diff --git a/makefile b/makefile
index 21bb601..beeff76 100644
--- a/makefile
+++ b/makefile
@@ -29,5 +29,6 @@ test:nasal
 	./nasal -t test/quick_sort.nas
 	./nasal test/scalar.nas
 	./nasal test/trait.nas
+	./nasal -t test/turingmachine.nas
 	./nasal -t test/ycombinator.nas
 	
\ No newline at end of file
diff --git a/nasal_ast.h b/nasal_ast.h
index 26601d6..ed5530c 100644
--- a/nasal_ast.h
+++ b/nasal_ast.h
@@ -138,7 +138,7 @@ public:
     nasal_ast(const uint32_t l=0,const uint32_t t=ast_null):_line(l),_type(t){}
     nasal_ast(const nasal_ast&);
     nasal_ast(nasal_ast&&);
-    void print(const int);
+    void print(int,bool);
     void clear();
     
     nasal_ast& operator=(const nasal_ast&);
@@ -209,10 +209,11 @@ void nasal_ast::clear()
     _child.clear();
 }
 
-void nasal_ast::print(const int depth)
+void nasal_ast::print(int depth,bool last=false)
 {
-    for(int i=0;i<depth;++i)
-        std::cout<<"|  ";
+    static std::vector<std::string> intentation={};
+    for(auto& i:intentation)
+        std::cout<<i;
     std::cout<<ast_name[_type];
     if(
         _type==ast_str ||
@@ -224,8 +225,16 @@ void nasal_ast::print(const int depth)
     else if(_type==ast_num || _type==ast_file)
         std::cout<<":"<<_num;
     std::cout<<'\n';
-    for(auto& i:_child)
-        i.print(depth+1);
+    if(last && depth)
+        intentation.back()="  ";
+    else if(!last && depth)
+        intentation.back()="│ ";
+    for(uint32_t i=0;i<_child.size();++i)
+    {
+        intentation.push_back(i==_child.size()-1?"└─":"├─");
+        _child[i].print(depth+1,i==_child.size()-1);
+        intentation.pop_back();
+    }
 }
 
 #endif
\ No newline at end of file
diff --git a/nasal_dbg.h b/nasal_dbg.h
index da6abc5..8134126 100644
--- a/nasal_dbg.h
+++ b/nasal_dbg.h
@@ -83,7 +83,7 @@ void nasal_dbg::stepinfo()
     uint32_t begin,end;
     uint32_t line=bytecode[pc].line==0?0:bytecode[pc].line-1;
     src.load(files[bytecode[pc].fidx]);
-    printf("source code:\n");
+    printf("\nsource code:\n");
     begin=(line>>3)==0?0:((line>>3)<<3);
     end=(1+(line>>3))<<3;
     for(uint32_t i=begin;i<end && i<src.size();++i)
diff --git a/nasal_err.h b/nasal_err.h
index 4107433..f7eaa37 100644
--- a/nasal_err.h
+++ b/nasal_err.h
@@ -48,14 +48,14 @@ public:
     void err(const char* stage,const std::string& info)
     {
         ++error;
-        std::cout<<"["<<stage<<"] "<<file<<": "<<info<<'\n';
+        std::cout<<"["<<stage<<"] "<<info<<'\n';
     }
     void err(const char* stage,uint32_t line,uint32_t column,const std::string& info)
     {
         ++error;
         if(!line)
         {
-            err(stage,info);
+            std::cout<<"["<<stage<<"] "<<file<<": "<<info<<'\n';
             return;
         }
         std::cout<<"["<<stage<<"] "<<file<<":"<<line<<":"<<column<<" "<<info<<"\n"<<res[line-1]<<'\n';
@@ -68,7 +68,7 @@ public:
         ++error;
         if(!line)
         {
-            err(stage,info);
+            std::cout<<"["<<stage<<"] "<<file<<": "<<info<<'\n';
             return;
         }
         std::cout<<"["<<stage<<"] "<<file<<":"<<line<<" "<<info<<"\n"<<res[line-1]<<'\n';
diff --git a/test/turingmachine.nas b/test/turingmachine.nas
new file mode 100644
index 0000000..df86bba
--- /dev/null
+++ b/test/turingmachine.nas
@@ -0,0 +1,51 @@
+import("lib.nas");
+
+var table=[
+    ['q0','0','1','R','q1'],
+    ['q1','1','1','R','q1'],
+    ['q1','0','0','S','q2'],
+    ['q2','0','1','R','q3'],
+    ['q3',' ',' ','S','q3']
+];
+var prt=func(state,pointer,paper,act=nil){
+    print(state,':',pointer,':',act!=nil?act:'','\n\t');
+    var s='';
+    foreach(var i;paper)
+        s~=i;
+    s~='\n\t';
+    for(var i=0;i<pointer;i+=1)
+        for(var j=0;j<size(paper[i]);j+=1)
+            s~=' ';
+    print(s,'^\n');
+}
+var run=func(table,node,start,stop){
+    var paper=['0','1','0','1','0','a'];
+    var pointer=0;
+    foreach(var action;table){
+        if(!contains(node,action[0]))
+            node[action[0]]=nil;
+        if(!contains(node,action[4]))
+            node[action[4]]=nil;
+    }
+    print("nodes: ",keys(node),'\n');
+    if(!contains(node,start))
+        die(start~" is not a valid node");
+    if(!contains(node,stop))
+        die(stop~" is not a valid node");
+    var state=start;
+    prt(state,pointer,paper);
+    while(state!=stop){
+        foreach(var action;table)
+            if(action[0]==state and (action[1]==paper[pointer] or action[1]==' ')){
+                paper[pointer]=action[2]==' '?paper[pointer]:action[2];
+                if(action[3]=='L') pointer-=1;
+                elsif(action[3]=='R') pointer+=1;
+                elsif(action[3]!='S') die("invalid action <"~action[3]~'>');
+                state=action[4];
+                break;
+            }
+        prt(state,pointer,paper,action);
+    }
+}
+
+run(table,{},'q0','q3');
\ No newline at end of file