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(drop-right!, drop-while,

lset-adjoin, reduce, reduce-right, span, take!, take-while,
take-while!): Rewrite in C.
This commit is contained in:
Kevin Ryde 2005-05-03 22:56:01 +00:00
parent da02b978d0
commit 597dbd4eea
2 changed files with 391 additions and 0 deletions

View file

@ -557,6 +557,53 @@ SCM_DEFINE (scm_srfi1_drop_right, "drop-right", 2, 0, 0,
#undef FUNC_NAME #undef FUNC_NAME
SCM_DEFINE (scm_srfi1_drop_right_x, "drop-right!", 2, 0, 0,
(SCM lst, SCM n),
"Return the a list containing the @var{n} last elements of\n"
"@var{lst}. @var{lst} may be modified to build the return.")
#define FUNC_NAME s_scm_srfi1_drop_right_x
{
SCM tail, *p;
if (scm_is_eq (n, SCM_INUM0))
return lst;
tail = scm_list_tail (lst, n);
p = &lst;
/* p and tail work along the list, p being the cdrloc of the cell n steps
behind tail */
for ( ; scm_is_pair (tail); tail = SCM_CDR (tail))
p = SCM_CDRLOC (*p);
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P(tail), tail, SCM_ARG1, FUNC_NAME, "list");
*p = SCM_EOL;
return lst;
}
#undef FUNC_NAME
SCM_DEFINE (scm_srfi1_drop_while, "drop-while", 2, 0, 0,
(SCM pred, SCM lst),
"Drop the longest initial prefix of @var{lst} whose elements all\n"
"satisfy the predicate @var{pred}.")
#define FUNC_NAME s_scm_srfi1_drop_while
{
scm_t_trampoline_1 pred_tramp = scm_trampoline_1 (pred);
SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
if (scm_is_false (pred_tramp (pred, SCM_CAR (lst))))
goto done;
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG2, FUNC_NAME, "list");
done:
return lst;
}
#undef FUNC_NAME
SCM_DEFINE (scm_srfi1_filter_map, "filter-map", 2, 0, 1, SCM_DEFINE (scm_srfi1_filter_map, "filter-map", 2, 0, 1,
(SCM proc, SCM list1, SCM rest), (SCM proc, SCM list1, SCM rest),
"Apply @var{proc} to to the elements of @var{list1} @dots{} and\n" "Apply @var{proc} to to the elements of @var{list1} @dots{} and\n"
@ -756,6 +803,58 @@ SCM_DEFINE (scm_srfi1_list_copy, "list-copy", 1, 0, 0,
#undef FUNC_NAME #undef FUNC_NAME
SCM_DEFINE (scm_srfi1_lset_adjoin, "lset-adjoin", 2, 0, 1,
(SCM equal, SCM lst, SCM rest),
"Add to @var{list} any of the given @var{elem}s not already in\n"
"the list. @var{elem}s are @code{cons}ed onto the start of\n"
"@var{list} (so the return shares a common tail with\n"
"@var{list}), but the order they're added is unspecified.\n"
"\n"
"The given @var{=} procedure is used for comparing elements,\n"
"called as @code{(@var{=} listelem elem)}, ie.@: the second\n"
"argument is one of the given @var{elem} parameters.\n"
"\n"
"@example\n"
"(lset-adjoin eqv? '(1 2 3) 4 1 5) @result{} (5 4 1 2 3)\n"
"@end example")
#define FUNC_NAME s_scm_srfi1_lset_adjoin
{
scm_t_trampoline_2 equal_tramp;
SCM l, elem;
equal_tramp = scm_trampoline_2 (equal);
SCM_ASSERT (equal_tramp, equal, SCM_ARG1, FUNC_NAME);
SCM_VALIDATE_REST_ARGUMENT (rest);
/* It's not clear if duplicates among the `rest' elements are meant to be
cast out. The spec says `=' is called as (= list-elem rest-elem),
suggesting perhaps not, but the reference implementation shows the
"list" at each stage as including those "rest" elements already added.
