update docs & fix bug in nasal_builtin.h

README.md

@@ -518,11 +518,11 @@ println(a.get());
 
 ### __native functions__
 
-You could add builtin functions of your own
-(written in C/C++) to help you calculate things more quickly.
-But you should add your own code into the source code of this interpreter and re-compile it.
+This part shows how we add native functions in this nasal interpreter.
+If you are interested in this part, this may help you.
+And...
 
-If you want to add your own functions __without__ changing the source code of the interpreter, see the __`module`__ after this part.
+__CAUTION:__ If you want to add your own functions __without__ changing the source code of the interpreter, see the __`module`__ after this part.
 
 If you really want to change source code, check built-in functions in lib.nas and see the example below.
 
@@ -530,6 +530,8 @@ Definition:
 
 ```C++
 nasal_ref builtin_print(nasal_ref*,nasal_gc&);
+// you could also use a macro to define one.
+nas_native(builtin_print);
 ```
 
 Then complete this function using C++:
@@ -538,12 +540,12 @@ Then complete this function using C++:
 nasal_ref builtin_print(nasal_ref* local,nasal_gc& gc)
 {
     // find value with index begin from 1
-    // because local_scope[0] is reserved for value 'me'
+    // because local[0] is reserved for value 'me'
     nasal_ref vec=local[1];
     // main process
     // also check number of arguments and type here
     // if get an error,use builtin_err
-    for(auto i:vec.vec().elems)
+    for(auto& i:vec.vec().elems)
         switch(i.type)
         {
             case vm_none: std::cout<<"undefined";      break;
@@ -556,7 +558,8 @@ nasal_ref builtin_print(nasal_ref* local,nasal_gc& gc)
             case vm_obj:  std::cout<<"<object>";       break;
         }
     std::cout<<std::flush;
-    // generate return value,use gc::alloc(type) to make a new value
+    // generate return value,
+    // use gc::alloc(type) to make a new value
     // or use reserved reference nil/one/zero
     return nil;
 }
@@ -569,7 +572,7 @@ struct func
 {
     const char* name;
     nasal_ref (*func)(nasal_ref*,nasal_gc&);
-} builtin_func[]=
+} builtin[]=
 {
     {"__builtin_print",builtin_print},
     {nullptr,          nullptr      }
@@ -584,7 +587,7 @@ var print=func(elems...){
 };
 ```
 
-In fact the arguments that `__builtin_print` uses is not necessary.
+In fact the arguments that `__builtin_print` uses are not necessary.
 So writting it like this is also right:
 
 ```javascript
@@ -610,7 +613,9 @@ this may cause mark-sweep in `gc::alloc`.
 The value got before will be collected,but stil in use in this builtin function,
 this is a fatal error.
 
