diff --git a/src/byte_defs.h b/src/byte_defs.h
index 3926376..b220978 100755
--- a/src/byte_defs.h
+++ b/src/byte_defs.h
@@ -89,10 +89,10 @@ typedef struct {
 typedef struct {
 
   PACKED union {
-    char str[5];
+    char str[4];
     u32 pos;
   };
-  u8 len;
+  u16 len;
 
 } PACKED ValueStr;
 
diff --git a/src/code_defs.h b/src/code_defs.h
index 46bf3bf..cdb3e73 100755
--- a/src/code_defs.h
+++ b/src/code_defs.h
@@ -27,24 +27,25 @@ enum BuiltinStatements {
   BI_while  = 11,
   BI_fn     = 12,
   BI_import = 13,
-  BI_add    = 14,
-  BI_sub    = 15,
-  BI_mul    = 16,
-  BI_div    = 17,
-  BI_mod    = 18,
-  BI_sml    = 19,
-  BI_sml_eq = 20,
-  BI_eq     = 21,
-  BI_gt_eq  = 22,
-  BI_gt     = 23,
-  BI_not    = 24,
-  BI_and    = 25,
-  BI_or     = 26,
-  BI_is     = 27,
-  BI_cast   = 28,
+  BI_is     = 14,
+  BI_cast   = 15,
+  BI_add    = 16,
+  BI_sub    = 17,
+  BI_mul    = 18,
+  BI_div    = 19,
+  BI_mod    = 20,
+  BI_sml    = 21,
+  BI_sml_eq = 22,
+  BI_eq     = 23,
+  BI_gt_eq  = 24,
+  BI_gt     = 25,
+  BI_not    = 26,
+  BI_and    = 27,
+  BI_or     = 28,
   BI_len    = 29,
   BI_push   = 30,
   BI_pop    = 31,
+  BI_write  = 32,
   BI__end
 };
 
diff --git a/src/exec_common.c b/src/exec_common.c
index d214ae8..8a9a438 100644
--- a/src/exec_common.c
+++ b/src/exec_common.c
@@ -63,7 +63,7 @@ Value add(Value a, Value b){
       a.v4B.vfl += b.v4B.vfl;
       break;
     case T_str:
-      if(a.vstr.len + b.vstr.len > 5){
+      if(a.vstr.len + b.vstr.len > 4){
         runtime_err("not implem");
       }
       else {
@@ -204,13 +204,44 @@ Value pop(Value a, Value b){
 
 }
 
+Value write(Value a){
+  switch(a.tag.type){
+    case T_null:
+      printf("null");
+      break;
+    case T_int:
+      printf("%d",a.v4B.value);
+      break;
+    case T_fix:
+      printf("%f",f2float(a.v4B.value));
+      break;
+    case T_float:
+      printf("%f",a.v4B.vfl);
+      break;
+    case T_str:
+      if(a.vstr.len > 4){
+        runtime_err("Not implem");
+      }
+      else{
+        char *nstr = strndup(a.vstr.str, 4);
+        nstr[a.vstr.len] = '\0';
+        printf("%s",nstr);
+        free(nstr);
+     }
+   case T_fn:
+      break;
+   default:
+      break;
+  }
+}
+
 const Tag tany = {0,T_null};
 const Tag tint = {0,T_int};
 const Tag tfix = {0,T_fix};
 const Tag tfloat = {0,T_float};
 const Tag tstr = {0,T_str};
 const Tag tfn = {0,T_fn};
-const Tag vec = {1,T_null};
+const Tag tvec = {1,T_null};
 
 #define BICAST(x) ((bi_fn_t*)(x))
 
