From 06068ab3e07a66d9017b97da28754ceee13d062a Mon Sep 17 00:00:00 2001
From: blueloveTH <blueloveTH@foxmail.com>
Date: Wed, 3 May 2023 21:43:37 +0800
Subject: [PATCH] ...

---
 docs/features/basic.md |  4 +---
 docs/features/goto.md  | 10 ++++------
 python/builtins.py     |  4 +++-
 src/ceval.h            |  2 +-
 src/compiler.h         |  9 ++++-----
 src/lexer.h            | 26 +++++++++++++++++++-------
 src/pocketpy.h         | 20 +++++++++++++++-----
 tests/27_goto.py       |  8 ++++----
 8 files changed, 51 insertions(+), 32 deletions(-)

diff --git a/docs/features/basic.md b/docs/features/basic.md
index 04312fa0..3f8b3fd0 100644
--- a/docs/features/basic.md
+++ b/docs/features/basic.md
@@ -1,11 +1,9 @@
 ---
 icon: dot
-order: 100
 title: Basic Features
+order: 100
 ---
 
-# basic
-
 The following table shows the basic features of pkpy with respect to [cpython](https://github.com/python/cpython).
 The features marked with `YES` are supported, and the features marked with `NO` are not supported.
 
diff --git a/docs/features/goto.md b/docs/features/goto.md
index e694ae43..1bbc8f3d 100644
--- a/docs/features/goto.md
+++ b/docs/features/goto.md
@@ -3,8 +3,6 @@ icon: dot
 title: Goto Statement
 ---
 
-# goto/label
-
 pkpy supports `goto` and `label` just like C. You are allowed to change the control flow unconditionally.
 
 ## Syntax
@@ -12,8 +10,8 @@ pkpy supports `goto` and `label` just like C. You are allowed to change the cont
 Labels are named a dot `.` and an identifier.
 
 ```
-goto .<identifier>
-label .<identifier>
+$goto <identifier>
+$label <identifier>
 ```
 
 ## Example
@@ -22,7 +20,7 @@ label .<identifier>
 for i in range(10):
   for j in range(10):
     for k in range(10):
-      goto .exit
+      $goto exit
 