-So use `builtin_alloc` in builtin functions like this:
+So use `gc::builtin_alloc` in builtin functions to allocate a new object.
+
+Or use `gc::alloc` like this to avoid sweeping objects incorrectly:
 
 ```C++
 nasal_ref builtin_keys(nasal_ref* local,nasal_gc& gc)
@@ -620,7 +625,7 @@ nasal_ref builtin_keys(nasal_ref* local,nasal_gc& gc)
         return builtin_err("keys","\"hash\" must be hash");
     // push vector into local scope to avoid being sweeped
     if(gc.top+1>=gc.stack+STACK_MAX_DEPTH-1)
-        builtin_err("keys","expand temporary space error:stackoverflow");
+        return builtin_err("keys","expand temporary space error:stackoverflow");
     (++gc.top)[0]=gc.alloc(vm_vec);
     auto& vec=gc.top[0].vec().elems;
     for(auto& iter:hash.hash().elems)
@@ -767,7 +772,15 @@ please change it to:
 
 `canary=gc.stack+STACK_MAX_DEPTH-1;`
 
-If do not change this line, only the debugger runs abnormally. this bug is fixed in `v9.0`
+If do not change this line, only the debugger runs abnormally. this bug is fixed in `v9.0`.
+
+Another bug is that in `nasal_err.h:class nasal_err`, we should add a constructor for this class:
+
+```C++
+    nasal_err():error(0){}
+```
+
+This bug is fixed in `v9.0`.
 
 ## __Parser__
 

nasal_builtin.h

@@ -6,14 +6,6 @@
 #define environ (*_NSGetEnviron())
 #endif
 
-/*
-    builtin functions must be called inside a function like this:
-    var print=func(elems...){
-        return __builtin_print(elems);
-    }
-    builtin function __builtin_print is wrapped up by print
-*/
-
 // declaration of builtin functions
 // to add new builtin function, declare it here and write the definition below
 #define nas_native(name) nasal_ref name(nasal_ref*,nasal_gc&)
@@ -283,7 +275,7 @@ nasal_ref builtin_split(nasal_ref* local,nasal_gc& gc)
 
     // push it to local scope to avoid being sweeped
     if(gc.top+1>=gc.stack+STACK_MAX_DEPTH-1)
-        builtin_err("split","expand temporary space error:stackoverflow");
+        return builtin_err("split","expand temporary space error:stackoverflow");
     (++gc.top)[0]=gc.alloc(vm_vec);
 
     std::vector<nasal_ref>& vec=gc.top[0].vec().elems;
@@ -575,7 +567,7 @@ nasal_ref builtin_keys(nasal_ref* local,nasal_gc& gc)
         return builtin_err("keys","\"hash\" must be hash");
     // push vector into local scope to avoid being sweeped
     if(gc.top+1>=gc.stack+STACK_MAX_DEPTH-1)
-        builtin_err("keys","expand temporary space error:stackoverflow");
+        return builtin_err("keys","expand temporary space error:stackoverflow");
     (++gc.top)[0]=gc.alloc(vm_vec);
     auto& vec=gc.top[0].vec().elems;
     for(auto& iter:hash.hash().elems)
@@ -1032,7 +1024,7 @@ nasal_ref builtin_environ(nasal_ref* local,nasal_gc& gc)
 {
     char** env=environ;
     if(gc.top+1>=gc.stack+STACK_MAX_DEPTH-1)
-        builtin_err("environ","expand temporary space error:stackoverflow");
+        return builtin_err("environ","expand temporary space error:stackoverflow");
     (++gc.top)[0]=gc.alloc(vm_vec);
     auto& vec=gc.top[0].vec().elems;
     while(*env)

nasal_gc.h

@@ -171,7 +171,7 @@ struct nasal_obj
     void clear()
     {
         if(destructor && ptr)
-            {destructor(ptr);}
+            destructor(ptr);
         ptr=nullptr;
         destructor=nullptr;
     }

nasal_vm.h

@@ -6,7 +6,7 @@ class nasal_vm
 protected:
     /* values of nasal_vm */
     uint32_t                 pc;       // program counter
-    nasal_ref*               localr;    // local scope register
+    nasal_ref*               localr;   // local scope register
     const double*            num_table;// const numbers, ref from nasal_codegen
     const std::string*       str_table;// const symbols, ref from nasal_codegen
     std::vector<uint32_t>    imm;      // immediate number

test/bfs.nas

@@ -14,11 +14,7 @@ for(var i=0;i<10;i+=1)
 
 var prt=func()
 {
-    if(os.platform()=="windows")
-        system("cls");
-    else
-        system("clear");
-    var s="+--------------------+\n";
+    var s="\e[0;0H+--------------------+\n";
     for(var i=0;i<10;i+=1)
     {
         s~="|";
@@ -28,6 +24,7 @@ var prt=func()
     }
     s~='+--------------------+\n';
     print(s);
+    unix.sleep(1/144);
 }
 
 var bfs=func(begin,end)
@@ -49,6 +46,7 @@ var bfs=func(begin,end)
             {
                 map[x][y]=3;
                 prt();
+                print("reached.\n");
                 return;
             }
             if(0<=x and x<10 and 0<=y and y<20 and map[x][y]==0)
@@ -63,4 +61,5 @@ var bfs=func(begin,end)
     return;
 }
 
+print("\ec");
 bfs([0,0],[9,19]);

test/life.nas

@@ -23,22 +23,20 @@ var new_map=func()
 
 var prt=func()
 {
-    var s='';
+    var s='\e[0;0H';
     foreach(var line;map)
     {
         foreach(var elem;line)
             s~=elem~' ';
         s~='\n';
     }
-    if(os.platform()=="windows")
-        system("cls");
-    else
-        system("clear");
     print(s);
+    unix.sleep(1/144);
 }
 
 func()
 {
+    print("\ec");
     rand(time(0));
     map=new_map();
     forindex(var i;map)