altos/lisp: add set/setq and ' in reader

Along with other small fixes

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

6 files changed, 183 insertions, 43 deletions

diff --git a/src/lisp/ao_lisp.h b/src/lisp/ao_lisp.h
index 4fac861b..d4108662 100644
--- a/src/lisp/ao_lisp.h
+++ b/src/lisp/ao_lisp.h
@@ -27,6 +27,7 @@
 #ifdef AO_LISP_MAKE_CONST
 #define AO_LISP_POOL_CONST	16384
 extern uint8_t ao_lisp_const[AO_LISP_POOL_CONST];
+#define _ao_lisp_atom_quote ao_lisp_atom_poly(ao_lisp_atom_intern("quote"))
 #else
 #include "ao_lisp_const.h"
 #endif
@@ -62,6 +63,11 @@ extern uint8_t		ao_lisp_exception;
 
 typedef uint16_t	ao_poly;
 
+static inline int
+ao_lisp_is_const(ao_poly poly) {
+	return poly & AO_LISP_CONST;
+}
+
 static inline void *
 ao_lisp_ref(ao_poly poly) {
 	if (poly == AO_LISP_NIL)
@@ -128,6 +134,8 @@ enum ao_lisp_builtin_id {
 	builtin_cdr,
 	builtin_cons,
 	builtin_quote,
+	builtin_set,
+	builtin_setq,
 	builtin_print,
 	builtin_plus,
 	builtin_minus,
diff --git a/src/lisp/ao_lisp_builtin.c b/src/lisp/ao_lisp_builtin.c
index e6d55797..63fb69fd 100644
--- a/src/lisp/ao_lisp_builtin.c
+++ b/src/lisp/ao_lisp_builtin.c
@@ -21,20 +21,46 @@ ao_lisp_builtin_print(ao_poly b)
 	printf("[builtin]");
 }
 
+static int check_argc(struct ao_lisp_cons *cons, int min, int max)
+{
+	int	argc = 0;
+
+	while (cons && argc <= max) {
+		argc++;
+		cons = ao_lisp_poly_cons(cons->cdr);
+	}
+	if (argc < min || argc > max) {
+		ao_lisp_exception |= AO_LISP_INVALID;
+		return 0;
+	}
+	return 1;
+}
+
+static int check_argt(struct ao_lisp_cons *cons, int argc, int type, int nil_ok)
+{
+	ao_poly car;
+
+	/* find the desired arg */
+	while (argc--)
+		cons = ao_lisp_poly_cons(cons->cdr);
+	car = cons->car;
+	if ((!car && !nil_ok) ||
+	    ao_lisp_poly_type(car) != type)
+	{
+		ao_lisp_exception |= AO_LISP_INVALID;
+		return 0;
+	}
+	return 1;
+}
+
 enum math_op { math_plus, math_minus, math_times, math_divide, math_mod };
 
 ao_poly
 ao_lisp_car(struct ao_lisp_cons *cons)
 {
-	if (!cons) {
-		ao_lisp_exception |= AO_LISP_INVALID;
-		return AO_LISP_NIL;
-	}
-	if (!cons->car) {
-		ao_lisp_exception |= AO_LISP_INVALID;
+	if (!check_argc(cons, 1, 1))
 		return AO_LISP_NIL;
-	}
-	if (ao_lisp_poly_type(cons->car) != AO_LISP_CONS) {
+	if (!check_argt(cons, 0, AO_LISP_CONS, 0)) {
 		ao_lisp_exception |= AO_LISP_INVALID;
 		return AO_LISP_NIL;
 	}
@@ -92,6 +118,38 @@ ao_lisp_quote(struct ao_lisp_cons *cons)
 }
 
