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Merge pull request #1386 from triska/better_call_nth

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ENHANCED: more memory efficient call_nth/2 (#1264)
This commit is contained in:
Mark Thom
2022-04-03 01:38:37 -06:00
committed by GitHub
parent 86176dce8d 1fa8a0a969
commit 3be00045cf
1 changed files with 16 additions and 11 deletions
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27
src/lib/iso_ext.pl
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@@ -210,28 +210,33 @@ call_nth(Goal, N) :-
)
; true
),
setup_call_cleanup(call_nth_nesting(ID),
setup_call_cleanup(call_nth_nesting(C, ID),
( Goal,
retract(i_call_nth_nesting(ID,N0)),
bb_get(ID, N0),
N1 is N0 + 1,
asserta(i_call_nth_nesting(ID,N1)),
bb_put(ID, N1),
( integer(N) ->
N = N1,
!
; N = N1
)
),
( retract(i_call_nth_nesting(ID,_)),
retract(i_call_nth_counter(ID))
( bb_get(i_call_nth_counter, C) ->
C1 is C - 1,
bb_put(i_call_nth_counter, C1)
; true
)).
call_nth_nesting(ID) :-
( i_call_nth_counter(ID0) ->
ID is ID0 + 1
; ID = 0
call_nth_nesting(C, ID) :-
( bb_get(i_call_nth_counter, C0) ->
C is C0 + 1
; C = 0
),
asserta(i_call_nth_nesting(ID, 0)),
asserta(i_call_nth_counter(ID)).
number_chars(C, Cs),
atom_chars(Atom, Cs),
atom_concat(i_call_nth_nesting_, Atom, ID),
bb_put(ID, 0),
bb_put(i_call_nth_counter, C).
copy_term_nat(Source, Dest) :-