(file_systems) and library(process) instead.