-label .exit
+$label exit
 ```
diff --git a/python/builtins.py b/python/builtins.py
index ddce6c49..a3275a6d 100644
--- a/python/builtins.py
+++ b/python/builtins.py
@@ -1,6 +1,8 @@
+import sys as _sys
+
 def print(*args, sep=' ', end='\n'):
     s = sep.join([str(i) for i in args])
-    __sys_stdout_write(s + end)
+    _sys.stdout.write(s + end)
 
 def round(x, ndigits=0):
     assert ndigits >= 0
diff --git a/src/ceval.h b/src/ceval.h
index 969a886a..7b1d08e0 100644
--- a/src/ceval.h
+++ b/src/ceval.h
@@ -501,7 +501,7 @@ __NEXT_STEP:;
         TOP()->attr().set(_name, _0);
         DISPATCH();
     /*****************************************/
-    // // TODO: using "goto" inside with block may cause __exit__ not called
+    // TODO: using "goto" inside with block may cause __exit__ not called
     TARGET(WITH_ENTER)
         call_method(POPX(), __enter__);
         DISPATCH();
diff --git a/src/compiler.h b/src/compiler.h
index 8a98486b..6e930394 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -795,17 +795,16 @@ __SUBSCR_END:
                 ctx()->emit(OP_WITH_EXIT, BC_NOARG, prev().line);
             } break;
             /*************************************************/
-            // TODO: refactor goto/label use special $ syntax
-            case TK("label"): {
+            case TK("$label"): {
                 if(mode()!=EXEC_MODE) SyntaxError("'label' is only available in EXEC_MODE");
-                consume(TK(".")); consume(TK("@id"));
+                consume(TK("@id"));
                 bool ok = ctx()->add_label(prev().str());
                 if(!ok) SyntaxError("label " + prev().str().escape() + " already exists");
                 consume_end_stmt();
             } break;
-            case TK("goto"):
+            case TK("$goto"):
                 if(mode()!=EXEC_MODE) SyntaxError("'goto' is only available in EXEC_MODE");
-                consume(TK(".")); consume(TK("@id"));
+                consume(TK("@id"));
                 ctx()->emit(OP_GOTO, StrName(prev().str()).index, prev().line);
                 consume_end_stmt();
                 break;
diff --git a/src/lexer.h b/src/lexer.h
index 270c7c1d..db105087 100644
--- a/src/lexer.h
+++ b/src/lexer.h
@@ -21,10 +21,11 @@ constexpr const char* kTokens[] = {
     /*****************************************/
     ".", ",", ":", ";", "#", "(", ")", "[", "]", "{", "}",
     "**", "=", ">", "<", "...", "->", "?", "@", "==", "!=", ">=", "<=",
+    /** SPEC_BEGIN **/
+    "$goto", "$label",
     /** KW_BEGIN **/
     "class", "import", "as", "def", "lambda", "pass", "del", "from", "with", "yield",
     "None", "in", "is", "and", "or", "not", "True", "False", "global", "try", "except", "finally",
-    "goto", "label",      // extended keywords, not available in cpython
     "while", "for", "if", "elif", "else", "break", "continue", "return", "assert", "raise"
 };
 
@@ -38,13 +39,7 @@ constexpr TokenIndex TK(const char token[]) {
         while(*i && *j && *i == *j) { i++; j++;}
         if(*i == *j) return k;
     }
-#ifdef __GNUC__
-    // for old version of gcc, it is not smart enough to ignore FATAL_ERROR()
-    // so we must do a normal return
     return 255;
-#else
-    FATAL_ERROR();
-#endif
 }
 
 #define TK_STR(t) kTokens[t]
@@ -125,6 +120,13 @@ struct Lexer {
         return true;
     }
 
+    bool match_string(const char* s){
+        int s_len = strlen(s);
+        bool ok = strncmp(curr_char, s, s_len) == 0;
+        if(ok) for(int i=0; i<s_len; i++) eatchar_include_newline();
+        return ok;
+    }
+
     int eat_spaces(){
         int count = 0;
         while (true) {
@@ -381,6 +383,16 @@ struct Lexer {
                 case '[': add_token(TK("[")); return true;
                 case ']': add_token(TK("]")); return true;
                 case '@': add_token(TK("@")); return true;
+                case '$': {
+                    for(int i=TK("$goto"); i<=TK("$label"); i++){
+                        // +1 to skip the '$'
+                        if(match_string(TK_STR(i) + 1)){
+                            add_token((TokenIndex)i);
+                            return true;
+                        }
+                    }
+                    SyntaxError("invalid special token");
+                }
                 case '%': add_token_2('=', TK("%"), TK("%=")); return true;
                 case '&': add_token_2('=', TK("&"), TK("&=")); return true;
                 case '|': add_token_2('=', TK("|"), TK("|=")); return true;
diff --git a/src/pocketpy.h b/src/pocketpy.h
index ccc1934d..c63fd680 100644
--- a/src/pocketpy.h
+++ b/src/pocketpy.h
@@ -72,11 +72,6 @@ inline void init_builtins(VM* _vm) {
 #undef BIND_NUM_ARITH_OPT
 #undef BIND_NUM_LOGICAL_OPT
 
-    _vm->bind_builtin_func<1>("__sys_stdout_write", [](VM* vm, ArgsView args) {
-        (*vm->_stdout) << CAST(Str&, args[0]);
-        return vm->None;
-    });
-
     _vm->bind_builtin_func<2>("super", [](VM* vm, ArgsView args) {
         vm->check_non_tagged_type(args[0], vm->tp_type);
         Type type = OBJ_GET(Type, args[0]);
@@ -768,6 +763,21 @@ inline void add_module_time(VM* vm){
 inline void add_module_sys(VM* vm){
     PyObject* mod = vm->new_module("sys");
     vm->setattr(mod, "version", VAR(PK_VERSION));
+
+    PyObject* stdout = vm->heap.gcnew<DummyInstance>(vm->tp_object, {});
+    PyObject* stderr = vm->heap.gcnew<DummyInstance>(vm->tp_object, {});
+    vm->setattr(mod, "stdout", stdout);
+    vm->setattr(mod, "stderr", stderr);
+
+    vm->bind_func<1>(stdout, "write", [](VM* vm, ArgsView args) {
+        (*vm->_stdout) << CAST(Str&, args[0]).sv();
+        return vm->None;
+    });
+
+    vm->bind_func<1>(stderr, "write", [](VM* vm, ArgsView args) {
+        (*vm->_stderr) << CAST(Str&, args[0]).sv();
+        return vm->None;
+    });
 }
 
 inline void add_module_json(VM* vm){
diff --git a/tests/27_goto.py b/tests/27_goto.py
index bd91d252..e4552755 100644
--- a/tests/27_goto.py
+++ b/tests/27_goto.py
@@ -2,9 +2,9 @@ a = []
 
 for i in range(10):         # [0]
     for j in range(10):     # [0-0]
-        goto .test 
+        $goto test 
         print(2)
-    label .test
+    $label test
     a.append(i)
     for k in range(5):      # [0-1]
         for t in range(7):  # [0-1-0]
@@ -16,7 +16,7 @@ b = False
 
 for i in range(10):         # [1]
     for j in range(10):     # [1-0]
-        goto .out
+        $goto out
         b = True
-label .out
+$label out
 assert not b
\ No newline at end of file