altos/lisp: Separate out values from atoms

This enables changing values of atoms declared as constants, should
enable lets, and with some work, even lexical scoping.

this required changing the constant computation to run
ao_lisp_collect() before dumping the block of constant data, and that
uncovered some minor memory manager bugs.

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

1 files changed, 39 insertions, 5 deletions

diff --git a/src/lisp/ao_lisp_make_const.c b/src/lisp/ao_lisp_make_const.c
index 8d3e03a9..6b603979 100644
--- a/src/lisp/ao_lisp_make_const.c
+++ b/src/lisp/ao_lisp_make_const.c
@@ -49,19 +49,43 @@ struct builtin_func funcs[] = {
 
 #define N_FUNC (sizeof funcs / sizeof funcs[0])
 
+struct ao_lisp_frame	*globals;
+
+static int
+is_atom(int offset)
+{
+	struct ao_lisp_atom *a;
+
+	for (a = ao_lisp_atoms; a; a = ao_lisp_poly_atom(a->next))
+		if (((uint8_t *) a->name - ao_lisp_const) == offset)
+			return strlen(a->name);
+	return 0;
+}
+
 int
 main(int argc, char **argv)
 {
 	int	f, o;
 	ao_poly	atom, val;
 	struct ao_lisp_atom	*a;
+	int	in_atom;
 
+	printf("/*\n");
+	printf(" * Generated file, do not edit\n");
+	ao_lisp_root_add(&ao_lisp_frame_type, &globals);
+	globals = ao_lisp_frame_new(0, 0);
 	for (f = 0; f < N_FUNC; f++) {
 		struct ao_lisp_builtin	*b = ao_lisp_make_builtin(funcs[f].func, funcs[f].args);
 		struct ao_lisp_atom	*a = ao_lisp_atom_intern(funcs[f].name);
-		a->val = ao_lisp_builtin_poly(b);
+		globals = ao_lisp_frame_add(globals, ao_lisp_atom_poly(a), ao_lisp_builtin_poly(b));
 	}
 
+	/* boolean constants */
+	a = ao_lisp_atom_intern("nil");
+	globals = ao_lisp_frame_add(globals, ao_lisp_atom_poly(a), AO_LISP_NIL);
+	a = ao_lisp_atom_intern("t");
+	globals = ao_lisp_frame_add(globals, ao_lisp_atom_poly(a), ao_lisp_atom_poly(a));
+
 	for (;;) {
 		atom = ao_lisp_read();
 		if (!atom)
@@ -73,13 +97,19 @@ main(int argc, char **argv)
 			fprintf(stderr, "input must be atom val pairs\n");
 			exit(1);
 		}
-		ao_lisp_poly_atom(atom)->val = val;
+		globals = ao_lisp_frame_add(globals, atom, val);
 	}
 
-	printf("/* constant objects, all referenced from atoms */\n\n");
+	/* Reduce to referenced values */
+	ao_lisp_collect();
+	printf(" */\n");
+
+	globals->readonly = 1;
+
 	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));
+	printf("#define ao_builtin_frame 0x%04x\n", ao_lisp_frame_poly(globals));
 
 	for (a = ao_lisp_atoms; a; a = ao_lisp_poly_atom(a->next)) {
 		char	*n = a->name, c;
@@ -101,10 +131,14 @@ main(int argc, char **argv)
 		else
 			printf(" ");
 		c = ao_lisp_const[o];
-		if (' ' < c && c <= '~' && c != '\'')
+		if (!in_atom)
+			in_atom = is_atom(o);
+		if (in_atom) {
 			printf (" '%c',", c);
-		else
+			in_atom--;
+		} else {
 			printf("0x%02x,", c);
+		}
 	}
 	printf("\n};\n");
 	printf("#endif /* AO_LISP_CONST_BITS */\n");