...

6 files changed, 71 insertions, 10 deletions

diff --git a/builtin.cpp b/builtin.cpp
index e9669b5..8a94a53 100644
--- a/builtin.cpp
+++ b/builtin.cpp
@@ -47,6 +47,7 @@ Pair *SpecialOptIf::call(Pair *args, Environment * &envt,
         if (ret_info->state == empty_list)
         {
             *top_ptr++ = gc.attach(TO_PAIR(args->cdr)->car);
+            gc.expose(args);
             return ret_addr->next;          // Move to the next instruction
         }
         else 
@@ -62,6 +63,7 @@ Pair *SpecialOptIf::call(Pair *args, Environment * &envt,
                 // Undo pop and invoke again
                 top_ptr += 2;
                 ret_info->state = empty_list;
+                gc.expose(args);
                 return second;
             }
             else if (third != empty_list)
@@ -70,11 +72,13 @@ Pair *SpecialOptIf::call(Pair *args, Environment * &envt,
                 // Undo pop and invoke again
                 top_ptr += 2;
                 ret_info->state = empty_list;
+                gc.expose(args);
                 return third;
             }
             else
             {
                 *top_ptr++ = gc.attach(unspec_obj);
+                gc.expose(args);
                 return ret_addr->next;
             }
         }
@@ -84,6 +88,7 @@ Pair *SpecialOptIf::call(Pair *args, Environment * &envt,
         top_ptr += 2;
         ret_info->state = TO_PAIR(TO_PAIR(ret_addr->car)->cdr);
         ret_info->state->next = NULL;
+        gc.expose(args);
         return ret_info->state;
     }
     throw NormalError(INT_ERR);
@@ -162,6 +167,7 @@ Pair *SpecialOptLambda::call(Pair *args, Environment * &envt,
         ptr->next = NULL;    // Make each expression isolated
 
     *top_ptr++ = gc.attach(new ProcObj(body, envt, params));
+    gc.expose(args);
     return ret_addr->next;  // Move to the next instruction
 }
 
@@ -199,6 +205,7 @@ Pair *SpecialOptDefine::call(Pair *args, Environment * &envt,
             top_ptr += 2;
             ret_info->state = TO_PAIR(TO_PAIR(pc->cdr)->cdr);
             ret_info->state->next = NULL;
+            gc.expose(args);
             return ret_info->state;
         }
         if (!first->is_sym_obj())
@@ -235,6 +242,7 @@ Pair *SpecialOptDefine::call(Pair *args, Environment * &envt,
     }
     envt->add_binding(id, obj);
     *top_ptr++ = unspec_obj;
+    gc.expose(args);
     return ret_addr->next;
 }
 
@@ -268,6 +276,7 @@ Pair *SpecialOptSet::call(Pair *args, Environment * &envt,
         top_ptr += 2;
         ret_info->state = TO_PAIR(TO_PAIR(pc->cdr)->cdr);
         ret_info->state->next = NULL;
+        gc.expose(args);
         return ret_info->state;
     }
 
@@ -279,6 +288,7 @@ Pair *SpecialOptSet::call(Pair *args, Environment * &envt,
     bool flag = envt->add_binding(id, TO_PAIR(args->cdr)->car, false);
     if (!flag) throw TokenError(id->ext_repr(), RUN_ERR_UNBOUND_VAR);
     *top_ptr++ = unspec_obj;
+    gc.expose(args);
     return ret_addr->next;
 }
 
@@ -294,6 +304,7 @@ Pair *SpecialOptQuote::call(Pair *args, Environment * &envt,
     Pair *ret_addr = static_cast<RetAddr*>(*top_ptr)->addr;
     Pair *pc = static_cast<Pair*>(ret_addr->car);
     *top_ptr++ = TO_PAIR(pc->cdr)->car;
+    gc.expose(args);
     return ret_addr->next;
 }
 
