X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=src%2Flisp%2Fao_lisp_eval.c;h=e3d653b99e1635e078967db28d84cf3a8ee26475;hb=d8cf97fe22acefab40d7bb321138e46d4483fef7;hp=5e4908ffdf0ddb8fa0f86a3dbf4ede23ce91b75a;hpb=c9456362c8bad8cd9be717f591f2d0841f88eb50;p=fw%2Faltos

diff --git a/src/lisp/ao_lisp_eval.c b/src/lisp/ao_lisp_eval.c
index 5e4908ff..e3d653b9 100644
--- a/src/lisp/ao_lisp_eval.c
+++ b/src/lisp/ao_lisp_eval.c
@@ -14,13 +14,14 @@
 
 #include "ao_lisp.h"
 
-#if 1
+#if 0
+#define DBG_CODE	1
 static int stack_depth;
 #define DBG_INDENT()	do { int _s; for(_s = 0; _s < stack_depth; _s++) printf("  "); } while(0)
 #define DBG_IN()	(++stack_depth)
 #define DBG_OUT()	(--stack_depth)
 #define DBG(...) 	printf(__VA_ARGS__)
-#define DBGI(...)	do { DBG_INDENT(); DBG(__VA_ARGS__); } while (0)
+#define DBGI(...)	do { DBG_INDENT(); DBG("%4d: ", __LINE__); DBG(__VA_ARGS__); } while (0)
 #define DBG_CONS(a)	ao_lisp_cons_print(ao_lisp_cons_poly(a))
 #define DBG_POLY(a)	ao_lisp_poly_print(a)
 #define OFFSET(a)	((a) ? (int) ((uint8_t *) a - ao_lisp_pool) : -1)
@@ -37,13 +38,17 @@ static int stack_depth;
 enum eval_state {
 	eval_sexpr,
 	eval_val,
+	eval_formal,
 	eval_exec,
-	eval_exec_direct
+	eval_exec_direct,
+	eval_cond,
+	eval_cond_test
 };
 
 struct ao_lisp_stack {
 	ao_poly			prev;
 	uint8_t			state;
+	uint8_t			macro;
 	ao_poly			actuals;
 	ao_poly			formals;
 	ao_poly			formals_tail;
@@ -76,6 +81,7 @@ stack_mark(void *addr)
 	for (;;) {
 		ao_lisp_poly_mark(stack->actuals);
 		ao_lisp_poly_mark(stack->formals);
+		/* no need to mark formals_tail */
 		ao_lisp_poly_mark(stack->frame);
 		stack = ao_lisp_poly_stack(stack->prev);
 		if (ao_lisp_mark_memory(stack, sizeof (struct ao_lisp_stack)))
@@ -83,20 +89,51 @@ stack_mark(void *addr)
 	}
 }
 
+static const struct ao_lisp_type ao_lisp_stack_type;
+
+#if DBG_CODE
+static void
+stack_validate_tail(struct ao_lisp_stack *stack)
+{
+	struct ao_lisp_cons *head = ao_lisp_poly_cons(stack->formals);
+	struct ao_lisp_cons *tail = ao_lisp_poly_cons(stack->formals_tail);
+	struct ao_lisp_cons *cons;
+	for (cons = head; cons && cons->cdr && cons != tail; cons = ao_lisp_poly_cons(cons->cdr))
+		;
+	if (cons != tail || (tail && tail->cdr)) {
+		if (!tail) {
+			printf("tail null\n");
+		} else {
+			printf("tail validate fail head %d actual %d recorded %d\n",
+			       OFFSET(head), OFFSET(cons), OFFSET(tail));
+			abort();
+		}
+	}
+}
+#else
+#define stack_validate_tail(s)
+#endif
+
 static void
 stack_move(void *addr)
 {
 	struct ao_lisp_stack	*stack = addr;
 
