Tag all objects as roots during parsing

4 files changed, 109 insertions, 69 deletions

diff --git a/src/bootstrap/main.c b/src/bootstrap/main.c
index 575a924..ce1fdfe 100755
--- a/src/bootstrap/main.c
+++ b/src/bootstrap/main.c
@@ -36,55 +36,61 @@ init(void) {
     obj_true = alloc_object(OBJ_TYPE_BOOL);
     obj_false = alloc_object(OBJ_TYPE_BOOL);
     obj_err = alloc_object(OBJ_TYPE_ERR);
-
-    // Global environment.
-    global_env = env_create(NULL);
-
-    // Primitive symbols.
-    MAKE_ENV_VAR(global_env, "else", obj_true);
-    MAKE_ENV_VAR(global_env, "nil", obj_nil);
-
-    // Primitive procedures.
-    MAKE_ENV_PROC(global_env, "eval", proc_eval);
-    MAKE_ENV_PROC(global_env, "quote", proc_quote);
-    MAKE_ENV_PROC(global_env, "car", proc_car);
-    MAKE_ENV_PROC(global_env, "cdr", proc_cdr);
-    MAKE_ENV_PROC(global_env, "cons", proc_cons);
-    MAKE_ENV_PROC(global_env, "list", proc_list);
-    MAKE_ENV_PROC(global_env, "+", proc_sum);
-    MAKE_ENV_PROC(global_env, "-", proc_sub);
-    MAKE_ENV_PROC(global_env, "*", proc_mul);
-    MAKE_ENV_PROC(global_env, "/", proc_div);
-    MAKE_ENV_PROC(global_env, "%", proc_mod);
-    MAKE_ENV_PROC(global_env, "print", proc_print);
-    MAKE_ENV_PROC(global_env, "display", proc_display);
-    MAKE_ENV_PROC(global_env, "newline", proc_newline);
-    MAKE_ENV_PROC(global_env, "boolean?", proc_is_boolean);
-    MAKE_ENV_PROC(global_env, "nil?", proc_is_nil);
-    MAKE_ENV_PROC(global_env, "symbol?", proc_is_symbol);
-    MAKE_ENV_PROC(global_env, "string?", proc_is_string);
-    MAKE_ENV_PROC(global_env, "fixnum?", proc_is_fixnum);
-    MAKE_ENV_PROC(global_env, "pair?", proc_is_pair);
-    MAKE_ENV_PROC(global_env, "procedure?", proc_is_procedure);
-    MAKE_ENV_PROC(global_env, "error?", proc_is_error);
-    MAKE_ENV_PROC(global_env, "not", proc_not);
-    MAKE_ENV_PROC(global_env, "and", proc_and);
-    MAKE_ENV_PROC(global_env, "or", proc_or);
-    MAKE_ENV_PROC(global_env, "if", proc_if);
-    MAKE_ENV_PROC(global_env, "cond", proc_cond);
-    MAKE_ENV_PROC(global_env, "<", proc_num_less_than);
-    MAKE_ENV_PROC(global_env, "<=", proc_num_lesseq_than);
-    MAKE_ENV_PROC(global_env, ">", proc_num_greater_than);
-    MAKE_ENV_PROC(global_env, ">=", proc_num_greatereq_than);
-    MAKE_ENV_PROC(global_env, "=", proc_num_equal);
-    MAKE_ENV_PROC(global_env, "eq?", proc_equal);
-    MAKE_ENV_PROC(global_env, "def", proc_define);
-    MAKE_ENV_PROC(global_env, "set!", proc_set);
-    MAKE_ENV_PROC(global_env, "lambda", proc_lambda);
-    MAKE_ENV_PROC(global_env, "fun", proc_fun);
-
-    // Runtime procedures.
-    MAKE_ENV_PROC(global_env, "supress-errors", proc_supress_errors);
+    obj_quote = make_symbol((StringView){"quote", 5});
+    push_root(obj_nil);
+    push_root(obj_true);
+    push_root(obj_false);
+    push_root(obj_err);
+    push_root(obj_quote);
+
+//     // Global environment.
+//     global_env = env_create(NULL);
+
+//     // Primitive symbols.
+//     MAKE_ENV_VAR(global_env, "else", obj_true);
+//     MAKE_ENV_VAR(global_env, "nil", obj_nil);
+
+//     // Primitive procedures.
+//     MAKE_ENV_PROC(global_env, "eval", proc_eval);
+//     MAKE_ENV_PROC(global_env, "quote", proc_quote);
+//     MAKE_ENV_PROC(global_env, "car", proc_car);
+//     MAKE_ENV_PROC(global_env, "cdr", proc_cdr);
+//     MAKE_ENV_PROC(global_env, "cons", proc_cons);
+//     MAKE_ENV_PROC(global_env, "list", proc_list);
+//     MAKE_ENV_PROC(global_env, "+", proc_sum);
+//     MAKE_ENV_PROC(global_env, "-", proc_sub);
+//     MAKE_ENV_PROC(global_env, "*", proc_mul);
+//     MAKE_ENV_PROC(global_env, "/", proc_div);
+//     MAKE_ENV_PROC(global_env, "%", proc_mod);
+//     MAKE_ENV_PROC(global_env, "print", proc_print);
+//     MAKE_ENV_PROC(global_env, "display", proc_display);
+//     MAKE_ENV_PROC(global_env, "newline", proc_newline);
+//     MAKE_ENV_PROC(global_env, "boolean?", proc_is_boolean);
+//     MAKE_ENV_PROC(global_env, "nil?", proc_is_nil);
+//     MAKE_ENV_PROC(global_env, "symbol?", proc_is_symbol);
+//     MAKE_ENV_PROC(global_env, "string?", proc_is_string);
+//     MAKE_ENV_PROC(global_env, "fixnum?", proc_is_fixnum);
+//     MAKE_ENV_PROC(global_env, "pair?", proc_is_pair);
+//     MAKE_ENV_PROC(global_env, "procedure?", proc_is_procedure);
+//     MAKE_ENV_PROC(global_env, "error?", proc_is_error);
+//     MAKE_ENV_PROC(global_env, "not", proc_not);
+//     MAKE_ENV_PROC(global_env, "and", proc_and);
+//     MAKE_ENV_PROC(global_env, "or", proc_or);
+//     MAKE_ENV_PROC(global_env, "if", proc_if);
+//     MAKE_ENV_PROC(global_env, "cond", proc_cond);
+//     MAKE_ENV_PROC(global_env, "<", proc_num_less_than);
+//     MAKE_ENV_PROC(global_env, "<=", proc_num_lesseq_than);
+//     MAKE_ENV_PROC(global_env, ">", proc_num_greater_than);
+//     MAKE_ENV_PROC(global_env, ">=", proc_num_greatereq_than);
+//     MAKE_ENV_PROC(global_env, "=", proc_num_equal);
+//     MAKE_ENV_PROC(global_env, "eq?", proc_equal);
+//     MAKE_ENV_PROC(global_env, "def", proc_define);
+//     MAKE_ENV_PROC(global_env, "set!", proc_set);
+//     MAKE_ENV_PROC(global_env, "lambda", proc_lambda);
+//     MAKE_ENV_PROC(global_env, "fun", proc_fun);
+
+//     // Runtime procedures.
+//     MAKE_ENV_PROC(global_env, "supress-errors", proc_supress_errors);
 }
 