The latter corresponds to what's described for lset-union, so that's
what's done here. */
for ( ; scm_is_pair (rest); rest = SCM_CDR (rest))
{
elem = SCM_CAR (rest);
for (l = lst; scm_is_pair (l); l = SCM_CDR (l))
if (scm_is_true (equal_tramp (equal, SCM_CAR (l), elem)))
goto next_elem; /* elem already in lst, don't add */
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P(l), lst, SCM_ARG2, FUNC_NAME, "list");
/* elem is not equal to anything already in lst, add it */
lst = scm_cons (elem, lst);
next_elem:
;
}
return lst;
}
#undef FUNC_NAME
/* Typechecking for multi-argument MAP and FOR-EACH. /* Typechecking for multi-argument MAP and FOR-EACH.
Verify that each element of the vector ARGV, except for the first, Verify that each element of the vector ARGV, except for the first,
@ -1116,6 +1215,132 @@ SCM_DEFINE (scm_srfi1_partition_x, "partition!", 2, 0, 0,
#undef FUNC_NAME #undef FUNC_NAME
SCM_DEFINE (scm_srfi1_reduce, "reduce", 3, 0, 0,
(SCM proc, SCM def, SCM lst),
"@code{reduce} is a variant of @code{fold}, where the first call\n"
"to @var{proc} is on two elements from @var{lst}, rather than\n"
"one element and a given initial value.\n"
"\n"
"If @var{lst} is empty, @code{reduce} returns @var{def} (this is\n"
"the only use for @var{def}). If @var{lst} has just one element\n"
"then that's the return value. Otherwise @var{proc} is called\n"
"on the elements of @var{lst}.\n"
"\n"
"Each @var{proc} call is @code{(@var{proc} @var{elem}\n"
"@var{previous})}, where @var{elem} is from @var{lst} (the\n"
"second and subsequent elements of @var{lst}), and\n"
"@var{previous} is the return from the previous call to\n"
"@var{proc}. The first element of @var{lst} is the\n"
"@var{previous} for the first call to @var{proc}.\n"
"\n"
"For example, the following adds a list of numbers, the calls\n"
"made to @code{+} are shown. (Of course @code{+} accepts\n"
"multiple arguments and can add a list directly, with\n"
"@code{apply}.)\n"
"\n"
"@example\n"
"(reduce + 0 '(5 6 7)) @result{} 18\n"
"\n"
"(+ 6 5) @result{} 11\n"
"(+ 7 11) @result{} 18\n"
"@end example\n"
"\n"
"@code{reduce} can be used instead of @code{fold} where the\n"
"@var{init} value is an ``identity'', meaning a value which\n"
"under @var{proc} doesn't change the result, in this case 0 is\n"
"an identity since @code{(+ 5 0)} is just 5. @code{reduce}\n"
"avoids that unnecessary call.")
#define FUNC_NAME s_scm_srfi1_reduce
{
scm_t_trampoline_2 proc_tramp = scm_trampoline_2 (proc);
SCM ret;
SCM_ASSERT (proc_tramp, proc, SCM_ARG1, FUNC_NAME);
ret = def; /* if lst is empty */
if (scm_is_pair (lst))
{
ret = SCM_CAR (lst); /* if lst has one element */
for (lst = SCM_CDR (lst); scm_is_pair (lst); lst = SCM_CDR (lst))
ret = proc_tramp (proc, SCM_CAR (lst), ret);
}
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG3, FUNC_NAME, "list");
return ret;
}
#undef FUNC_NAME
SCM_DEFINE (scm_srfi1_reduce_right, "reduce-right", 3, 0, 0,
(SCM proc, SCM def, SCM lst),
"@code{reduce-right} is a variant of @code{fold-right}, where\n"
"the first call to @var{proc} is on two elements from @var{lst},\n"
"rather than one element and a given initial value.\n"
"\n"
"If @var{lst} is empty, @code{reduce-right} returns @var{def}\n"
"(this is the only use for @var{def}). If @var{lst} has just\n"
"one element then that's the return value. Otherwise @var{proc}\n"
"is called on the elements of @var{lst}.\n"
"\n"
"Each @var{proc} call is @code{(@var{proc} @var{elem}\n"
"@var{previous})}, where @var{elem} is from @var{lst} (the\n"
"second last and then working back to the first element of\n"
"@var{lst}), and @var{previous} is the return from the previous\n"
"call to @var{proc}. The last element of @var{lst} is the\n"
"@var{previous} for the first call to @var{proc}.\n"
"\n"
"For example, the following adds a list of numbers, the calls\n"
"made to @code{+} are shown. (Of course @code{+} accepts\n"
"multiple arguments and can add a list directly, with\n"
"@code{apply}.)\n"
"\n"
"@example\n"
"(reduce-right + 0 '(5 6 7)) @result{} 18\n"
"\n"
"(+ 6 7) @result{} 13\n"
"(+ 5 13) @result{} 18\n"
"@end example\n"
"\n"
"@code{reduce-right} can be used instead of @code{fold-right}\n"
"where the @var{init} value is an ``identity'', meaning a value\n"
"which under @var{proc} doesn't change the result, in this case\n"
"0 is an identity since @code{(+ 7 0)} is just 5.\n"
"@code{reduce-right} avoids that unnecessary call.\n"
"\n"
"@code{reduce} should be preferred over @code{reduce-right} if\n"
"the order of processing doesn't matter, or can be arranged\n"
"either way, since @code{reduce} is a little more efficient.")
