XSB Src (SVN)-old

Fix a coercion to avoid an MSVC warning.

Altered the manner in which the truth of negated subsumptive
predicates are evaluated. Originally I relied upon the interpretive
timestamp-based relevant-answer collection function, but this requires
the Time Stamp Indices to be present in the TST. If the producer has
completed before the collection, then these structures would have
already been be reclaimed.

The new approach checks for a relevant answer using the
trie_get_return/2 builtin. If one is found, then the literal can be
failed. Otherwise, the producer must be checked for completion and
whether the negative-delay flag has been set. This is performed
through a new builtin, lrd_success/2. Therefore, slg_not/1 is restored
for handling variant tabled predicates only.

optimize tail recursion in ptoc_longstring.

Added support for subsumption-based LRD stratified negation,
including:

o Modification of 't not'/1 to accept all predicates.

o Replacement of predicate get_producer_subgoal_frame/2 with a new
predicate get_producer_call/3 (ala get_call/3 and friends) to take
the subgoal and perform a tabling-strategy-dependent lookup,
returning a producer's subgoal frame and an answer template with
respect to that producer.

get_producer_call/3 aborts if given a non-tabled predicate and fails
if the tabled predicate hasn't been called before.

o Modification of slg_not/1 s.t. it takes two extra arguments: the
first is the answer template from get_producer_call/3, used by
negated, properly subsumed predicates for relevant-answer
collection; the second contains the subgoal which is negated, used
only for error reporting.

o Extension of certain C functions, e.g. get_variant_sf() and
get_subsumer_sf() to build and return, in an extra argument, the
answer template.

Fixed temporal order test so ensure_loaded will reload if file has
changed.

replaced 0/1 with true/false

call0 must be last when inlined by compiling with sysmod.... Dummy!

Modified get_producer_subgoal_frame/2 to carry an extra argument for
reporting the predicate's type. This will boost efficiency of 't not'/1
by allowing us to remove the call to table_state/4 which also performs a
lookup of the goal.

Added ptoc_longstring which is like ptoc_string, except that it
accepts a complex structure from Prolog and turns it into a C string.
It accepts lists, regular and ,-separated, containing atoms or small
integers, and constructs a string by concatenating the atoms or chars.
Small ints represent their ascii codes. It is recursive. This makes
it easier to send a long string across the C interface, without having
to construct a new atom for it.

Added ptoc_longstring which is like ptoc_string, except that it
accepts a complex structure from Prolog and turns it into a C string.
It accepts lists, regular and ,-separated, containing atoms or small
integers, and constructs a string by concatenating the atoms or chars.
Small ints represent their ascii codes. It is recursive. This makes
it easier to send a long string across the C interface, without having
to construct a new atom for it.