@@ -312,6 +323,7 @@ Pair *SpecialOptEval::call(Pair *args, Environment * &envt,
     if (ret_info->state)
     {
         *top_ptr++ = TO_PAIR(args->cdr)->car;
+        gc.expose(args);
         return ret_addr->next;          // Move to the next instruction
     }
     else
@@ -319,6 +331,7 @@ Pair *SpecialOptEval::call(Pair *args, Environment * &envt,
         top_ptr += 2;
         ret_info->state = TO_PAIR(args->cdr);
         ret_info->state->next = NULL;
+        gc.expose(args);
         return ret_info->state;
     }
     throw NormalError(INT_ERR);
@@ -338,6 +351,7 @@ Pair *SpecialOptAnd::call(Pair *args, Environment * &envt,
     if (pc->cdr == empty_list)
     {
         *top_ptr++ = new BoolObj(true);
+        gc.expose(args);
         return ret_addr->next;
     }
     if (!ret_info->state)
@@ -345,6 +359,7 @@ Pair *SpecialOptAnd::call(Pair *args, Environment * &envt,
         top_ptr += 2;
         ret_info->state = TO_PAIR(pc->cdr);
         ret_info->state->next = NULL;
+        gc.expose(args);
         return ret_info->state;
     }
     EvalObj *ret = TO_PAIR(args->cdr)->car;
@@ -353,6 +368,7 @@ Pair *SpecialOptAnd::call(Pair *args, Environment * &envt,
         if (ret_info->state->cdr == empty_list) // the last member
         {
             *top_ptr++ = ret;
+            gc.expose(args);
             return ret_addr->next;
         }
         else
@@ -360,12 +376,14 @@ Pair *SpecialOptAnd::call(Pair *args, Environment * &envt,
             top_ptr += 2;
             ret_info->state = TO_PAIR(ret_info->state->cdr);
             ret_info->state->next = NULL;
+            gc.expose(args);
             return ret_info->state;
         }
     }
     else
     {
         *top_ptr++ = ret;
+        gc.expose(args);
         return ret_addr->next;
     }
     throw NormalError(INT_ERR);
@@ -385,6 +403,7 @@ Pair *SpecialOptOr::call(Pair *args, Environment * &envt,
     if (pc->cdr == empty_list)
     {
         *top_ptr++ = new BoolObj(false);
+        gc.expose(args);
         return ret_addr->next;
     }
     if (!ret_info->state)
@@ -392,6 +411,7 @@ Pair *SpecialOptOr::call(Pair *args, Environment * &envt,
         top_ptr += 2;
         ret_info->state = TO_PAIR(pc->cdr);
         ret_info->state->next = NULL;
+        gc.expose(args);
         return ret_info->state;
     }
     EvalObj *ret = TO_PAIR(args->cdr)->car;
@@ -400,6 +420,7 @@ Pair *SpecialOptOr::call(Pair *args, Environment * &envt,
         if (ret_info->state->cdr == empty_list) // the last member
         {
             *top_ptr++ = ret;
+            gc.expose(args);
             return ret_addr->next;
         }
         else
@@ -407,12 +428,14 @@ Pair *SpecialOptOr::call(Pair *args, Environment * &envt,
             top_ptr += 2;
             ret_info->state = TO_PAIR(ret_info->state->cdr);
             ret_info->state->next = NULL;
+            gc.expose(args);
             return ret_info->state;
         }
     }
     else
     {
         *top_ptr++ = ret;
+        gc.expose(args);
         return ret_addr->next;
     }
     throw NormalError(INT_ERR);
@@ -422,8 +445,9 @@ SpecialOptApply::SpecialOptApply() : SpecialOptObj("apply") {}
 
 void SpecialOptApply::prepare(Pair *pc) {}
 
-Pair *SpecialOptApply::call(Pair *args, Environment * &envt,
+Pair *SpecialOptApply::call(Pair *_args, Environment * &envt,
         Continuation * &cont, FrameObj ** &top_ptr) {
+    Pair *args = _args;
     top_ptr++;          // Recover the return address
     if (args->cdr == empty_list)
         throw TokenError(name, RUN_ERR_WRONG_NUM_OF_ARGS);
@@ -458,6 +482,7 @@ Pair *SpecialOptApply::call(Pair *args, Environment * &envt,
             throw TokenError("a list", RUN_ERR_WRONG_TYPE);
     }
     // force the invocation, so that the desired operator will take over
+    gc.expose(_args);
     return NULL;
 }
 
