upscheme/tiny/scrap.c

108 lines
2.8 KiB
C

// code to relocate cons chains iteratively
pcdr = &cdr_(nc);
while (iscons(d)) {
if (car_(d) == FWD) {
*pcdr = cdr_(d);
return first;
}
*pcdr = nc = mk_cons();
a = car_(d); v = cdr_(d);
car_(d) = FWD; cdr_(d) = nc;
car_(nc) = relocate(a);
pcdr = &cdr_(nc);
d = v;
}
*pcdr = d;
/*
f = *rest;
*rest = NIL;
while (iscons(f)) { // nreverse!
v = cdr_(f);
cdr_(f) = *rest;
*rest = f;
f = v;
}*/
int favailable(FILE *f)
{
fd_set set;
struct timeval tv = {0, 0};
int fd = fileno(f);
FD_ZERO(&set);
FD_SET(fd, &set);
return (select(fd+1, &set, NULL, NULL, &tv)!=0);
}
static void print_env(value_t *penv)
{
printf("<[ ");
while (issymbol(*penv) && *penv!=NIL) {
print(stdout, *penv, 0);
printf(" ");
penv++;
print(stdout, *penv, 0);
printf(" ");
penv++;
}
printf("] ");
print(stdout, *penv, 0);
printf(">\n");
}
#else
PUSH(NIL);
PUSH(NIL);
value_t *rest = &Stack[SP-1];
// build list of rest arguments
// we have to build it forwards, which is tricky
while (iscons(v)) {
v = eval(car_(v));
PUSH(v);
v = cons_(&Stack[SP-1], &NIL);
POP();
if (iscons(*rest))
cdr_(*rest) = v;
else
Stack[SP-2] = v;
*rest = v;
v = Stack[saveSP] = cdr_(Stack[saveSP]);
}
POP();
#endif
// this version uses collective allocation. about 7-10%
// faster for lists with > 2 elements, but uses more
// stack space
i = SP;
while (iscons(v)) {
v = eval(car_(v));
PUSH(v);
v = Stack[saveSP] = cdr_(Stack[saveSP]);
}
if ((int)SP==i) {
PUSH(NIL);
}
else {
e = v = cons_reserve(nargs=(SP-i));
for(; i < (int)SP; i++) {
car_(v) = Stack[i];
v = cdr_(v);
}
POPN(nargs);
PUSH(e);
}
value_t list_to_vector(value_t l)
{
value_t v;
size_t n = llength(l), i=0;
v = alloc_vector(n, 0);
while (iscons(l)) {
vector_elt(v,i) = car_(l);
i++;
l = cdr_(l);
}
return v;
}