@@ -220,6 +251,18 @@ FnSig builtins[] = {
   {{tany,tany},2,1,{.bi = BICAST(mul)}},
   {{tany,tany},2,1,{.bi = BICAST(divv)}},
   {{tany,tany},2,1,{.bi = BICAST(mod)}},
+  {{tany,tany},2,1,{.bi = BICAST(sml)}},
+  {{tany,tany},2,1,{.bi = BICAST(sml_eq)}},
+  {{tany,tany},2,1,{.bi = BICAST(eq)}},
+  {{tany,tany},2,1,{.bi = BICAST(gt_eq)}},
+  {{tany,tany},2,1,{.bi = BICAST(gt)}},
+  {{tany}     ,1,1,{.bi = BICAST(not)}},
+  {{tany,tany},2,1,{.bi = BICAST(and)}},
+  {{tany,tany},2,1,{.bi = BICAST(or)}},
+  {{tvec}     ,1,1,{.bi = BICAST(len)}},
+  {{tvec,tany},2,1,{.bi = BICAST(push)}},
+  {{tvec,tint},2,1,{.bi = BICAST(pop)}},
+  {{tany}     ,1,1,{.bi = BICAST(write)}}
 };
 
 char *bi_names[] = {
@@ -227,7 +270,19 @@ char *bi_names[] = {
   "-",
   "*",
   "/",
-  "%"
+  "%",
+  "<",
+  "<=",
+  "=",
+  ">=",
+  ">",
+  "!",
+  "and",
+  "or",
+  "len",
+  "push",
+  "pop",
+  "write"
 };
 
 void symbol_map_add_bi(HashMap *map){
diff --git a/src/interpreter.c b/src/interpreter.c
index a596ad4..f57298f 100644
--- a/src/interpreter.c
+++ b/src/interpreter.c
@@ -42,6 +42,36 @@ Value execute(Statement *stat){
       while(evaluate(execute(stat->children[0])))
         execute(stat->children[1]);
       break;
+    case BI_fn:
+    case BI_import:
+      break;
+    // TODO
+    case BI_is:
+      break;
+    // TODO
+    case BI_cast:
+      break;
+    case ST_Call:
+      FnSig *fn = stat->func;
+      Statement **params = ((Statement*)stat->children[0])->children;
+      if(fn->is_builtin){
+        switch(fn->n_param){
+          case 0:
+            returnv = fn->bi();
+            break;
+          case 1:
+            Value (*fn1)(Value) = (void*)fn->bi;
+            returnv = fn1(execute(params[0]));
+            break;
+          case 2:
+            Value (*fn2)(Value,Value) = (void*)fn->bi;
+            returnv = fn2(execute(params[0]),execute(params[1]));
+            break;
+          default:
+            break;
+        }
+      }
+      break;
   }
   return returnv;
 }
diff --git a/src/parse_utils.c b/src/parse_utils.c
index 8f9a2f8..ad33b6c 100644
--- a/src/parse_utils.c
+++ b/src/parse_utils.c
@@ -23,6 +23,7 @@ int make_stack(){
   if(heap_hashmap(&stack->symbol_map, SYMBOL_MAP_S))
     return 1;
   stack->stack_size = 2048;
+  symbol_map_add_bi(&stack->symbol_map);
 
   return 0;
 }
@@ -133,7 +134,7 @@ Statement *make_operation(i32 type, i32 extrainf, char *name, i32 nparam,
     else {
       fnsig = ret->fnsig;
     }
-    if(nparam > fnsig->n_param)
+    if(param->child_n > fnsig->n_param)
       yyerror("Too many parameters to function");
   }
   stat->type = type;
diff --git a/src/parser.l b/src/parser.l
index 05ffa54..994b9aa 100644
--- a/src/parser.l
+++ b/src/parser.l
@@ -19,6 +19,7 @@
 
 "if"                                  return IF;
 "else"                                return ELSE;
+"while"                               return WHILE;
 "fn"                                  return FN;
 "var"                                 return VAR;
 "let"                                 return LET;
@@ -36,7 +37,7 @@
                                         return CST;
                                       }
 
-[()]                                  return *yytext;
+[();]                                  return *yytext;
 
 [ \t\n]+                              ;
 
diff --git a/src/parser.y b/src/parser.y
index d6acd15..b2a84b8 100644
--- a/src/parser.y
+++ b/src/parser.y
@@ -4,6 +4,7 @@
   #include "types.h"
   #include "code_defs.h"
   #include "parser.h"
+  #include "interpreter.h"
 
   int yylex();
 %}
@@ -33,7 +34,7 @@
 %%
 
 program:
-  expr_list '.'                        {set_entry_point($1); exit(0); }
+  expr_list ';'                        {execute($1); exit(0); }
   ;
 
 type: