added more error report

7 files changed, 97 insertions, 34 deletions

diff --git a/builtin.cpp b/builtin.cpp
index 806d911..374f3f2 100644
--- a/builtin.cpp
+++ b/builtin.cpp
@@ -46,34 +46,44 @@ SpecialOptIf::SpecialOptIf() : SpecialOptObj() {}
 
 void SpecialOptIf::prepare(Cons *pc) {
     state = 0;  // Prepared
+
     pc = pc->cdr;
+    if (pc == empty_list)
+        throw TokenError("if", SYN_ERR_MISS_OR_EXTRA_EXP);
     pc->skip = false;
-    pc->cdr->skip = true;
-    if (pc->cdr->cdr != empty_list)
-        pc->cdr->cdr->skip = true;
+
+    pc = pc->cdr;
+    if (pc == empty_list)
+        throw TokenError("if", SYN_ERR_MISS_OR_EXTRA_EXP);
+
+    pc->skip = true;
+    if (pc->cdr != empty_list)
+        pc->cdr->skip = true;
 }
 
 void SpecialOptIf::pre_call(ArgList *args, Cons *pc,
         Environment *envt) {
     // static_cast because it's a call invocation
-    pc = static_cast<Cons*>(pc->car); 
+    pc = static_cast<Cons*>(pc->car)->cdr; 
+
     // Condition evaluated and the decision is made
     state = 1;
+
     if (args->cdr->car->is_true())
     {
-        pc = pc->cdr;
         pc->skip = true;
-        pc->cdr->skip = false;
-        if (pc->cdr->cdr != empty_list)
-            pc->cdr->cdr->skip = true; // Eval the former
+        pc = pc->cdr;
+        pc->skip = false;
+        if (pc->cdr != empty_list)
+            pc->cdr->skip = true; // Eval the former
     }
     else
     {
-        pc = pc->cdr;
         pc->skip = true;
+        pc = pc->cdr;
         pc->cdr->skip = true;
-        if (pc->cdr->cdr != empty_list)
-            pc->cdr->cdr->skip = false; //Eval the latter
+        if (pc->cdr != empty_list)
+            pc->cdr->skip = false; //Eval the latter
     }
 }
 
@@ -120,8 +130,15 @@ void SpecialOptLambda::prepare(Cons *pc) {
 
 Cons *SpecialOptLambda::call(ArgList *args, Environment * &envt, 
                             Continuation * &cont, FrameObj ** &top_ptr) {
+
     Cons *ret_addr = static_cast<RetAddr*>(*top_ptr)->addr;
     Cons *pc = static_cast<Cons*>(ret_addr->car);
+
+    if (pc->cdr == empty_list)
+        throw TokenError("lambda", SYN_ERR_EMPTY_PARA_LIST);
+    if (pc->cdr->cdr == empty_list)
+        throw TokenError("lambda", SYN_ERR_MISS_OR_EXTRA_EXP);
+
     SymbolList *para_list = static_cast<SymbolList*>(pc->cdr->car); 
     // Clear the flag to avoid side-effects (e.g. proc calling)
     FILL_MARKS(pc, false);
@@ -144,10 +161,16 @@ string SpecialOptLambda::_debug_repr() { return ext_repr(); }
 SpecialOptDefine::SpecialOptDefine() : SpecialOptObj() {}
 
 void SpecialOptDefine::prepare(Cons *pc) {
+    if (pc->cdr == empty_list)
+        throw TokenError("define", SYN_ERR_MISS_OR_EXTRA_EXP);
+
     if (pc->cdr->car->is_simple_obj())  // Simple value assignment
     {
-        pc->cdr->skip = true;           // Skip the identifier
-        pc->cdr->cdr->skip = false; 
+        pc = pc->cdr;
+        if (pc->cdr == empty_list)
+            throw TokenError("define", SYN_ERR_MISS_OR_EXTRA_EXP);
+        pc->skip = true;           // Skip the identifier
+        pc->cdr->skip = false; 
     }                                   // Procedure definition
     else FILL_MARKS(pc, true);          // Skip all parts
 }
@@ -172,8 +195,9 @@ Cons *SpecialOptDefine::call(ArgList *args, Environment * &envt,
     {
         // static_cast because of is_simple_obj() is false
         Cons *plst = static_cast<Cons*>(pc->cdr->car);
+
         if (plst == empty_list)
-            throw NormalError(SYN_ERR_ID_EXPECTED);
+            throw TokenError("if", SYN_ERR_EMPTY_PARA_LIST);
         if (!plst->car->is_sym_obj())
             throw TokenError(first->ext_repr(), SYN_ERR_NOT_AN_ID);
 