-	for (;;) {
-		struct ao_lisp_stack *prev;
-		stack->actuals = ao_lisp_poly_move(stack->actuals);
-		stack->formals = ao_lisp_poly_move(stack->formals);
-		stack->frame = ao_lisp_poly_move(stack->frame);
-		prev = ao_lisp_ref(stack->prev);
-		prev = ao_lisp_move_memory(prev, sizeof (struct ao_lisp_stack));
-		stack->prev = ao_lisp_stack_poly(prev);
-		stack = prev;
+	while (stack) {
+		void	*prev;
+		int	ret;
+		(void) ao_lisp_poly_move(&stack->actuals);
+		(void) ao_lisp_poly_move(&stack->formals);
+		(void) ao_lisp_poly_move(&stack->formals_tail);
+		(void) ao_lisp_poly_move(&stack->frame);
+		prev = ao_lisp_poly_stack(stack->prev);
+		ret = ao_lisp_move(&ao_lisp_stack_type, &prev);
+		if (prev != ao_lisp_poly_stack(stack->prev))
+			stack->prev = ao_lisp_stack_poly(prev);
+		stack_validate_tail(stack);
+		if (ret)
+			break;
+		stack = ao_lisp_poly_stack(stack->prev);
 	}
 }
 
@@ -106,45 +143,69 @@ static const struct ao_lisp_type ao_lisp_stack_type = {
 	.move = stack_move
 };
 
-
 static struct ao_lisp_stack	*ao_lisp_stack;
+static ao_poly			ao_lisp_v;
 static uint8_t been_here;
 
+#if DBG_CODE
+static void
+stack_validate_tails(void)
+{
+	struct ao_lisp_stack	*stack;
+
+	for (stack = ao_lisp_stack; stack; stack = ao_lisp_poly_stack(stack->prev))
+		stack_validate_tail(stack);
+}
+#else
+#define stack_validate_tails(s)
+#endif
+
 ao_poly
 ao_lisp_set_cond(struct ao_lisp_cons *c)
 {
+	ao_lisp_stack->state = eval_cond;
+	ao_lisp_stack->actuals = ao_lisp_cons_poly(c);
 	return AO_LISP_NIL;
 }
 
-static void
+void
 ao_lisp_stack_reset(struct ao_lisp_stack *stack)
 {
 	stack->state = eval_sexpr;
+	stack->macro = 0;
 	stack->actuals = AO_LISP_NIL;
 	stack->formals = AO_LISP_NIL;
 	stack->formals_tail = AO_LISP_NIL;
 	stack->frame = ao_lisp_frame_poly(ao_lisp_frame_current);
+	stack_validate_tails();
 }
 
-static struct ao_lisp_stack *
+int
 ao_lisp_stack_push(void)
 {
+	stack_validate_tails();
+	if (ao_lisp_stack) {
+		DBGI("formals "); DBG_POLY(ao_lisp_stack->formals); DBG("\n");
+		DBGI("actuals "); DBG_POLY(ao_lisp_stack->actuals); DBG("\n");
+	}
+	DBGI("stack push\n");
+	DBG_IN();
 	struct ao_lisp_stack	*stack = ao_lisp_alloc(sizeof (struct ao_lisp_stack));
 	if (!stack)
-		return NULL;
+		return 0;
 	stack->prev = ao_lisp_stack_poly(ao_lisp_stack);
-	ao_lisp_stack_reset(stack);
 	ao_lisp_stack = stack;
-	DBGI("stack push\n");
-	DBG_IN();
-	return stack;
+	ao_lisp_stack_reset(stack);
+	stack_validate_tails();
+	return 1;
 }
 
-static struct ao_lisp_stack *
+void
 ao_lisp_stack_pop(void)
 {
 	if (!ao_lisp_stack)
-		return NULL;
+		return;
+	stack_validate_tails();
 	DBG_OUT();
 	DBGI("stack pop\n");
 	ao_lisp_stack = ao_lisp_poly_stack(ao_lisp_stack->prev);
@@ -152,17 +213,20 @@ ao_lisp_stack_pop(void)
 		ao_lisp_frame_current = ao_lisp_poly_frame(ao_lisp_stack->frame);
 	else
 		ao_lisp_frame_current = NULL;
-	return ao_lisp_stack;
+	if (ao_lisp_stack) {
+		DBGI("formals "); DBG_POLY(ao_lisp_stack->formals); DBG("\n");
+		DBGI("actuals "); DBG_POLY(ao_lisp_stack->actuals); DBG("\n");
+	}
 }
 
 static void
 ao_lisp_stack_clear(void)
 {
+	stack_validate_tails();
 	ao_lisp_stack = NULL;
 	ao_lisp_frame_current = NULL;
 }
 