#define FUNC_NAME s_scm_srfi1_reduce_right
{
/* To work backwards across a list requires either repeatedly traversing
to get each previous element, or using some memory for a reversed or
random-access form. Repeated traversal might not be too terrible, but
is of course quadratic complexity and hence to be avoided in case LST
is long. A vector is preferred over a reversed list since it's more
compact and is less work for the gc to collect. */
scm_t_trampoline_2 proc_tramp = scm_trampoline_2 (proc);
SCM ret, vec;
long len, i;
SCM_ASSERT (proc_tramp, proc, SCM_ARG1, FUNC_NAME);
if (SCM_NULL_OR_NIL_P (lst))
return def;
vec = scm_vector (lst);
len = SCM_SIMPLE_VECTOR_LENGTH (vec);
ret = SCM_SIMPLE_VECTOR_REF (vec, len-1);
for (i = len-2; i >= 0; i--)
ret = proc_tramp (proc, SCM_SIMPLE_VECTOR_REF (vec, i), ret);
return ret;
}
#undef FUNC_NAME
SCM_DEFINE (scm_srfi1_remove, "remove", 2, 0, 0, SCM_DEFINE (scm_srfi1_remove, "remove", 2, 0, 0,
(SCM pred, SCM list), (SCM pred, SCM list),
"Return a list containing all elements from @var{lst} which do\n" "Return a list containing all elements from @var{lst} which do\n"
@ -1179,6 +1404,71 @@ SCM_DEFINE (scm_srfi1_remove_x, "remove!", 2, 0, 0,
#undef FUNC_NAME #undef FUNC_NAME
SCM_DEFINE (scm_srfi1_span, "span", 2, 0, 0,
(SCM pred, SCM lst),
"Return two values, the longest initial prefix of @var{lst}\n"
"whose elements all satisfy the predicate @var{pred}, and the\n"
"remainder of @var{lst}.")
#define FUNC_NAME s_scm_srfi1_span
{
scm_t_trampoline_1 pred_tramp;
SCM ret, *p;
pred_tramp = scm_trampoline_1 (pred);
SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
ret = SCM_EOL;
p = &ret;
for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
{
SCM elem = SCM_CAR (lst);
if (scm_is_false (pred_tramp (pred, elem)))
goto done;
/* want this elem, tack it onto the end of ret */
*p = scm_cons (elem, SCM_EOL);
p = SCM_CDRLOC (*p);
}
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG2, FUNC_NAME, "list");
done:
return scm_values (scm_list_2 (ret, lst));
}
#undef FUNC_NAME
SCM_DEFINE (scm_srfi1_span_x, "span!", 2, 0, 0,
(SCM pred, SCM lst),
"Return two values, the longest initial prefix of @var{lst}\n"
"whose elements all satisfy the predicate @var{pred}, and the\n"
"remainder of @var{lst}. @var{lst} may be modified to form the\n"
"return.")