@@ -181,7 +205,12 @@ Cons *SpecialOptDefine::call(ArgList *args, Environment * &envt,
         ArgList *para_list = plst->cdr;
         // Clear the flag to avoid side-effects (e.g. proc calling)
         FILL_MARKS(pc, false);
+
         ASTList *body = pc->cdr->cdr;   // Truncate the expression list
+
+        if (body == empty_list)
+            throw TokenError("define", SYN_ERR_MISS_OR_EXTRA_EXP);
+
         for (Cons *ptr = body; ptr != empty_list; ptr = ptr->cdr)
             ptr->next = NULL;           // Make each expression a orphan
 
@@ -199,9 +228,17 @@ string SpecialOptDefine::_debug_repr() { return ext_repr(); }
 #endif
 
 void SpecialOptSet::prepare(Cons *pc) {
-    // TODO: check number of arguments
-    pc->cdr->skip = true;       // Skip the identifier
-    pc->cdr->cdr->skip = false; 
+    pc = pc->cdr;
+    if (pc == empty_list)
+        throw TokenError("set!", SYN_ERR_MISS_OR_EXTRA_EXP);
+
+    pc->skip = true;       // Skip the identifier
+
+    pc = pc->cdr;
+    if (pc == empty_list)
+        throw TokenError("set!", SYN_ERR_MISS_OR_EXTRA_EXP);
+
+    pc->skip = false; 
 }
 
 Cons *SpecialOptSet::call(ArgList *args, Environment * &envt, 
@@ -216,7 +253,7 @@ Cons *SpecialOptSet::call(ArgList *args, Environment * &envt,
     SymObj *id = static_cast<SymObj*>(first);
 
     bool flag = envt->add_binding(id, args->cdr->car, false);
-    if (!flag) throw TokenError(id->ext_repr(), SYN_ERR_UNBOUND_VAR);
+    if (!flag) throw TokenError(id->ext_repr(), RUN_ERR_UNBOUND_VAR);
     *top_ptr++ = new UnspecObj();
     return ret_addr->next;
 }
diff --git a/consts.cpp b/consts.cpp
index 894482e..c7058b0 100644
--- a/consts.cpp
+++ b/consts.cpp
@@ -3,6 +3,10 @@
 const char *SYN_ERR_MSG[] = {
     "\"%s\" is not an valid identifier",
     "Cannot apply the operation \"%s\"",
-    "An identifier is expected",
-    "Unbound variable: \"%s\""
+    "Unbound variable: \"%s\"",
+    "Missing or extra expression in (%s)",
+    "Empty parameter list in (%s)",
+    "Wrong number of arguments to procedure (%s)",
+    "Illegal empty combination ()",
+    "Unexpected \")\""
 };
diff --git a/consts.h b/consts.h
index a4f4ae3..5e3f43d 100644
--- a/consts.h
+++ b/consts.h
@@ -4,8 +4,12 @@
 enum ErrCode {
     SYN_ERR_NOT_AN_ID,
     SYN_ERR_CAN_NOT_APPLY,
-    SYN_ERR_ID_EXPECTED,
-    SYN_ERR_UNBOUND_VAR
+    RUN_ERR_UNBOUND_VAR,
+    SYN_ERR_MISS_OR_EXTRA_EXP,
+    SYN_ERR_EMPTY_PARA_LIST,
+    RUN_ERR_WRONG_NUM_OF_ARGS,
+    SYN_ERR_EMPTY_COMB,
+    READ_ERR_UNEXPECTED_RIGHT_BRACKET
 };
 
 extern const char *SYN_ERR_MSG[];
diff --git a/eval.cpp b/eval.cpp
index dd4be00..efd1114 100644
--- a/eval.cpp
+++ b/eval.cpp
@@ -43,6 +43,9 @@ void push(Cons * &pc, FrameObj ** &top_ptr, Environment *envt) {
     }
     else                                    // Operational Invocation
     {
+        if (pc->car == empty_list)
+            throw NormalError(SYN_ERR_EMPTY_COMB);
+
         *top_ptr++ = new RetAddr(pc);       // Push the return address
         // static_cast because of is_simple_obj() is false
         pc = static_cast<Cons*>(pc->car);  // Go deeper to enter the call
diff --git a/main.cpp b/main.cpp
index 31d7943..e8fe418 100644
--- a/main.cpp
+++ b/main.cpp
@@ -23,11 +23,12 @@ int main() {
 
