diff --git a/main.cpp b/main.cpp
index 8b4aa43..1b68716 100644
--- a/main.cpp
+++ b/main.cpp
@@ -14,7 +14,7 @@ void help()
 {
     std::cout
 #ifdef _WIN32
-    <<"use command \'chcp 65001\' if want to use unicode.\n"
+    <<"use command <chcp 65001> if want to use unicode.\n"
 #endif
     <<"nasal <option>\n"
     <<"option:\n"
@@ -48,7 +48,8 @@ void logo()
     <<"   /  \\/ / _` / __|/ _` | |    \n"
     <<"  / /\\  / (_| \\__ \\ (_| | |  \n"
     <<"  \\_\\ \\/ \\__,_|___/\\__,_|_|\n"
-    <<"nasal interpreter ver 9.0\n"
+    <<"nasal ver : "<<__nasver<<"\n"
+    <<"c++ std   : "<<__cplusplus<<"\n"
     <<"thanks to : https://github.com/andyross/nasal\n"
     <<"code repo : https://github.com/ValKmjolnir/Nasal-Interpreter\n"
     <<"code repo : https://gitee.com/valkmjolnir/Nasal-Interpreter\n"
diff --git a/nasal.h b/nasal.h
index 139c395..3a0051d 100644
--- a/nasal.h
+++ b/nasal.h
@@ -1,6 +1,8 @@
 #ifndef __NASAL_H__
 #define __NASAL_H__
 
+#define __nasver "9.0"
+
 #include <stdint.h>
 #include <unistd.h>
 #include <stdlib.h>
diff --git a/nasal_codegen.h b/nasal_codegen.h
index c24b196..9ee3ee4 100644
--- a/nasal_codegen.h
+++ b/nasal_codegen.h
@@ -548,6 +548,11 @@ void nasal_codegen::mcall(const nasal_ast& ast)
         mcall_id(ast);
         return;
     }
+    if(ast.size()==1) // foreach and forindex use call-id ast to get mcall
+    {
+        mcall_id(ast[0]);
+        return;
+    }
     calc_gen(ast[0]);
     for(size_t i=1;i<ast.size()-1;++i)
     {
@@ -774,10 +779,10 @@ void nasal_codegen::for_gen(const nasal_ast& ast)
         case ast_null:break;
         case ast_def:def_gen(ast[0]);break;
         case ast_multi_assign:multi_assign_gen(ast[0]);break;
-        case ast_nil:case ast_num:case ast_str:case ast_func:break;
-        case ast_vec:case ast_hash:
+        case ast_nil:case ast_num:case ast_str:break;
+        case ast_vec:case ast_hash:case ast_func:
         case ast_call:
-        case ast_equal:case ast_addeq:case ast_subeq:
+        case ast_addeq:case ast_subeq:
         case ast_multeq:case ast_diveq:case ast_lnkeq:
         case ast_neg:case ast_not:
         case ast_add:case ast_sub:
@@ -790,6 +795,25 @@ void nasal_codegen::for_gen(const nasal_ast& ast)
             calc_gen(ast[0]);
             gen(op_pop,0,ast[0].line());
             break;
+        case ast_equal:
+            if(ast[0][0].type()==ast_id)
+            {
+                calc_gen(ast[0][1]);
+                mcall_id(ast[0][0]);
+                // only the first mcall_id can use load
+                if(code.back().op==op_mcalll)
+                    code.back().op=op_loadl;
+                else if(code.back().op==op_mupval)
+                    code.back().op=op_loadu;
+                else
+                    code.back().op=op_loadg;
+            }
+            else
+            {
+                calc_gen(ast[0]);
+                gen(op_pop,0,ast[0].line());
+            }
+            break;
     }
     int jmp_place=code.size();
     if(ast[1].type()==ast_null)
@@ -806,10 +830,10 @@ void nasal_codegen::for_gen(const nasal_ast& ast)
         case ast_null:break;
         case ast_def:def_gen(ast[2]);break;
         case ast_multi_assign:multi_assign_gen(ast[2]);break;
-        case ast_nil:case ast_num:case ast_str:case ast_func:break;
-        case ast_vec:case ast_hash:
+        case ast_nil:case ast_num:case ast_str:break;
+        case ast_vec:case ast_hash:case ast_func:
         case ast_call:
-        case ast_equal:case ast_addeq:
+        case ast_addeq:
         case ast_subeq:case ast_multeq:
         case ast_diveq:case ast_lnkeq:
         case ast_neg:case ast_not:
@@ -821,6 +845,25 @@ void nasal_codegen::for_gen(const nasal_ast& ast)
             calc_gen(ast[2]);
