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

[fw/altos] / src / lisp / ao_lisp_read.c

diff --git a/src/lisp/ao_lisp_read.c b/src/lisp/ao_lisp_read.c
index ea98b9767cb59882ca13e34ffeb343b623995c46..8fc134e59c520629d63267b130da9bef3a9db95b 100644 (file)
--- 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();
-}