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(lset-difference!): Rewrite in C.

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This commit is contained in:
Kevin Ryde 2005-11-23 23:56:08 +00:00
commit 9dcee2b7a1
3 changed files with 62 additions and 3 deletions
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61
srfi/srfi-1.c
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@ -1208,6 +1208,67 @@ SCM_DEFINE (scm_srfi1_lset_adjoin, "lset-adjoin", 2, 0, 1,
#undef FUNC_NAME
SCM_DEFINE (scm_srfi1_lset_difference_x, "lset-difference!", 2, 0, 1,
(SCM equal, SCM lst, SCM rest),
"Return @var{lst} with any elements in the lists in @var{rest}\n"
"removed (ie.@: subtracted). For only one @var{lst} argument,\n"
"just that list is returned.\n"
"\n"
"The given @var{equal} procedure is used for comparing elements,\n"
"called as @code{(@var{equal} elem1 elemN)}. The first argument\n"
"is from @var{lst} and the second from one of the subsequent\n"
"lists. But exactly which calls are made and in what order is\n"
"unspecified.\n"
"\n"
"@example\n"
"(lset-difference! eqv? (list 'x 'y)) @result{} (x y)\n"
"(lset-difference! eqv? (list 1 2 3) '(3 1)) @result{} (2)\n"
"(lset-difference! eqv? (list 1 2 3) '(3) '(2)) @result{} (1)\n"
"@end example\n"
"\n"
"@code{lset-difference!} may modify @var{lst} to form its\n"
"result.")
#define FUNC_NAME s_scm_srfi1_lset_difference_x
{
scm_t_trampoline_2 equal_tramp = scm_trampoline_2 (equal);
SCM ret, *pos, elem, r, b;
int argnum;
SCM_ASSERT (equal_tramp, equal, SCM_ARG1, FUNC_NAME);
SCM_VALIDATE_REST_ARGUMENT (rest);
ret = SCM_EOL;
pos = &ret;
for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
{
elem = SCM_CAR (lst);
for (r = rest, argnum = SCM_ARG3;
scm_is_pair (r);
r = SCM_CDR (r), argnum++)
{
for (b = SCM_CAR (r); scm_is_pair (b); b = SCM_CDR (b))
if (scm_is_true (equal_tramp (equal, elem, SCM_CAR (b))))
goto next_elem; /* equal to elem, so drop that elem */
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (b), b, argnum, FUNC_NAME,"list");
}
/* elem not equal to anything in later lists, so keep it */
*pos = lst;
pos = SCM_CDRLOC (lst);
next_elem:
;
}
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG2, FUNC_NAME, "list");
*pos = SCM_EOL;
return ret;
}
#undef FUNC_NAME
/* Typechecking for multi-argument MAP and FOR-EACH.
Verify that each element of the vector ARGV, except for the first,

1
srfi/srfi-1.h
View file

@ -55,6 +55,7 @@ SCM_SRFI1_API SCM scm_srfi1_fold (SCM proc, SCM init, SCM list1, SCM rest);
SCM_SRFI1_API SCM scm_srfi1_last (SCM lst);
SCM_SRFI1_API SCM scm_srfi1_length_plus (SCM lst);
SCM_SRFI1_API SCM scm_srfi1_lset_adjoin (SCM equal, SCM lst, SCM rest);
SCM_SRFI1_API SCM scm_srfi1_lset_difference_x (SCM equal, SCM lst, SCM rest);
SCM_SRFI1_API SCM scm_srfi1_list_copy (SCM lst);
SCM_SRFI1_API SCM scm_srfi1_list_index (SCM pred, SCM list1, SCM rest);
SCM_SRFI1_API SCM scm_srfi1_list_tabulate (SCM n, SCM proc);

3
srfi/srfi-1.scm
View file

@ -588,9 +588,6 @@
(define (lset-intersection! = list1 . rest)
(apply lset-intersection = list1 rest)) ; XXX:optimize
(define (lset-difference! = list1 . rest)
(apply lset-difference = list1 rest)) ; XXX:optimize
(define (lset-xor! = . rest)
(apply lset-xor = rest)) ; XXX:optimize