-
 static ao_poly
 func_type(ao_poly func)
 {
@@ -194,8 +258,11 @@ func_type(ao_poly func)
 			f++;
 		}
 		return ao_lisp_arg(cons, 0);
-	} else
-		return ao_lisp_error(AO_LISP_INVALID, "not a func");
+	} else {
+		ao_lisp_error(AO_LISP_INVALID, "not a func");
+		abort();
+		return AO_LISP_NIL;
+	}
 }
 
 static int
@@ -234,8 +301,8 @@ ao_lisp_lambda(struct ao_lisp_cons *cons)
 		args_provided = 1;
 	if (args_wanted != args_provided)
 		return ao_lisp_error(AO_LISP_INVALID, "need %d args, not %d", args_wanted, args_provided);
-	next_frame = ao_lisp_frame_new(args_wanted, 0);
-	DBGI("new frame %d\n", OFFSET(next_frame));
+	next_frame = ao_lisp_frame_new(args_wanted);
+//	DBGI("new frame %d\n", OFFSET(next_frame));
 	switch (type) {
 	case _ao_lisp_atom_lambda: {
 		int			f;
@@ -266,331 +333,177 @@ ao_lisp_lambda(struct ao_lisp_cons *cons)
 }
 
 ao_poly
-ao_lisp_eval(ao_poly v)
+ao_lisp_eval(ao_poly _v)
 {
-	struct ao_lisp_stack	*stack;
 	ao_poly			formal;
 
+	ao_lisp_v = _v;
 	if (!been_here) {
 		been_here = 1;
-		ao_lisp_root_add(&ao_lisp_stack_type, &stack);
+		ao_lisp_root_add(&ao_lisp_stack_type, &ao_lisp_stack);
+		ao_lisp_root_poly_add(&ao_lisp_v);
 	}
 
-	stack = ao_lisp_stack_push();
+	if (!ao_lisp_stack_push())
+		goto bail;
 
 	for (;;) {
 		if (ao_lisp_exception)
-			return AO_LISP_NIL;
-		switch (stack->state) {
+			goto bail;
+		switch (ao_lisp_stack->state) {
 		case eval_sexpr:
-			DBGI("sexpr: "); DBG_POLY(v); DBG("\n");
-			switch (ao_lisp_poly_type(v)) {
+			DBGI("sexpr: "); DBG_POLY(ao_lisp_v); DBG("\n");
+			switch (ao_lisp_poly_type(ao_lisp_v)) {
 			case AO_LISP_CONS:
-				if (v == AO_LISP_NIL) {
-					stack->state = eval_exec;
+				if (ao_lisp_v == AO_LISP_NIL) {
+					ao_lisp_stack->state = eval_exec;
 					break;
 				}
-				stack->actuals = v;
-				stack = ao_lisp_stack_push();
-				v = ao_lisp_poly_cons(v)->car;
+				ao_lisp_stack->actuals = ao_lisp_v;
+				DBGI("actuals now "); DBG_POLY(ao_lisp_v); DBG("\n");
+				ao_lisp_stack->state = eval_formal;
+				if (!ao_lisp_stack_push())
+					goto bail;
+				ao_lisp_v = ao_lisp_poly_cons(ao_lisp_v)->car;
+				stack_validate_tails();
 				break;
 			case AO_LISP_ATOM:
-				v = ao_lisp_atom_get(v);
+				ao_lisp_v = ao_lisp_atom_get(ao_lisp_v);
 				/* fall through */
 			case AO_LISP_INT:
 			case AO_LISP_STRING:
-				stack->state = eval_val;
+			case AO_LISP_BUILTIN:
+				ao_lisp_stack->state = eval_val;
 				break;
 			}
 			break;
 		case eval_val:
-			DBGI("val: "); DBG_POLY(v); DBG("\n");
-			stack = ao_lisp_stack_pop();
-			if (!stack)
-				return v;
+			DBGI("val: "); DBG_POLY(ao_lisp_v); DBG("\n");
+			ao_lisp_stack_pop();
+			if (!ao_lisp_stack)
+				return ao_lisp_v;
+			DBGI("..state %d\n", ao_lisp_stack->state);
+			break;
 
