altos/lisp: have 'while' return the last body value

Instead of always returning 'nil', let while return the last body
value.

Signed-off-by: Keith Packard <keithp@keithp.com>

2 files changed, 28 insertions, 16 deletions

diff --git a/src/lisp/ao_lisp_error.c b/src/lisp/ao_lisp_error.c
index 7ad7b2b5..937739e9 100644
--- a/src/lisp/ao_lisp_error.c
+++ b/src/lisp/ao_lisp_error.c
@@ -16,23 +16,30 @@
 #include <stdarg.h>
 
 static void
-ao_lisp_error_cons(char *name, struct ao_lisp_cons *cons)
+ao_lisp_error_poly(char *name, ao_poly poly)
 {
 	int first = 1;
 	printf("\t\t%s(", name);
-	if (cons) {
-		while (cons) {
-			if (!first)
-				printf("\t\t         ");
-			else
-				first = 0;
-			ao_lisp_poly_print(cons->car);
-			printf("\n");
-			cons = ao_lisp_poly_cons(cons->cdr);
-		}
-		printf("\t\t         )\n");
-	} else
-		printf(")\n");
+	if (ao_lisp_poly_type(poly) == AO_LISP_CONS) {
+		struct ao_lisp_cons *cons = ao_lisp_poly_cons(poly);
+
+		if (cons) {
+			while (cons) {
+				if (!first)
+					printf("\t\t         ");
+				else
+					first = 0;
+				ao_lisp_poly_print(cons->car);
+				printf("\n");
+				cons = ao_lisp_poly_cons(cons->cdr);
+			}
+			printf("\t\t         )\n");
+		} else
+			printf(")\n");
+	} else {
+		ao_lisp_poly_print(poly);
+		printf("\n");
+	}
 }
 
 static void tabs(int indent)
@@ -87,8 +94,8 @@ ao_lisp_stack_print(void)
 		printf("\t\texpr:   "); ao_lisp_poly_print(s->list); printf("\n");
 		printf("\t\tstate:  %s\n", state_names[s->state]);
 //		printf("\t\tmacro:  %s\n", s->macro ? "true" : "false");
-		ao_lisp_error_cons ("sexprs: ", ao_lisp_poly_cons(s->sexprs));
-		ao_lisp_error_cons ("values: ", ao_lisp_poly_cons(s->values));
+		ao_lisp_error_poly ("sexprs: ", s->sexprs);
+		ao_lisp_error_poly ("values: ", s->values);
 		ao_lisp_error_frame(2, "frame:  ", ao_lisp_poly_frame(s->frame));
 //		ao_lisp_error_frame(2, "mframe: ", ao_lisp_poly_frame(s->macro_frame));
 		printf("\t]\n");
diff --git a/src/lisp/ao_lisp_eval.c b/src/lisp/ao_lisp_eval.c
index 5fa9e0ad..ef521605 100644
--- a/src/lisp/ao_lisp_eval.c
+++ b/src/lisp/ao_lisp_eval.c
@@ -525,6 +525,7 @@ ao_lisp_eval_while(void)
 	DBGI(".. frame "); DBG_POLY(ao_lisp_frame_poly(ao_lisp_frame_current)); DBG("\n");
 	DBGI(".. saved frame "); DBG_POLY(ao_lisp_stack->frame); DBG("\n");
 
+	ao_lisp_stack->values = ao_lisp_v;
 	if (!ao_lisp_stack->sexprs) {
 		ao_lisp_v = AO_LISP_NIL;
 		ao_lisp_stack->state = eval_val;
@@ -548,6 +549,7 @@ ao_lisp_eval_while_test(void)
 	DBGI(".. saved frame "); DBG_POLY(ao_lisp_stack->frame); DBG("\n");
 
 	if (ao_lisp_v) {
+		ao_lisp_stack->values = ao_lisp_v;
 		ao_lisp_v = ao_lisp_poly_cons(ao_lisp_stack->sexprs)->cdr;
 		ao_lisp_stack->state = eval_while;
 		if (!ao_lisp_stack_push())
@@ -556,7 +558,10 @@ ao_lisp_eval_while_test(void)
 		ao_lisp_stack->sexprs = ao_lisp_v;
 	}
 	else
+	{
 		ao_lisp_stack->state = eval_val;
+		ao_lisp_v = ao_lisp_stack->values;
+	}
 	return 1;
 }