#define FUNC_NAME s_scm_srfi1_span_x
{
SCM upto, *p;
scm_t_trampoline_1 pred_tramp;
pred_tramp = scm_trampoline_1 (pred);
SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
p = &lst;
for (upto = lst; scm_is_pair (upto); upto = SCM_CDR (upto))
{
if (scm_is_false (pred_tramp (pred, SCM_CAR (upto))))
goto done;
/* want this element */
p = SCM_CDRLOC (upto);
}
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (upto), lst, SCM_ARG2, FUNC_NAME, "list");
done:
*p = SCM_EOL;
return scm_values (scm_list_2 (lst, upto));
}
#undef FUNC_NAME
SCM_DEFINE (scm_srfi1_split_at, "split-at", 2, 0, 0, SCM_DEFINE (scm_srfi1_split_at, "split-at", 2, 0, 0,
(SCM lst, SCM n), (SCM lst, SCM n),
"Return two values (multiple values), being a list of the\n" "Return two values (multiple values), being a list of the\n"
@ -1230,6 +1520,34 @@ SCM_DEFINE (scm_srfi1_split_at_x, "split-at!", 2, 0, 0,
#undef FUNC_NAME #undef FUNC_NAME
SCM_DEFINE (scm_srfi1_take_x, "take!", 2, 0, 0,
(SCM lst, SCM n),
"Return a list containing the first @var{n} elements of\n"
"@var{lst}.")
#define FUNC_NAME s_scm_srfi1_take_x
{
long nn;
SCM pos;
SCM_VALIDATE_INUM_MIN_COPY (SCM_ARG2, n, 0, nn);
if (nn == 0)
return SCM_EOL;
pos = scm_list_tail (lst, SCM_I_MAKINUM (nn - 1));
/* Must have at least one cell left, mustn't have reached the end of an
n-1 element list. SCM_VALIDATE_CONS here gives the same error as
scm_list_tail does on say an n-2 element list, though perhaps a range
error would make more sense (for both). */
SCM_VALIDATE_CONS (SCM_ARG1, pos);
SCM_SETCDR (pos, SCM_EOL);
return lst;
}
#undef FUNC_NAME
SCM_DEFINE (scm_srfi1_take_right, "take-right", 2, 0, 0, SCM_DEFINE (scm_srfi1_take_right, "take-right", 2, 0, 0,
(SCM lst, SCM n), (SCM lst, SCM n),
"Return the a list containing the @var{n} last elements of\n" "Return the a list containing the @var{n} last elements of\n"
@ -1248,6 +1566,69 @@ SCM_DEFINE (scm_srfi1_take_right, "take-right", 2, 0, 0,
#undef FUNC_NAME #undef FUNC_NAME
SCM_DEFINE (scm_srfi1_take_while, "take-while", 2, 0, 0,
(SCM pred, SCM lst),
"Return a new list which is the longest initial prefix of\n"
"@var{lst} whose elements all satisfy the predicate @var{pred}.")
#define FUNC_NAME s_scm_srfi1_take_while
{
scm_t_trampoline_1 pred_tramp;
SCM ret, *p;
pred_tramp = scm_trampoline_1 (pred);
SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
ret = SCM_EOL;
p = &ret;
for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
{
SCM elem = SCM_CAR (lst);
if (scm_is_false (pred_tramp (pred, elem)))
goto done;
/* want this elem, tack it onto the end of ret */
*p = scm_cons (elem, SCM_EOL);
p = SCM_CDRLOC (*p);
}
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG2, FUNC_NAME, "list");
done:
return ret;
}
#undef FUNC_NAME
SCM_DEFINE (scm_srfi1_take_while_x, "take-while!", 2, 0, 0,
(SCM pred, SCM lst),
"Return the longest initial prefix of @var{lst} whose elements\n"
"all satisfy the predicate @var{pred}. @var{lst} may be\n"
"modified to form the return.")