-			stack->state = eval_sexpr;
+		case eval_formal:
 			/* Check what kind of function we've got */
-			if (!stack->formals) {
-				switch (func_type(v)) {
+			if (!ao_lisp_stack->formals) {
+				switch (func_type(ao_lisp_v)) {
 				case AO_LISP_LAMBDA:
 				case _ao_lisp_atom_lambda:
 				case AO_LISP_LEXPR:
 				case _ao_lisp_atom_lexpr:
 					DBGI(".. lambda or lexpr\n");
 					break;
-				case AO_LISP_NLAMBDA:
-				case _ao_lisp_atom_nlambda:
 				case AO_LISP_MACRO:
 				case _ao_lisp_atom_macro:
+					ao_lisp_stack->macro = 1;
+				case AO_LISP_NLAMBDA:
+				case _ao_lisp_atom_nlambda:
 					DBGI(".. nlambda or macro\n");
-					stack->formals = stack->actuals;
-					stack->state = eval_exec_direct;
+					ao_lisp_stack->formals = ao_lisp_stack->actuals;
+					ao_lisp_stack->formals_tail = AO_LISP_NIL;
+					ao_lisp_stack->state = eval_exec_direct;
+					stack_validate_tails();
 					break;
 				}
-				if (stack->state == eval_exec_direct)
+				if (ao_lisp_stack->state == eval_exec_direct)
 					break;
 			}
 
-			formal = ao_lisp_cons_poly(ao_lisp_cons_cons(v, NULL));
-			if (!formal) {
-				ao_lisp_stack_clear();
-				return AO_LISP_NIL;
-			}
+			DBGI("add formal "); DBG_POLY(ao_lisp_v); DBG("\n");
+			stack_validate_tails();
+			formal = ao_lisp_cons_poly(ao_lisp_cons_cons(ao_lisp_v, NULL));
+			stack_validate_tails();
+			if (!formal)
+				goto bail;
 
-			if (stack->formals_tail)
-				ao_lisp_poly_cons(stack->formals_tail)->cdr = formal;
+			if (ao_lisp_stack->formals_tail)
+				ao_lisp_poly_cons(ao_lisp_stack->formals_tail)->cdr = formal;
 			else
-				stack->formals = formal;
-			stack->formals_tail = formal;
+				ao_lisp_stack->formals = formal;
+			ao_lisp_stack->formals_tail = formal;
+
+			DBGI("formals now "); DBG_POLY(ao_lisp_stack->formals); DBG("\n");
 
-			DBGI("formals now "); DBG_POLY(stack->formals); DBG("\n");
+			ao_lisp_v = ao_lisp_poly_cons(ao_lisp_stack->actuals)->cdr;
 
-			v = ao_lisp_poly_cons(stack->actuals)->cdr;
+			stack_validate_tails();
+			ao_lisp_stack->state = eval_sexpr;
 
 			break;
 		case eval_exec:
-			v = ao_lisp_poly_cons(stack->formals)->car;
+			if (!ao_lisp_stack->formals) {
+				ao_lisp_v = AO_LISP_NIL;
+				ao_lisp_stack->state = eval_val;
+				break;
+			}
+			ao_lisp_v = ao_lisp_poly_cons(ao_lisp_stack->formals)->car;
 		case eval_exec_direct:
-			DBGI("exec: "); DBG_POLY(v); DBG(" formals "); DBG_POLY(stack->formals); DBG ("\n");
-			if (ao_lisp_poly_type(v) == AO_LISP_BUILTIN) {
-				struct ao_lisp_builtin *b = ao_lisp_poly_builtin(v);
-
-				v = ao_lisp_func(b) (ao_lisp_poly_cons(ao_lisp_poly_cons(stack->formals)->cdr));
-				DBGI("builtin result:"); DBG_POLY(v); DBG ("\n");
-				if (ao_lisp_exception) {
-					ao_lisp_stack_clear();
-					return AO_LISP_NIL;
-				}
-				stack->state = eval_val;
+			DBGI("exec: macro %d ", ao_lisp_stack->macro); DBG_POLY(ao_lisp_v); DBG(" formals "); DBG_POLY(ao_lisp_stack->formals); DBG ("\n");
+			if (ao_lisp_poly_type(ao_lisp_v) == AO_LISP_BUILTIN) {
+				stack_validate_tails();
+				struct ao_lisp_builtin	*b = ao_lisp_poly_builtin(ao_lisp_v);
+				stack_validate_tails();
+				struct ao_lisp_cons	*f = ao_lisp_poly_cons(ao_lisp_poly_cons(ao_lisp_stack->formals)->cdr);
+
+				DBGI(".. builtin formals "); DBG_CONS(f); DBG("\n");
+				stack_validate_tails();
+				if (ao_lisp_stack->macro)
+					ao_lisp_stack->state = eval_sexpr;
+				else
+					ao_lisp_stack->state = eval_val;
+				ao_lisp_stack->macro = 0;
+				ao_lisp_stack->actuals = ao_lisp_stack->formals = ao_lisp_stack->formals_tail = AO_LISP_NIL;
+				ao_lisp_v = ao_lisp_func(b) (f);
+				DBGI("builtin result:"); DBG_POLY(ao_lisp_v); DBG ("\n");
+				if (ao_lisp_exception)
+					goto bail;
 				break;
 			} else {
-				v = ao_lisp_lambda(ao_lisp_poly_cons(stack->formals));
-				ao_lisp_stack_reset(stack);
+				ao_lisp_v = ao_lisp_lambda(ao_lisp_poly_cons(ao_lisp_stack->formals));
+				ao_lisp_stack_reset(ao_lisp_stack);
 			}
 			break;
-		}
-	}
-}
-#if 0
-
-
-	restart:
-		if (cond) {
-			DBGI("cond is now "); DBG_CONS(cond); DBG("\n");
-			if (cond->car == AO_LISP_NIL) {
-				cond = AO_LISP_NIL;
-				v = AO_LISP_NIL;
+		case eval_cond:
+			DBGI("cond: "); DBG_POLY(ao_lisp_stack->actuals); DBG("\n");
+			if (!ao_lisp_stack->actuals) {
+				ao_lisp_v = AO_LISP_NIL;
+				ao_lisp_stack->state = eval_val;
 			} else {
-				if (ao_lisp_poly_type(cond->car) != AO_LISP_CONS) {
-					ao_lisp_error(AO_LISP_INVALID, "malformed cond");
+				ao_lisp_v = ao_lisp_poly_cons(ao_lisp_stack->actuals)->car;
+				if (!ao_lisp_v || ao_lisp_poly_type(ao_lisp_v) != AO_LISP_CONS) {
+					ao_lisp_error(AO_LISP_INVALID, "invalid cond clause");
 					goto bail;
 				}
-				v = ao_lisp_poly_cons(cond->car)->car;
+				ao_lisp_v = ao_lisp_poly_cons(ao_lisp_v)->car;
+				ao_lisp_stack->state = eval_cond_test;
+				stack_validate_tails();
+				ao_lisp_stack_push();