 ao_poly
+ao_lisp_set(struct ao_lisp_cons *cons)
+{
+	ao_poly	atom, val;
+	if (!check_argc(cons, 2, 2))
+		return AO_LISP_NIL;
+	if (!check_argt(cons, 0, AO_LISP_ATOM, 0))
+		return AO_LISP_NIL;
+
+	atom = cons->car;
+	val = ao_lisp_poly_cons(cons->cdr)->car;
+	if (ao_lisp_is_const(atom)) {
+		ao_lisp_exception |= AO_LISP_INVALID;
+		return AO_LISP_NIL;
+	}
+	ao_lisp_poly_atom(atom)->val = val;
+	return val;
+}
+
+ao_poly
+ao_lisp_setq(struct ao_lisp_cons *cons)
+{
+	struct ao_lisp_cons	*expand = 0;
+	if (!check_argc(cons, 2, 2))
+		return AO_LISP_NIL;
+	expand = ao_lisp_cons_cons(_ao_lisp_atom_set,
+				   ao_lisp_cons_cons(ao_lisp_cons_poly(ao_lisp_cons_cons(_ao_lisp_atom_quote,
+								       ao_lisp_cons_cons(cons->car, NULL))),
+						     ao_lisp_poly_cons(cons->cdr)));
+	return ao_lisp_cons_poly(expand);
+}
+
+ao_poly
 ao_lisp_print(struct ao_lisp_cons *cons)
 {
 	ao_poly	val = AO_LISP_NIL;
@@ -196,6 +254,8 @@ ao_lisp_func_t ao_lisp_builtins[] = {
 	[builtin_cdr] = ao_lisp_cdr,
 	[builtin_cons] = ao_lisp_cons,
 	[builtin_quote] = ao_lisp_quote,
+	[builtin_set] = ao_lisp_set,
+	[builtin_setq] = ao_lisp_setq,
 	[builtin_print] = ao_lisp_print,
 	[builtin_plus] = ao_lisp_plus,
 	[builtin_minus] = ao_lisp_minus,
diff --git a/src/lisp/ao_lisp_eval.c b/src/lisp/ao_lisp_eval.c
index b13d4681..2374fdb2 100644
--- a/src/lisp/ao_lisp_eval.c
+++ b/src/lisp/ao_lisp_eval.c
@@ -111,6 +111,9 @@ ao_lisp_eval(ao_poly v)
 
 					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_exception |= AO_LISP_INVALID;
 							return AO_LISP_NIL;
@@ -160,8 +163,9 @@ ao_lisp_eval(ao_poly v)
 				DBG ("\n");
 			} else {
 				ao_lisp_exception |= AO_LISP_INVALID;
-				return AO_LISP_NIL;
 			}
+			if (ao_lisp_exception)
+				return AO_LISP_NIL;
 		done_eval:
 			if (--cons) {
 				struct ao_lisp_cons	*frame;
@@ -170,10 +174,13 @@ ao_lisp_eval(ao_poly v)
 				frame = ao_lisp_poly_cons(stack->car);
 				actuals = ao_lisp_poly_cons(frame->car);
 				formals = ao_lisp_poly_cons(frame->cdr);
+				formals_tail = NULL;
 
 				/* Recompute the tail of the formals list */
-				for (formal = formals; formal->cdr != AO_LISP_NIL; formal = ao_lisp_poly_cons(formal->cdr));
-				formals_tail = formal;
+				if (formals) {
+					for (formal = formals; formal->cdr != AO_LISP_NIL; formal = ao_lisp_poly_cons(formal->cdr));
+					formals_tail = formal;
+				}
 
 				stack = ao_lisp_poly_cons(stack->cdr);
 				DBG("stack pop: stack"); DBG_CONS(stack); DBG("\n");
diff --git a/src/lisp/ao_lisp_make_const.c b/src/lisp/ao_lisp_make_const.c
index 21e000bf..8d3e03a9 100644
--- a/src/lisp/ao_lisp_make_const.c
+++ b/src/lisp/ao_lisp_make_const.c
@@ -14,6 +14,7 @@
 
