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73 lines
1.4 KiB
C

/* $Revision: 1.5 $
*/
/* Functions that maintain a properly GC-linked list of Scheme
* arguments. The parser collects arguments to an event procedure
* using args_add(); the code that eventually calls the event
* procedure calls args_get() to obtain a list of arguments that
* can directly be passed to Funcall().
*
* args_clear() -- clears the list
* args_add(obj) -- appends an object to the list
* args_get() -- returns the list
* args_num() -- returns the current length of the list
*/
#include "unroff.h"
static Object args, last, rest;
static int num;
void args_clear(void) {
if (Nullp(last)) {
if (!Nullp(rest))
args = rest;
} else
P_Setcdr(last, rest);
last = Null;
num = 0;
}
void args_add(Object x) {
Object tmp;
GC_Node;
if (Nullp(last)) {
last = args;
} else {
if (Nullp(Cdr(last))) {
GC_Link(x);
tmp = Cons(False, Null);
GC_Unlink;
Cdr(last) = tmp;
}
last = Cdr(last);
}
Car(last) = x;
rest = Cdr(last);
num++;
}
Object args_get(void) {
if (Nullp(last)) {
rest = args;
return Null;
}
rest = Cdr(last);
P_Setcdr(last, Null);
return args;
}
int args_num(void) {
return num;
}
void init_args(void) {
rest = Cons(False, Null);
args = last = Null;
Global_GC_Link(args);
Global_GC_Link(last);
Global_GC_Link(rest);
}