@@ -469,8 +494,9 @@ void SpecialOptForce::prepare(Pair *pc) {
         throw TokenError(name, RUN_ERR_WRONG_NUM_OF_ARGS);
 }
 
-Pair *SpecialOptForce::call(Pair *args, Environment * &envt,
+Pair *SpecialOptForce::call(Pair *_args, Environment * &envt,
         Continuation * &cont, FrameObj ** &top_ptr) {
+    Pair *args = _args;
     args = TO_PAIR(args->cdr);
     RetAddr *ret_info = static_cast<RetAddr*>(*top_ptr);
     Pair *ret_addr = ret_info->addr;
@@ -479,6 +505,7 @@ Pair *SpecialOptForce::call(Pair *args, Environment * &envt,
         EvalObj *mem = args->car;
         prom->feed_mem(mem);
         *top_ptr++ = mem;
+        gc.expose(_args);
         return ret_addr->next;          // Move to the next instruction
     }
     else
@@ -490,6 +517,7 @@ Pair *SpecialOptForce::call(Pair *args, Environment * &envt,
         if (mem)                        // fetch from memorized result
         {
             *top_ptr++ = mem;
+            gc.expose(_args);
             return ret_addr->next;      
         }
         else                            // force
@@ -497,6 +525,7 @@ Pair *SpecialOptForce::call(Pair *args, Environment * &envt,
             top_ptr += 2;
             ret_info->state = prom->get_entry();
             ret_info->state->next = NULL;
+            gc.expose(_args);
             return ret_info->state;
         }
     }
@@ -516,6 +545,7 @@ Pair *SpecialOptDelay::call(Pair *args, Environment * &envt,
     Pair *ret_addr = static_cast<RetAddr*>(*top_ptr)->addr;
     Pair *pc = static_cast<Pair*>(ret_addr->car);
     *top_ptr++ = new PromObj(TO_PAIR(pc->cdr)->car);
+    gc.expose(args);
     return ret_addr->next;          // Move to the next instruction
 }
 
diff --git a/eval.cpp b/eval.cpp
index 2f5921d..e21ae7b 100644
--- a/eval.cpp
+++ b/eval.cpp
@@ -2,6 +2,7 @@
 #include "builtin.h"
 #include "exc.h"
 #include "consts.h"
+#include "gc.h"
 #include <cstdio>
 
 extern Pair *empty_list;
@@ -109,6 +110,7 @@ inline bool make_exec(Pair *ptr) {
 }
 
 inline void push(Pair * &pc, FrameObj ** &top_ptr, Environment *envt) {
+    gc.attach(pc);
 //    if (pc->car == NULL)
  //       puts("oops");
     if (pc->car->is_simple_obj())           // Not an opt invocation
@@ -180,6 +182,7 @@ EvalObj *Evaluator::run_expr(Pair *prog) {
             }
             else
             {
+                gc.attach(args);
                 EvalObj *opt = args->car;
                 if (opt->is_opt_obj())
                     pc = static_cast<OptObj*>(opt)->
@@ -189,6 +192,7 @@ EvalObj *Evaluator::run_expr(Pair *prog) {
             }
         }
     }
+    gc.expose(prog);
     // static_cast because the previous while condition
     return static_cast<EvalObj*>(*(eval_stack));
 }
diff --git a/main.cpp b/main.cpp
index a193b68..7549daa 100644
--- a/main.cpp
+++ b/main.cpp
@@ -48,8 +48,15 @@ void print_help(const char *cmd) {
     exit(0);
 }
 
+EmptyList *empty_list = new EmptyList();
+UnspecObj *unspec_obj = new UnspecObj();
+
 int main(int argc, char **argv) {
 