 #include "ao_lisp.h"
 #include <stdlib.h>
+#include <ctype.h>
 
 static struct ao_lisp_builtin *
 ao_lisp_make_builtin(enum ao_lisp_builtin_id func, int args) {
@@ -36,6 +37,8 @@ struct builtin_func funcs[] = {
 	"cdr",		AO_LISP_LEXPR,	builtin_cdr,
 	"cons",		AO_LISP_LEXPR,	builtin_cons,
 	"quote",	AO_LISP_NLAMBDA,builtin_quote,
+	"set",		AO_LISP_LEXPR,	builtin_set,
+	"setq",		AO_LISP_MACRO,	builtin_setq,
 	"print",	AO_LISP_LEXPR,	builtin_print,
 	"+",		AO_LISP_LEXPR,	builtin_plus,
 	"-",		AO_LISP_LEXPR,	builtin_minus,
@@ -51,6 +54,7 @@ main(int argc, char **argv)
 {
 	int	f, o;
 	ao_poly	atom, val;
+	struct ao_lisp_atom	*a;
 
 	for (f = 0; f < N_FUNC; f++) {
 		struct ao_lisp_builtin	*b = ao_lisp_make_builtin(funcs[f].func, funcs[f].args);
@@ -76,14 +80,31 @@ main(int argc, char **argv)
 	printf("#define AO_LISP_POOL_CONST %d\n", ao_lisp_top);
 	printf("extern const uint8_t ao_lisp_const[AO_LISP_POOL_CONST] __attribute__((aligned(4)));\n");
 	printf("#define ao_builtin_atoms 0x%04x\n", ao_lisp_atom_poly(ao_lisp_atoms));
+
+	for (a = ao_lisp_atoms; a; a = ao_lisp_poly_atom(a->next)) {
+		char	*n = a->name, c;
+		printf ("#define _ao_lisp_atom_");
+		while ((c = *n++)) {
+			if (isalnum(c))
+				printf("%c", c);
+			else
+				printf("%02x", c);
+		}
+		printf("  0x%04x\n", ao_lisp_atom_poly(a));
+	}
 	printf("#ifdef AO_LISP_CONST_BITS\n");
 	printf("const uint8_t ao_lisp_const[] = {");
 	for (o = 0; o < ao_lisp_top; o++) {
+		uint8_t	c;
 		if ((o & 0xf) == 0)
 			printf("\n\t");
 		else
 			printf(" ");
-		printf("0x%02x,", ao_lisp_const[o]);
+		c = ao_lisp_const[o];
+		if (' ' < c && c <= '~' && c != '\'')
+			printf (" '%c',", c);
+		else
+			printf("0x%02x,", c);
 	}
 	printf("\n};\n");
 	printf("#endif /* AO_LISP_CONST_BITS */\n");
diff --git a/src/lisp/ao_lisp_read.c b/src/lisp/ao_lisp_read.c
index ea98b976..8fc134e5 100644
--- a/src/lisp/ao_lisp_read.c
+++ b/src/lisp/ao_lisp_read.c
@@ -375,12 +375,45 @@ static struct ao_lisp_cons	*read_cons;
 static struct ao_lisp_cons	*read_cons_tail;
 static struct ao_lisp_cons	*read_stack;
 
-static ao_poly
-read_item(void)
+static int
+push_read_stack(int cons, int in_quote)
+{
+	if (cons) {
+		read_stack = ao_lisp_cons_cons(ao_lisp_cons_poly(read_cons),
+					       ao_lisp_cons_cons(ao_lisp_int_poly(in_quote),
+								 read_stack));
+		if (!read_stack)
+			return 0;
+	}
+	read_cons = NULL;
+	read_cons_tail = NULL;
+	return 1;
+}
+
+static int
+pop_read_stack(int cons)
+{
+	int	in_quote = 0;
+	if (cons) {
+		read_cons = ao_lisp_poly_cons(read_stack->car);
+		read_stack = ao_lisp_poly_cons(read_stack->cdr);
+		in_quote = ao_lisp_poly_int(read_stack->car);
+		read_stack = ao_lisp_poly_cons(read_stack->cdr);
+		for (read_cons_tail = read_cons;
+		     read_cons_tail && read_cons_tail->cdr;
+		     read_cons_tail = ao_lisp_poly_cons(read_cons_tail->cdr))
+			;
+	}
+	return in_quote;
+}
+
+ao_poly
+ao_lisp_read(void)
 {
 	struct ao_lisp_atom	*atom;
 	char			*string;
 	int			cons;
+	int			in_quote;
 	ao_poly			v;
 
