99 lines
1.7 KiB
R
99 lines
1.7 KiB
R
#include "string.h"
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#include "Cons.h"
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#include "Nil.h"
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#include "defs.h"
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#include "SchemeString.h"
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Cons *cons (SchemeObject *car, SchemeObject *cdr)
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{
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return [Cons newWithCar: car cdr: cdr];
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}
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integer length (SchemeObject *foo)
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{
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local integer len;
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for (len = 0; [foo isKindOfClass: [Cons class]]; foo = [(Cons *) foo cdr]) {
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len++;
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}
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return len;
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}
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BOOL isList (SchemeObject *ls)
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{
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return ls == [Nil nil] ||
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([ls isKindOfClass: [Cons class]] &&
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isList([(Cons*) ls cdr]));
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}
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@implementation Cons
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+ (id) newWithCar: (SchemeObject *) a cdr: (SchemeObject *) d
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{
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return [[self alloc] initWithCar: a cdr: d];
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}
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- (id) initWithCar: (SchemeObject *) a cdr: (SchemeObject *) d
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{
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car = a;
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cdr = d;
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if (!car) {
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print("Cons: WARNING: nil car\n");
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} else if (!cdr) {
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print("cons: WARNING: nil cdr\n");
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}
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return [super init];
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}
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- (SchemeObject *) car
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{
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return car;
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}
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- (void) car: (SchemeObject *) a
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{
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car = a;
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}
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- (SchemeObject *) cdr
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{
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return cdr;
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}
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- (void) cdr: (SchemeObject *) d
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{
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cdr = d;
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}
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- (void) markReachable
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{
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[car mark];
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[cdr mark];
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}
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- (string) printForm
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{
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local string acc = "";
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local id cur, next = nil;
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for (cur = self; cur; cur = next) {
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next = [cur cdr];
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acc = acc + [[cur car] printForm];
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if (next == [Nil nil]) {
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next = nil;
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} else if (next && ![next isKindOfClass: [Cons class]]) {
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acc = acc + " . " + [next printForm];
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next = nil;
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} else if (next) {
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acc = acc + " ";
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}
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}
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return [[String newFromString: sprintf("(%s)", acc)] stringValue];
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}
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@end
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