+				stack_validate_tails();
+				ao_lisp_stack->state = eval_sexpr;
 			}
-		}
-
-		/* Build stack frames for each list */
-		while (ao_lisp_poly_type(v) == AO_LISP_CONS) {
-			if (v == AO_LISP_NIL)
-				break;
-
-			/* Push existing bits on the stack */
-			if (cons++)
-				if (!ao_lisp_stack_push())
-					goto bail;
-
-			actuals = ao_lisp_poly_cons(v);
-			formals = NULL;
-			formals_tail = NULL;
-			save_cond = cond;
-			cond = NULL;
-
-			v = actuals->car;
-
-//			DBG("start: stack"); DBG_CONS(stack); DBG("\n");
-//			DBG("start: actuals"); DBG_CONS(actuals); DBG("\n");
-//			DBG("start: formals"); DBG_CONS(formals); DBG("\n");
-		}
-
-			if (ao_lisp_poly_type(v) == AO_LISP_BUILTIN) {
-				struct ao_lisp_builtin *b = ao_lisp_poly_builtin(v);
-				switch (b->args) {
-				case AO_LISP_NLAMBDA:
-					formals = actuals;
-					goto eval;
-
-				case AO_LISP_MACRO:
-					v = ao_lisp_func(b)(ao_lisp_poly_cons(actuals->cdr));
-					DBG("macro "); DBG_POLY(ao_lisp_cons_poly(actuals));
-					DBG(" -> "); DBG_POLY(v);
-					DBG("\n");
-					if (ao_lisp_poly_type(v) != AO_LISP_CONS) {
-						ao_lisp_error(AO_LISP_INVALID, "macro didn't return list");
-						goto bail;
-					}
-					/* Reset frame to the new list */
-					actuals = ao_lisp_poly_cons(v);
-					v = actuals->car;
-					goto restart;
-				}
-		/* Evaluate primitive types */
-
-		DBG ("actual: "); DBG_POLY(v); DBG("\n");
-
-		switch (ao_lisp_poly_type(v)) {
-		case AO_LISP_INT:
-		case AO_LISP_STRING:
 			break;
-		case AO_LISP_ATOM:
-			v = ao_lisp_atom_get(v);
-			break;
-		}
-
-		while (cons) {
-			DBG("add formal: "); DBG_POLY(v); DBG("\n");
-
-			/* We've processed the first element of the list, go check
-			 * what kind of function we've got
-			 */
-			if (formals == NULL) {
-				if (ao_lisp_poly_type(v) == AO_LISP_BUILTIN) {
-					struct ao_lisp_builtin *b = ao_lisp_poly_builtin(v);
-					switch (b->args) {
-					case AO_LISP_NLAMBDA:
-						formals = actuals;
-						goto eval;
-
-					case AO_LISP_MACRO:
-						v = ao_lisp_func(b)(ao_lisp_poly_cons(actuals->cdr));
-						DBG("macro "); DBG_POLY(ao_lisp_cons_poly(actuals));
-						DBG(" -> "); DBG_POLY(v);
-						DBG("\n");
-						if (ao_lisp_poly_type(v) != AO_LISP_CONS) {
-							ao_lisp_error(AO_LISP_INVALID, "macro didn't return list");
-							goto bail;
-						}
-						/* Reset frame to the new list */
-						actuals = ao_lisp_poly_cons(v);
-						v = actuals->car;
-						goto restart;
-					}
+		case eval_cond_test:
+			DBGI("cond_test: "); DBG_POLY(ao_lisp_v); DBG(" actuals "); DBG_POLY(ao_lisp_stack->actuals); DBG("\n");
+			if (ao_lisp_v) {
+				struct ao_lisp_cons *car = ao_lisp_poly_cons(ao_lisp_poly_cons(ao_lisp_stack->actuals)->car);
+				struct ao_lisp_cons *c = ao_lisp_poly_cons(car->cdr);
+				if (c) {
+					ao_lisp_v = c->car;
+					ao_lisp_stack->state = eval_sexpr;
 				} else {
-					switch (func_type(v)) {
-					case _ao_lisp_atom_lambda:
