/* Look for an iterate-over-plot construct, of the form
* {s}plot for [<var> = <start> : <end> { : <increment>}] ...
*/
void
check_for_iteration()
{
char *errormsg = "Expecting iterator \tfor [<var> = <start> : <end>]\n\t\t\tor\tfor [<var> in \"string of words\"]";
iteration_udv = NULL;
free(iteration_string);
iteration_string = NULL;
iteration_increment = 1;
iteration = 0;
if (!equals(c_token, "for"))
return;
c_token++;
if (!equals(c_token++, "[") || !isletter(c_token))
int_error(c_token-1, errormsg);
iteration_udv = add_udv(c_token++);
if (equals(c_token, "=")) {
c_token++;
iteration_start = int_expression();
if (!equals(c_token++, ":"))
int_error(c_token-1, errormsg);
iteration_end = int_expression();
if (equals(c_token,":")) {
c_token++;
iteration_increment = int_expression();
}
if (!equals(c_token++, "]"))
int_error(c_token-1, errormsg);
if (iteration_udv->udv_undef == FALSE)
gpfree_string(&iteration_udv->udv_value);
Ginteger(&(iteration_udv->udv_value), iteration_start);
iteration_udv->udv_undef = FALSE;
}
else if (equals(c_token++, "in")) {
iteration_string = try_to_get_string();
if (!iteration_string)
int_error(c_token-1, errormsg);
if (!equals(c_token++, "]"))
int_error(c_token-1, errormsg);
iteration_start = 1;
iteration_end = gp_words(iteration_string);
if (iteration_udv->udv_undef == FALSE)
gpfree_string(&iteration_udv->udv_value);
Gstring(&(iteration_udv->udv_value), gp_word(iteration_string, 1));
iteration_udv->udv_undef = FALSE;
}
else /* Neither [i=B:E] or [s in "foo"] */
int_error(c_token-1, errormsg);
iteration_current = iteration_start;
}
/* Look for iterate-over-plot constructs, of the form
* for [<var> = <start> : <end> { : <increment>}] ...
* If one (or more) is found, an iterator structure is allocated and filled
* and a pointer to that structure is returned.
* The pointer is NULL if no "for" statements are found.
*/
t_iterator *
check_for_iteration()
{
char *errormsg = "Expecting iterator \tfor [<var> = <start> : <end> {: <incr>}]\n\t\t\tor\tfor [<var> in \"string of words\"]";
int nesting_depth = 0;
t_iterator *iter = NULL;
t_iterator *this_iter = NULL;
/* Now checking for iteration parameters */
/* Nested "for" statements are supported, each one corresponds to a node of the linked list */
while (equals(c_token, "for")) {
struct udvt_entry *iteration_udv = NULL;
char *iteration_string = NULL;
int iteration_start;
int iteration_end;
int iteration_increment = 1;
int iteration_current;
int iteration = 0;
TBOOLEAN empty_iteration;
TBOOLEAN just_once = FALSE;
c_token++;
if (!equals(c_token++, "[") || !isletter(c_token))
int_error(c_token-1, errormsg);
iteration_udv = add_udv(c_token++);
if (equals(c_token, "=")) {
c_token++;
iteration_start = int_expression();
if (!equals(c_token++, ":"))
int_error(c_token-1, errormsg);
iteration_end = int_expression();
if (equals(c_token,":")) {
c_token++;
iteration_increment = int_expression();
if (iteration_increment == 0)
int_error(c_token-1, errormsg);
}
if (!equals(c_token++, "]"))
int_error(c_token-1, errormsg);
if (iteration_udv->udv_undef == FALSE)
gpfree_string(&(iteration_udv->udv_value));
Ginteger(&(iteration_udv->udv_value), iteration_start);
iteration_udv->udv_undef = FALSE;
}
else if (equals(c_token++, "in")) {
iteration_string = try_to_get_string();
if (!iteration_string)
int_error(c_token-1, errormsg);
if (!equals(c_token++, "]"))
int_error(c_token-1, errormsg);
iteration_start = 1;
iteration_end = gp_words(iteration_string);
if (iteration_udv->udv_undef == FALSE)
gpfree_string(&(iteration_udv->udv_value));
Gstring(&(iteration_udv->udv_value), gp_word(iteration_string, 1));
iteration_udv->udv_undef = FALSE;
}
else /* Neither [i=B:E] or [s in "foo"] */
int_error(c_token-1, errormsg);
iteration_current = iteration_start;
empty_iteration = FALSE;
if ( (iteration_udv != NULL)
&& ((iteration_end > iteration_start && iteration_increment < 0)
|| (iteration_end < iteration_start && iteration_increment > 0))) {
empty_iteration = TRUE;
FPRINTF((stderr,"Empty iteration\n"));
}
/* Allocating a node of the linked list nested iterations. */
/* Iterating just once is the same as not iterating at all */
/* so we skip building the node in that case. */
if (iteration_start == iteration_end)
just_once = TRUE;
if (iteration_start < iteration_end && iteration_end < iteration_start + iteration_increment)
just_once = TRUE;
if (iteration_start > iteration_end && iteration_end > iteration_start + iteration_increment)
just_once = TRUE;
if (!just_once) {
this_iter = gp_alloc(sizeof(t_iterator), "iteration linked list");
this_iter->iteration_udv = iteration_udv;
this_iter->iteration_string = iteration_string;
this_iter->iteration_start = iteration_start;
this_iter->iteration_end = iteration_end;
this_iter->iteration_increment = iteration_increment;
this_iter->iteration_current = iteration_current;
this_iter->iteration = iteration;
this_iter->done = FALSE;
this_iter->really_done = FALSE;
this_iter->empty_iteration = empty_iteration;
this_iter->next = NULL;
this_iter->prev = NULL;
if (nesting_depth == 0) {
/* first "for" statement: this will be the listhead */
iter = this_iter;
}
else {
/* not the first "for" statement: attach the newly created node to the end of the list */
iter->prev->next = this_iter; /* iter->prev points to the last node of the list */
this_iter->prev = iter->prev;
}
iter->prev = this_iter; /* a shortcut: making the list circular */
/* if one iteration in the chain is empty, the subchain of nested iterations is too */
if (!iter->empty_iteration)
iter->empty_iteration = empty_iteration;
nesting_depth++;
}
}
return iter;
}