             gen(op_pop,0,ast[2].line());
             break;
+        case ast_equal:
+            if(ast[2][0].type()==ast_id)
+            {
+                calc_gen(ast[2][1]);
+                mcall_id(ast[2][0]);
+                // only the first mcall_id can use load
+                if(code.back().op==op_mcalll)
+                    code.back().op=op_loadl;
+                else if(code.back().op==op_mupval)
+                    code.back().op=op_loadu;
+                else
+                    code.back().op=op_loadg;
+            }
+            else
+            {
+                calc_gen(ast[2]);
+                gen(op_pop,0,ast[2].line());
+            }
+            break;
     }
     gen(op_jmp,jmp_place,ast[2].line());
     code[label_exit].num=code.size();
@@ -843,8 +886,17 @@ void nasal_codegen::forindex_gen(const nasal_ast& ast)
     else
     {
         mcall(ast[0]);
-        gen(op_meq,0,ast[0].line());
-        gen(op_pop,0,ast[0].line());
+        if(code.back().op==op_mcallg)
+            code.back().op=op_loadg;
+        else if(code.back().op==op_mcalll)
+            code.back().op=op_loadl;
+        else if(code.back().op==op_mupval)
+            code.back().op=op_loadu;
+        else
+        {
+            gen(op_meq,0,ast[0].line());
+            gen(op_pop,0,ast[0].line());
+        }
     }
     ++in_iterloop.top();
     block_gen(ast[2]);
@@ -871,8 +923,17 @@ void nasal_codegen::foreach_gen(const nasal_ast& ast)
     else
     {
         mcall(ast[0]);
-        gen(op_meq,0,ast[0].line());
-        gen(op_pop,0,ast[0].line());
+        if(code.back().op==op_mcallg)
+            code.back().op=op_loadg;
+        else if(code.back().op==op_mcalll)
+            code.back().op=op_loadl;
+        else if(code.back().op==op_mupval)
+            code.back().op=op_loadu;
+        else
+        {
+            gen(op_meq,0,ast[0].line());
+            gen(op_pop,0,ast[0].line());
+        }
     }
     ++in_iterloop.top();
     block_gen(ast[2]);
@@ -1042,7 +1103,7 @@ void nasal_codegen::block_gen(const nasal_ast& ast)
     for(auto& tmp:ast.child())
         switch(tmp.type())
         {
-            case ast_null:case ast_nil:case ast_num:case ast_str:case ast_func:break;
+            case ast_null:case ast_nil:case ast_num:case ast_str:break;
             case ast_file:fileindex=tmp.num();break; // special node type in main block
             case ast_def:def_gen(tmp);break;
             case ast_multi_assign:multi_assign_gen(tmp);break;
@@ -1081,6 +1142,7 @@ void nasal_codegen::block_gen(const nasal_ast& ast)
             case ast_id:
             case ast_vec:
             case ast_hash:
+            case ast_func:
             case ast_call:
             case ast_addeq:
             case ast_subeq:
diff --git a/nasal_lexer.h b/nasal_lexer.h
index 4bbc503..44b7299 100644
--- a/nasal_lexer.h
+++ b/nasal_lexer.h
@@ -126,9 +126,16 @@ public:
 
 void nasal_lexer::open(const std::string& file)
 {
+    struct stat buffer;
+    if(stat(file.c_str(),&buffer)==0 && !S_ISREG(buffer.st_mode))
+    {
+        nerr.err("lexer","<"+file+"> is not a regular file.");
+        res="";
+        return;
+    }
     std::ifstream fin(file,std::ios::binary);
     if(fin.fail())
-        nerr.err("lexer","cannot open file <"+file+">.");
+        nerr.err("lexer","failed to open <"+file+">.");
     else
         nerr.load(file);
     std::stringstream ss;
diff --git a/nasal_vm.h b/nasal_vm.h
index dfbca83..18a9b15 100644
--- a/nasal_vm.h
+++ b/nasal_vm.h
@@ -512,6 +512,8 @@ inline void nasal_vm::opr_meq()
 {
     mem_addr[0]=(--gc.top)[0]; // pop old mem_addr[0] and replace it
     mem_addr=nullptr;
+    if(imm[pc])
+        --gc.top;
 }
 inline void nasal_vm::opr_eq()
 {