/* srfi-1.c --- SRFI-1 procedures for Guile
*
- * Copyright (C) 1995, 1996, 1997, 2000, 2001, 2002, 2003, 2005, 2006,
- * 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+ * Copyright (C) 1995-1997, 2000-2003, 2005, 2006, 2008-2011, 2013
+ * 2014 Free Software Foundation, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
SCM_SIMPLE_VECTOR_SET (vec, i, SCM_CDR (lst)); /* rest of lst */
}
- count += scm_is_true (scm_apply (pred, args, SCM_EOL));
+ count += scm_is_true (scm_apply_0 (pred, args));
}
}
"circular.")
#define FUNC_NAME s_scm_srfi1_length_plus
{
- long len = scm_ilength (lst);
- return (len >= 0 ? SCM_I_MAKINUM (len) : SCM_BOOL_F);
+ size_t i = 0;
+ SCM tortoise = lst;
+ SCM hare = lst;
+
+ do
+ {
+ if (!scm_is_pair (hare))
+ {
+ if (SCM_NULL_OR_NIL_P (hare))
+ return scm_from_size_t (i);
+ else
+ scm_wrong_type_arg_msg (FUNC_NAME, 1, lst,
+ "proper or circular list");
+ }
+ hare = SCM_CDR (hare);
+ i++;
+ if (!scm_is_pair (hare))
+ {
+ if (SCM_NULL_OR_NIL_P (hare))
+ return scm_from_size_t (i);
+ else
+ scm_wrong_type_arg_msg (FUNC_NAME, 1, lst,
+ "proper or circular list");
+ }
+ hare = SCM_CDR (hare);
+ i++;
+ /* For every two steps the hare takes, the tortoise takes one. */
+ tortoise = SCM_CDR (tortoise);
+ }
+ while (!scm_is_eq (hare, tortoise));
+
+ /* If the tortoise ever catches the hare, then the list must contain
+ a cycle. */
+ return SCM_BOOL_F;
}
#undef FUNC_NAME
SCM_DEFINE (scm_srfi1_assoc, "assoc", 2, 1, 0,
(SCM key, SCM alist, SCM pred),
- "Behaves like @code{assq} but uses third argument @var{pred?}\n"
- "for key comparison. If @var{pred?} is not supplied,\n"
+ "Behaves like @code{assq} but uses third argument @var{pred}\n"
+ "for key comparison. If @var{pred} is not supplied,\n"
"@code{equal?} is used. (Extended from R5RS.)\n")
#define FUNC_NAME s_scm_srfi1_assoc
{
SCM_DEFINE (scm_srfi1_remove, "remove", 2, 0, 0,
(SCM pred, SCM list),
- "Return a list containing all elements from @var{lst} which do\n"
+ "Return a list containing all elements from @var{list} which do\n"
"not satisfy the predicate @var{pred}. The elements in the\n"
- "result list have the same order as in @var{lst}. The order in\n"
+ "result list have the same order as in @var{list}. The order in\n"
"which @var{pred} is applied to the list elements is not\n"
"specified.")
#define FUNC_NAME s_scm_srfi1_remove