     while (1)
     {
-        Cons *tree = ast->absorb(tk);
-        if (!tree) break;
-        //tree_print(tree);
+        printf("Sonsi> ");
         try
         {
+            Cons *tree = ast->absorb(tk);
+            if (!tree) break;
+            //tree_print(tree);
             printf("%s\n", eval->run_expr(tree)->ext_repr().c_str());
         }
         catch (GeneralError &e)
diff --git a/model.cpp b/model.cpp
index d53a9bf..2132d1f 100644
--- a/model.cpp
+++ b/model.cpp
@@ -1,5 +1,7 @@
 #include <cstdio>
 #include "model.h"
+#include "exc.h"
+#include "consts.h"
 
 FrameObj::FrameObj(ClassType _ftype) : ftype(_ftype) {}
 
@@ -94,19 +96,26 @@ ProcObj::ProcObj(ASTList *_body,
                     SymbolList *_para_list) :
     OptObj(), body(_body), envt(_envt), para_list(_para_list) {}
 
-Cons *ProcObj::call(ArgList *args, Environment * &_envt,
+Cons *ProcObj::call(ArgList *args, Environment * &genvt,
                     Continuation * &cont, FrameObj ** &top_ptr) {
     // Create a new continuation
     // static_cast see `call` invocation in eval.cpp
     Cons *ret_addr = static_cast<RetAddr*>(*top_ptr)->addr;
-    Continuation *ncont = new Continuation(_envt, ret_addr, cont, body);
-    cont = ncont;                   // Add to the cont chain
-    _envt = new Environment(envt);   // Create local env and recall the closure
-    // TODO: Compare the arguments to the parameters
+    Continuation *_cont = new Continuation(genvt, ret_addr, cont, body);
+    // Create local env and recall the closure
+    Environment *_envt = new Environment(envt);   
     // static_cast<SymObj*> because the para_list is already checked
-    for (Cons *ptr = args->cdr, *ppar = para_list; 
-            ptr != empty_list; ptr = ptr->cdr, ppar = ppar->cdr)
+    Cons *ptr, *ppar;
+    for (ptr = args->cdr, ppar = para_list; 
+            ptr != empty_list && ppar != empty_list; 
+            ptr = ptr->cdr, ppar = ppar->cdr)
         _envt->add_binding(static_cast<SymObj*>(ppar->car), ptr->car);
+
+    if (ptr != empty_list || ppar != empty_list)
+        throw TokenError("", RUN_ERR_WRONG_NUM_OF_ARGS);
+
+    genvt = _envt;
+    cont = _cont;                   
     *top_ptr++ = new RetAddr(NULL);   // Mark the entrance of a cont
     return body;                    // Move pc to the proc entry point
 }
@@ -159,7 +168,8 @@ EvalObj *Environment::get_obj(EvalObj *obj) {
         bool has_key = ptr->binding.count(name);
         if (has_key) return ptr->binding[name];
     }
-    return NULL;                    // Object not found
+    // Object not found
+    throw TokenError(name, RUN_ERR_UNBOUND_VAR);
 }
 
 Continuation::Continuation(Environment *_envt, Cons *_pc, 
diff --git a/parser.cpp b/parser.cpp
index e1724c3..ecfafab 100644
--- a/parser.cpp
+++ b/parser.cpp
@@ -2,6 +2,8 @@
 #include <cctype>
 #include <sstream>
 #include "parser.h"
+#include "exc.h"
+#include "consts.h"
 #include "builtin.h"
 
 using std::stringstream;
@@ -85,8 +87,10 @@ Cons *ASTGenerator::absorb(Tokenizor *tk) {
         else if (token == ")")
         {
             Cons *lst = empty_list;
-            while (*(--top_ptr))
+            while (top_ptr >= parse_stack && *(--top_ptr))
                 lst = new Cons(*top_ptr, lst); // Collect the list
+            if (top_ptr < parse_stack)
+                throw NormalError(READ_ERR_UNEXPECTED_RIGHT_BRACKET);
             *top_ptr++ = lst;
         }
         else *top_ptr++ = ASTGenerator::to_obj(token);