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fix take-right and drop-right for improper lists

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* libguile/srfi-1.h:
* libguile/srfi-1.c (scm_srfi1_drop_right, scm_srfi1_take_right): Remove
  these internal functions, replacing with Scheme implementations.

* module/srfi/srfi-1.scm (take-right, drop-right): Add these impls from
  the reference code.  They do the right thing for improper lists,
  according to the spec, but they diverge for circular lists.  Oh well.

* test-suite/tests/srfi-1.test ("drop-right", "take-right"): Add more
  tests.
This commit is contained in:
Andy Wingo 2011-08-12 23:26:15 +02:00
parent 335c8a89a2
commit e7a81c7acd
4 changed files with 29 additions and 44 deletions
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39
libguile/srfi-1.c
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@ -568,28 +568,6 @@ SCM_DEFINE (scm_srfi1_delete_duplicates_x, "delete-duplicates!", 1, 1, 0,
#undef FUNC_NAME
SCM_DEFINE (scm_srfi1_drop_right, "drop-right", 2, 0, 0,
(SCM lst, SCM n),
"Return a new list containing all except the last @var{n}\n"
"elements of @var{lst}.")
#define FUNC_NAME s_scm_srfi1_drop_right
{
SCM tail = scm_list_tail (lst, n);
SCM ret = SCM_EOL;
SCM *rend = &ret;
while (scm_is_pair (tail))
{
*rend = scm_cons (SCM_CAR (lst), SCM_EOL);
rend = SCM_CDRLOC (*rend);
lst = SCM_CDR (lst);
tail = SCM_CDR (tail);
}
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P(tail), tail, SCM_ARG1, FUNC_NAME, "list");
return ret;
}
#undef FUNC_NAME
SCM_DEFINE (scm_srfi1_find, "find", 2, 0, 0,
(SCM pred, SCM lst),
"Return the first element of @var{lst} which satisfies the\n"
@ -924,23 +902,6 @@ SCM_DEFINE (scm_srfi1_remove_x, "remove!", 2, 0, 0,
}
#undef FUNC_NAME
SCM_DEFINE (scm_srfi1_take_right, "take-right", 2, 0, 0,
(SCM lst, SCM n),
"Return a list containing the @var{n} last elements of\n"
"@var{lst}.")
#define FUNC_NAME s_scm_srfi1_take_right
{
SCM tail = scm_list_tail (lst, n);
while (scm_is_pair (tail))
{
lst = SCM_CDR (lst);
tail = SCM_CDR (tail);
}
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P(tail), tail, SCM_ARG1, FUNC_NAME, "list");
return lst;
}
#undef FUNC_NAME
void
scm_register_srfi_1 (void)