 	if (!been_here) {
@@ -388,15 +421,17 @@ read_item(void)
 		ao_lisp_root_add(&ao_lisp_cons_type, &read_cons_tail);
 		ao_lisp_root_add(&ao_lisp_cons_type, &read_stack);
 	}
+	parse_token = lex();
 
 	cons = 0;
+	in_quote = 0;
 	read_cons = read_cons_tail = read_stack = 0;
 	for (;;) {
 		while (parse_token == OPEN) {
-			if (cons++)
-				read_stack = ao_lisp_cons_cons(ao_lisp_cons_poly(read_cons), read_stack);
-			read_cons = NULL;
-			read_cons_tail = NULL;
+			if (!push_read_stack(cons, in_quote))
+				return AO_LISP_NIL;
+			cons++;
+			in_quote = 0;
 			parse_token = lex();
 		}
 
@@ -422,40 +457,48 @@ read_item(void)
 			else
 				v = AO_LISP_NIL;
 			break;
+		case QUOTE:
+			if (!push_read_stack(cons, in_quote))
+				return AO_LISP_NIL;
+			cons++;
+			in_quote = 1;
+			v = _ao_lisp_atom_quote;
+			break;
 		case CLOSE:
-			if (cons)
-				v = ao_lisp_cons_poly(read_cons);
-			else
+			if (!cons) {
 				v = AO_LISP_NIL;
-			if (--cons) {
-				read_cons = ao_lisp_poly_cons(read_stack->car);
-				read_stack = ao_lisp_poly_cons(read_stack->cdr);
-				for (read_cons_tail = read_cons;
-				     read_cons_tail && read_cons_tail->cdr;
-				     read_cons_tail = ao_lisp_poly_cons(read_cons_tail->cdr))
-					;
+				break;
 			}
+			v = ao_lisp_cons_poly(read_cons);
+			--cons;
+			in_quote = pop_read_stack(cons);
 			break;
 		}
 
-		if (!cons)
-			break;
+		/* loop over QUOTE ends */
+		for (;;) {
+			if (!cons)
+				return v;
+
+			struct ao_lisp_cons	*read = ao_lisp_cons_cons(v, NULL);
+			if (!read)
+				return AO_LISP_NIL;
+
+			if (read_cons_tail)
+				read_cons_tail->cdr = ao_lisp_cons_poly(read);
+			else
+				read_cons = read;
+			read_cons_tail = read;
+
+			if (!in_quote || !read_cons->cdr)
+				break;
 
-		struct ao_lisp_cons	*read = ao_lisp_cons_cons(v, NULL);
-		if (read_cons_tail)
-			read_cons_tail->cdr = ao_lisp_cons_poly(read);
-		else
-			read_cons = read;
-		read_cons_tail = read;
+			v = ao_lisp_cons_poly(read_cons);
+			--cons;
+			in_quote = pop_read_stack(cons);
+		}
 
 		parse_token = lex();
 	}
 	return v;
 }
-
-ao_poly
-ao_lisp_read(void)
-{
-	parse_token = lex();
-	return read_item();
-}
diff --git a/src/lisp/ao_lisp_rep.c b/src/lisp/ao_lisp_rep.c
index d26d270c..a1f9fa1f 100644
--- a/src/lisp/ao_lisp_rep.c
+++ b/src/lisp/ao_lisp_rep.c
@@ -22,6 +22,7 @@ ao_lisp_read_eval_print(void)
 		in = ao_lisp_read();
 		if (!in)
 			break;
+//		printf ("in: "); ao_lisp_poly_print(in); printf("\n");
 		out = ao_lisp_eval(in);
 		if (ao_lisp_exception) {
 			if (ao_lisp_exception & AO_LISP_OOM)