 void
@@ -102,17 +108,40 @@ process_source(const StringView *source) {
         .current = 0,
     };
     while (has_next_token(&visitor) && peek_token(&visitor).type != TOKEN_EOF) {
+        // check the stack before parsing
+        size_t root_stack_size = gc.roots.size;
         Object *root = parse_tree(&visitor);
+        gc.roots.size = root_stack_size;
+        push_root(root);
+        // printf("AFTER: %ld\n", gc.roots.size);
+        // return the stack before parsing to previous state except we now have
+        // the root object as well.
+        // printf("-----------\n");
+        // printf("ROOTS: \n");
+        // for (size_t i = 0; i < gc.roots.size; i++) {
+        //     display(gc.roots.buf[i]);
+        //     printf("\n");
+        // }
+        // printf("...........\n");
+        for (size_t i = 0; i < gc.obj_cap; i++) {
+            Object *obj = &gc.obj_list[i];
+            printf("marked? : %d  ", obj->marked);
+            printf("type: %d ", obj->type);
+            display(obj);
+            printf("\n");
+        }
+        // printf("===========\n");
         if (root == obj_err || errors_n != 0) {
             break;
         }
 
-        // FIXME: Not freeing result or intermediate objects, can leak memory.
         Object *result = eval(global_env, root);
         if (result != obj_nil) {
             display(result);
             printf("\n");
         }
+        pop_root();
+        // mark_and_sweep();
     }
 
     if (tokens.buf != NULL) {
diff --git a/src/bootstrap/objects.c b/src/bootstrap/objects.c
index cf881a0..2bd5b1a 100644
--- a/src/bootstrap/objects.c
+++ b/src/bootstrap/objects.c
@@ -14,6 +14,7 @@ struct Environment;
 
 typedef struct Object {
     ObjectType type;
+    bool marked;
     union {
         // OBJ_TYPE_FIXNUM
         ssize_t fixnum;
@@ -56,17 +57,13 @@ static Object *obj_nil;
 static Object *obj_true;
 static Object *obj_false;
 static Object *obj_err;
+static Object *obj_quote;
 