#define FUNC_NAME s_scm_srfi1_take_while_x
{
SCM upto, *p;
scm_t_trampoline_1 pred_tramp;
pred_tramp = scm_trampoline_1 (pred);
SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
p = &lst;
for (upto = lst; scm_is_pair (upto); upto = SCM_CDR (upto))
{
if (scm_is_false (pred_tramp (pred, SCM_CAR (upto))))
goto done;
/* want this element */
p = SCM_CDRLOC (upto);
}
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (upto), lst, SCM_ARG2, FUNC_NAME, "list");
done:
*p = SCM_EOL;
return lst;
}
#undef FUNC_NAME
void void
scm_init_srfi_1 (void) scm_init_srfi_1 (void)
{ {

View file

@ -41,10 +41,13 @@ SCM_SRFI1_API SCM scm_srfi1_delete_x (SCM x, SCM lst, SCM pred);
SCM_SRFI1_API SCM scm_srfi1_delete_duplicates (SCM lst, SCM pred); SCM_SRFI1_API SCM scm_srfi1_delete_duplicates (SCM lst, SCM pred);
SCM_SRFI1_API SCM scm_srfi1_delete_duplicates_x (SCM lst, SCM pred); SCM_SRFI1_API SCM scm_srfi1_delete_duplicates_x (SCM lst, SCM pred);
SCM_SRFI1_API SCM scm_srfi1_drop_right (SCM lst, SCM n); SCM_SRFI1_API SCM scm_srfi1_drop_right (SCM lst, SCM n);
SCM_SRFI1_API SCM scm_srfi1_drop_right_x (SCM lst, SCM n);
SCM_SRFI1_API SCM scm_srfi1_drop_while (SCM pred, SCM lst);
SCM_SRFI1_API SCM scm_srfi1_filter_map (SCM proc, SCM list1, SCM rest); SCM_SRFI1_API SCM scm_srfi1_filter_map (SCM proc, SCM list1, SCM rest);
SCM_SRFI1_API SCM scm_srfi1_find (SCM pred, SCM lst); SCM_SRFI1_API SCM scm_srfi1_find (SCM pred, SCM lst);
SCM_SRFI1_API SCM scm_srfi1_find_tail (SCM pred, SCM lst); SCM_SRFI1_API SCM scm_srfi1_find_tail (SCM pred, SCM lst);
SCM_SRFI1_API SCM scm_srfi1_length_plus (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_list_copy (SCM lst); SCM_SRFI1_API SCM scm_srfi1_list_copy (SCM lst);
SCM_SRFI1_API SCM scm_srfi1_map (SCM proc, SCM arg1, SCM args); SCM_SRFI1_API SCM scm_srfi1_map (SCM proc, SCM arg1, SCM args);
SCM_SRFI1_API SCM scm_srfi1_for_each (SCM proc, SCM arg1, SCM args); SCM_SRFI1_API SCM scm_srfi1_for_each (SCM proc, SCM arg1, SCM args);
@ -52,11 +55,18 @@ SCM_SRFI1_API SCM scm_srfi1_member (SCM obj, SCM ls, SCM pred);
SCM_SRFI1_API SCM scm_srfi1_assoc (SCM key, SCM alist, SCM pred); SCM_SRFI1_API SCM scm_srfi1_assoc (SCM key, SCM alist, SCM pred);
SCM_SRFI1_API SCM scm_srfi1_partition (SCM pred, SCM list); SCM_SRFI1_API SCM scm_srfi1_partition (SCM pred, SCM list);
SCM_SRFI1_API SCM scm_srfi1_partition_x (SCM pred, SCM list); SCM_SRFI1_API SCM scm_srfi1_partition_x (SCM pred, SCM list);
SCM_SRFI1_API SCM scm_srfi1_reduce (SCM proc, SCM def, SCM lst);
SCM_SRFI1_API SCM scm_srfi1_reduce_right (SCM proc, SCM def, SCM lst);
SCM_SRFI1_API SCM scm_srfi1_remove (SCM pred, SCM list); SCM_SRFI1_API SCM scm_srfi1_remove (SCM pred, SCM list);
SCM_SRFI1_API SCM scm_srfi1_remove_x (SCM pred, SCM list); SCM_SRFI1_API SCM scm_srfi1_remove_x (SCM pred, SCM list);
SCM_SRFI1_API SCM scm_srfi1_span (SCM pred, SCM lst);
SCM_SRFI1_API SCM scm_srfi1_span_x (SCM pred, SCM lst);
SCM_SRFI1_API SCM scm_srfi1_split_at (SCM lst, SCM n); SCM_SRFI1_API SCM scm_srfi1_split_at (SCM lst, SCM n);
SCM_SRFI1_API SCM scm_srfi1_split_at_x (SCM lst, SCM n); SCM_SRFI1_API SCM scm_srfi1_split_at_x (SCM lst, SCM n);
SCM_SRFI1_API SCM scm_srfi1_take_x (SCM lst, SCM n);
SCM_SRFI1_API SCM scm_srfi1_take_right (SCM lst, SCM n); SCM_SRFI1_API SCM scm_srfi1_take_right (SCM lst, SCM n);
SCM_SRFI1_API SCM scm_srfi1_take_while (SCM pred, SCM lst);
SCM_SRFI1_API SCM scm_srfi1_take_while_x (SCM pred, SCM lst);
SCM_SRFI1_API void scm_init_srfi_1 (void); SCM_SRFI1_API void scm_init_srfi_1 (void);