+    freopen("in.scm", "r", stdin);
+    gc.attach(empty_list);
+    gc.attach(unspec_obj);
+
     for (int i = 1; i < argc; i++)
     {
         if (*argv[i] == '-')    // parsing options
@@ -96,5 +103,6 @@ int main(int argc, char **argv) {
         {
             fprintf(stderr, "An error occured: %s\n", e.get_msg().c_str());
         }
+        gc.force();
     }
 }
diff --git a/parser.cpp b/parser.cpp
index 333311e..6abc1c0 100644
--- a/parser.cpp
+++ b/parser.cpp
@@ -5,6 +5,7 @@
 #include "exc.h"
 #include "consts.h"
 #include "builtin.h"
+#include "gc.h"
 
 using std::stringstream;
 
diff --git a/types.cpp b/types.cpp
index e3a7542..1548805 100644
--- a/types.cpp
+++ b/types.cpp
@@ -12,16 +12,24 @@
 const double EPS = 1e-16;
 const int PREC = 16;
 
-EmptyList *empty_list = new EmptyList();
-UnspecObj *unspec_obj = new UnspecObj();
+extern EmptyList *empty_list;
+extern UnspecObj *unspec_obj;
 
-Pair::Pair(EvalObj *_car, EvalObj *_cdr) :
-    EvalObj(CLS_PAIR_OBJ), car(_car), cdr(_cdr),
-    next(NULL) {}
+Pair::Pair(EvalObj *_car, EvalObj *_cdr) : EvalObj(CLS_PAIR_OBJ), 
+    car(_car), cdr(_cdr), next(NULL) {
 
-    ReprCons *Pair::get_repr_cons() {
-        return new PairReprCons(this, this);
-    }
+    gc.attach(car);
+    gc.attach(cdr);
+}
+
+Pair::~Pair() {
+    gc.expose(car);
+    gc.expose(cdr);
+}
+
+ReprCons *Pair::get_repr_cons() {
+    return new PairReprCons(this, this);
+}
 
 
 ParseBracket::ParseBracket(unsigned char _btype) :
@@ -49,6 +57,12 @@ ProcObj::ProcObj(Pair *_body, Environment *_envt, EvalObj *_params) :
     gc.attach(envt);
 }
 
+ProcObj::~ProcObj() {
+    gc.expose(body);
+    gc.expose(params);
+    gc.expose(envt);
+}
+
 Pair *ProcObj::call(Pair *args, Environment * &genvt,
         Continuation * &cont, FrameObj ** &top_ptr) {
     // Create a new continuation
@@ -77,6 +91,7 @@ Pair *ProcObj::call(Pair *args, Environment * &genvt,
     genvt = _envt;
     cont = _cont;
     *top_ptr++ = new RetAddr(NULL);   // Mark the entrance of a cont
+    gc.expose(args);
     return body;                    // Move pc to the proc entry point
 }
 
@@ -208,6 +223,7 @@ BuiltinProcObj::BuiltinProcObj(BuiltinProc f, string _name) :
 
         Pair *ret_addr = static_cast<RetAddr*>(*top_ptr)->addr;
         *top_ptr++ = handler(TO_PAIR(args->cdr), name);
+        gc.expose(args);
         return ret_addr->next;          // Move to the next instruction
     }
 
diff --git a/types.h b/types.h
index e6a541c..1519242 100644
--- a/types.h
+++ b/types.h
@@ -51,6 +51,7 @@ class Pair : public EvalObj {/*{{{*/
         Pair* next;                     /**< The next branch in effect */
 
         Pair(EvalObj *car, EvalObj *cdr);  /**< Create a Pair (car . cdr) */
+        ~Pair();
         ReprCons *get_repr_cons();
 };/*}}}*/
 
@@ -163,6 +164,7 @@ class ProcObj: public OptObj {/*{{{*/
 
         /** Conctructs a ProcObj */
         ProcObj(Pair *body, Environment *envt, EvalObj *params);
+        ~ProcObj();
         Pair *call(Pair *args, Environment * &envt,
                     Continuation * &cont, FrameObj ** &top_ptr);
         ReprCons *get_repr_cons();