-					case _ao_lisp_atom_lexpr:
-						break;
-					case _ao_lisp_atom_nlambda:
-						formals = actuals;
-						goto eval;
-					case _ao_lisp_atom_macro:
-						break;
-					default:
-						ao_lisp_error(AO_LISP_INVALID, "operator is not a function");
-						goto bail;
-					}
+					ao_lisp_stack->state = eval_val;
 				}
-			}
-
-			formal = ao_lisp_cons_cons(v, NULL);
-			if (formals_tail)
-				formals_tail->cdr = ao_lisp_cons_poly(formal);
-			else
-				formals = formal;
-			formals_tail = formal;
-			actuals = ao_lisp_poly_cons(actuals->cdr);
-
-			DBG("formals: ");
-			DBG_CONS(formals);
-			DBG("\n");
-			DBG("actuals: ");
-			DBG_CONS(actuals);
-			DBG("\n");
-
-			/* Process all of the arguments */
-			if (actuals) {
-				v = actuals->car;
-				break;
-			}
-
-			v = formals->car;
-
-		eval:
-
-			/* Evaluate the resulting list */
-			if (ao_lisp_poly_type(v) == AO_LISP_BUILTIN) {
-				struct ao_lisp_cons *old_cond = cond;
-				struct ao_lisp_builtin *b = ao_lisp_poly_builtin(v);
-
-				v = ao_lisp_func(b) (ao_lisp_poly_cons(formals->cdr));
-
-				DBG ("eval: ");
-				DBG_CONS(formals);
-				DBG(" -> ");
-				DBG_POLY(v);
-				DBG ("\n");
-				if (ao_lisp_exception)
-					goto bail;
-
-				if (cond != old_cond) {
-					DBG("cond changed from "); DBG_CONS(old_cond); DBG(" to "); DBG_CONS(cond); DBG("\n");
-					actuals = NULL;
-					formals = 0;
-					formals_tail = 0;
-					save_cons = cons;
-					cons = 0;
-					goto restart;
-				}
-			} else {
-				v = ao_lisp_lambda(formals);
-				if (ao_lisp_exception)
-					goto bail;
-			}
-
-		cond_done:
-			--cons;
-			if (cons) {
-				ao_lisp_stack_pop();
-//				DBG("stack pop: stack"); DBG_CONS(stack); DBG("\n");
-//				DBG("stack pop: actuals"); DBG_CONS(actuals); DBG("\n");
-//				DBG("stack pop: formals"); DBG_CONS(formals); DBG("\n");
 			} else {
-				actuals = 0;
-				formals = 0;
-				formals_tail = 0;
-				ao_lisp_frame_current = 0;
-			}
-			if (next_frame) {
-				ao_lisp_frame_current = next_frame;
-				DBG("next frame %d\n", OFFSET(next_frame));
-				next_frame = 0;
-				goto restart;
+				ao_lisp_stack->actuals = ao_lisp_poly_cons(ao_lisp_stack->actuals)->cdr;
+				DBGI("actuals now "); DBG_POLY(ao_lisp_stack->actuals); DBG("\n");
+				ao_lisp_stack->state = eval_cond;
 			}
-		}
-		if (cond) {
-			DBG("next cond cons is %d\n", cons);
-			if (v) {
-				v = ao_lisp_poly_cons(cond->car)->cdr;
-				cond = 0;
-				cons = save_cons;
-				if (v != AO_LISP_NIL) {
-					v = ao_lisp_poly_cons(v)->car;
-					DBG("cond complete, sexpr is "); DBG_POLY(v); DBG("\n");
-				}
-				goto cond_done;
-			} else {
-				cond = ao_lisp_poly_cons(cond->cdr);
-				DBG("next cond is "); DBG_CONS(cond); DBG("\n");
-				goto restart;
-			}
-		}
-		if (!cons)
 			break;
+		}
 	}
-	DBG("leaving frame at %d\n", OFFSET(ao_lisp_frame_current));
-	return v;
 bail:
 	ao_lisp_stack_clear();
 	return AO_LISP_NIL;
-#endif
-
+}