 //
 // Constructors.
 //
 
-Object *
-alloc_object(ObjectType type) {
-    Object *obj = malloc(sizeof(Object));
-    obj->type = type;
-    return obj;
-}
+Object * alloc_object(ObjectType);
 
 Object *
 make_fixnum(ssize_t num) {
@@ -141,14 +138,14 @@ obj_duplicate(Object *obj) {
             append_string(copy, (StringView){obj->string, obj->string_n});
         } break;
         case OBJ_TYPE_PAIR: {
-            // Object *root = make_pair(obj_duplicate(obj->car), obj_nil);
-            // copy = root;
-            // obj = obj->cdr;
-            // while (obj != obj_nil) {
-            //     root->cdr = make_pair(obj_duplicate(obj->car), obj_nil);
-            //     root = root->cdr;
-            //     obj = obj->cdr;
-            // }
+            Object *root = make_pair(obj_duplicate(obj->car), obj_nil);
+            copy = root;
+            obj = obj->cdr;
+            while (obj != obj_nil) {
+                root->cdr = make_pair(obj_duplicate(obj->car), obj_nil);
+                root = root->cdr;
+                obj = obj->cdr;
+            }
         } break;
     }
     return copy;
diff --git a/src/bootstrap/parser.c b/src/bootstrap/parser.c
index 869678e..77ece9d 100644
--- a/src/bootstrap/parser.c
+++ b/src/bootstrap/parser.c
@@ -18,6 +18,8 @@ has_next_token(const Visitor *visitor) {
     return visitor->current < visitor->tokens.size;
 }
 
+void push_root(Object*);
+
 Object *
 parse_fixnum(Token tok) {
     ssize_t num = 0;
@@ -30,7 +32,10 @@ parse_fixnum(Token tok) {
         }
         num = num * 10 + (c - '0');
     }
-    return make_fixnum(num * sign);
+
+    Object *obj = make_fixnum(num * sign);
+    push_root(obj);
+    return obj;
 }
 
 Object * parse_tree(Visitor *vs);
@@ -41,11 +46,13 @@ parse_list(Visitor *vs) {
     if (tok.type == TOKEN_EOF) {
         return obj_err;
     }
+    Object *root = make_pair(obj_nil, obj_nil);
+    push_root(root);
     Object *next_obj = parse_tree(vs);
     if (next_obj == obj_err) {
         return obj_err;
     }
-    Object *root = make_pair(next_obj, obj_nil);
+    root->car = next_obj;
     Object *list = root;
     while (has_next_token(vs)) {
         Token tok = peek_token(vs);
@@ -89,12 +96,15 @@ parse_tree(Visitor *vs) {
             return obj_err;
         } break;
         case TOKEN_QUOTE: {
-            Object *quote_sym = make_symbol((StringView){"quote", 5});
+            Object *base = make_pair(obj_quote, obj_nil);
+            base->cdr = make_pair(obj_nil, obj_nil);
+            push_root(base);
             Object *next_obj = parse_tree(vs);
             if (next_obj == obj_err) {
                 return obj_err;
             }
-            return make_pair(quote_sym, make_pair(next_obj, obj_nil));
+            base->cdr->car = next_obj;
+            return base;
         } break;
         case TOKEN_LPAREN: {
             Object *obj = parse_list(vs);
@@ -110,11 +120,14 @@ parse_tree(Visitor *vs) {
         } break;
         case TOKEN_STRING: {
             Object *obj = make_string();
+            push_root(obj);
             append_string(obj, tok.value);
             return obj;
         } break;
         case TOKEN_SYMBOL: {
-            return make_symbol(tok.value);
+            Object *obj = make_symbol(tok.value);
+            push_root(obj);
+            return obj;
         } break;
         case TOKEN_NIL: {
             return obj_nil;
diff --git a/src/bootstrap/primitives.c b/src/bootstrap/primitives.c
index 4c3e4c6..35208b0 100644
--- a/src/bootstrap/primitives.c
+++ b/src/bootstrap/primitives.c
@@ -2,6 +2,7 @@
 
 Object *
 eval(Environment* env, Object *root) {
+    return obj_nil; // DEBUG: gc
     switch (root->type) {
         case OBJ_TYPE_ERR:
         case OBJ_TYPE_PROCEDURE: