Patch #2477: Added from __future__ import unicode_literals

The new PyParser_*Ex() functions are based on Neal's suggestion and initial patch. The new __future__ feature makes all '' and r'' unicode strings. b'' and br'' stay (byte) strings.

Include/code.h

@@ -49,6 +49,7 @@ typedef struct {
 #define CO_FUTURE_ABSOLUTE_IMPORT 0x4000 /* do absolute imports by default */
 #define CO_FUTURE_WITH_STATEMENT  0x8000
 #define CO_FUTURE_PRINT_FUNCTION  0x10000
+#define CO_FUTURE_UNICODE_LITERALS 0x20000
 
 /* This should be defined if a future statement modifies the syntax.
    For example, when a keyword is added.

Include/compile.h

@@ -25,6 +25,7 @@ typedef struct {
 #define FUTURE_ABSOLUTE_IMPORT "absolute_import"
 #define FUTURE_WITH_STATEMENT "with_statement"
 #define FUTURE_PRINT_FUNCTION "print_function"
+#define FUTURE_UNICODE_LITERALS "unicode_literals"
 
 
 struct _mod; /* Declare the existence of this type */

Include/parsetok.h

@@ -28,6 +28,7 @@ typedef struct {
 #endif
 
 #define PyPARSE_PRINT_IS_FUNCTION       0x0004
+#define PyPARSE_UNICODE_LITERALS        0x0008
 
 
 
@@ -41,11 +42,18 @@ PyAPI_FUNC(node *) PyParser_ParseStringFlags(const char *, grammar *, int,
 PyAPI_FUNC(node *) PyParser_ParseFileFlags(FILE *, const char *, grammar *,
 						 int, char *, char *,
 						 perrdetail *, int);
+PyAPI_FUNC(node *) PyParser_ParseFileFlagsEx(FILE *, const char *, grammar *,
+						 int, char *, char *,
+						 perrdetail *, int *);
 
 PyAPI_FUNC(node *) PyParser_ParseStringFlagsFilename(const char *,
 					      const char *,
 					      grammar *, int,
                                               perrdetail *, int);
+PyAPI_FUNC(node *) PyParser_ParseStringFlagsFilenameEx(const char *,
+					      const char *,
+					      grammar *, int,
+                                              perrdetail *, int *);
 
 /* Note that he following function is defined in pythonrun.c not parsetok.c. */
 PyAPI_FUNC(void) PyParser_SetError(perrdetail *);

Include/pythonrun.h

@@ -8,7 +8,8 @@ extern "C" {
 #endif
 
 #define PyCF_MASK (CO_FUTURE_DIVISION | CO_FUTURE_ABSOLUTE_IMPORT | \
-                   CO_FUTURE_WITH_STATEMENT|CO_FUTURE_PRINT_FUNCTION)
+                   CO_FUTURE_WITH_STATEMENT | CO_FUTURE_PRINT_FUNCTION | \
+                   CO_FUTURE_UNICODE_LITERALS)
 #define PyCF_MASK_OBSOLETE (CO_NESTED)
 #define PyCF_SOURCE_IS_UTF8  0x0100
 #define PyCF_DONT_IMPLY_DEDENT 0x0200

Lib/__future__.py

@@ -54,6 +54,7 @@ all_feature_names = [
     "absolute_import",
     "with_statement",
     "print_function",
+    "unicode_literals",
 ]
 
 __all__ = ["all_feature_names"] + all_feature_names
@@ -68,6 +69,7 @@ CO_FUTURE_DIVISION   = 0x2000   # division
 CO_FUTURE_ABSOLUTE_IMPORT = 0x4000 # perform absolute imports by default
 CO_FUTURE_WITH_STATEMENT  = 0x8000   # with statement
 CO_FUTURE_PRINT_FUNCTION  = 0x10000   # print function
+CO_FUTURE_UNICODE_LITERALS = 0x20000 # unicode string literals
 
 class _Feature:
     def __init__(self, optionalRelease, mandatoryRelease, compiler_flag):
@@ -120,3 +122,7 @@ with_statement = _Feature((2, 5, 0, "alpha", 1),
 print_function = _Feature((2, 6, 0, "alpha", 2),
                           (3, 0, 0, "alpha", 0),
                           CO_FUTURE_PRINT_FUNCTION)
+
+unicode_literals = _Feature((2, 6, 0, "alpha", 2),
+                            (3, 0, 0, "alpha", 0),
+                            CO_FUTURE_UNICODE_LITERALS)

Misc/NEWS

@@ -12,6 +12,8 @@ What's New in Python 2.6 alpha 2?
 Core and builtins
 -----------------
 
+- Patch #2477: Added from __future__ import unicode_literals
+
 - Added backport of bytearray type.
 
 - Issue #2355: add Py3k warning for buffer().
@@ -186,6 +188,12 @@ Build
 
 - Patch #2284: Add -x64 option to rt.bat.
 
+C API
+-----
+
+- Patch #2477: Added PyParser_ParseFileFlagsEx() and 
+  PyParser_ParseStringFlagsFilenameEx()
+
 What's New in Python 2.6 alpha 1?
 =================================
 

Parser/parser.c

@@ -202,14 +202,18 @@ future_hack(parser_state *ps)
 	
 	for (i = 0; i < NCH(ch); i += 2) {
 		cch = CHILD(ch, i);
-		if (NCH(cch) >= 1 && TYPE(CHILD(cch, 0)) == NAME &&
-		    strcmp(STR(CHILD(cch, 0)), "with_statement") == 0) {
-			ps->p_flags |= CO_FUTURE_WITH_STATEMENT;
-			break;
-		} else if (NCH(cch) >= 1 && TYPE(CHILD(cch, 0)) == NAME &&
-		    strcmp(STR(CHILD(cch, 0)), "print_function") == 0) {
-			ps->p_flags |= CO_FUTURE_PRINT_FUNCTION;
-			break;
+		if (NCH(cch) >= 1 && TYPE(CHILD(cch, 0)) == NAME) {
+			char *str_ch = STR(CHILD(cch, 0));
+			if (strcmp(str_ch, FUTURE_WITH_STATEMENT) == 0) {
+				ps->p_flags |= CO_FUTURE_WITH_STATEMENT;
+				break;
+			} else if (strcmp(str_ch, FUTURE_PRINT_FUNCTION) == 0) {
+				ps->p_flags |= CO_FUTURE_PRINT_FUNCTION;
+				break;
+			} else if (strcmp(str_ch, FUTURE_UNICODE_LITERALS) == 0) {
+				ps->p_flags |= CO_FUTURE_UNICODE_LITERALS;
+				break;
+			}
 		}
 	}
 }

Parser/parsetok.c

@@ -14,7 +14,7 @@ int Py_TabcheckFlag;
 
 
 /* Forward */
-static node *parsetok(struct tok_state *, grammar *, int, perrdetail *, int);
+static node *parsetok(struct tok_state *, grammar *, int, perrdetail *, int *);
 static void initerr(perrdetail *err_ret, const char* filename);
 
 /* Parse input coming from a string.  Return error code, print some errors. */
@@ -36,6 +36,16 @@ node *
 PyParser_ParseStringFlagsFilename(const char *s, const char *filename,
 			  grammar *g, int start,
 		          perrdetail *err_ret, int flags)
+{
+	int iflags = flags;
+	return PyParser_ParseStringFlagsFilenameEx(s, filename, g, start,
+						   err_ret, &iflags);
+}
+
+node *
+PyParser_ParseStringFlagsFilenameEx(const char *s, const char *filename,
+			  grammar *g, int start,
+		          perrdetail *err_ret, int *flags)
 {
 	struct tok_state *tok;
 
@@ -69,6 +79,14 @@ PyParser_ParseFile(FILE *fp, const char *filename, grammar *g, int start,
 node *
 PyParser_ParseFileFlags(FILE *fp, const char *filename, grammar *g, int start,
 			char *ps1, char *ps2, perrdetail *err_ret, int flags)
+{
+	int iflags = flags;
+	return PyParser_ParseFileFlagsEx(fp, filename, g, start, ps1, ps2, err_ret, &iflags);
+}
+
+node *
+PyParser_ParseFileFlagsEx(FILE *fp, const char *filename, grammar *g, int start,
+			  char *ps1, char *ps2, perrdetail *err_ret, int *flags)
 {
 	struct tok_state *tok;
 
@@ -85,7 +103,6 @@ PyParser_ParseFileFlags(FILE *fp, const char *filename, grammar *g, int start,
 			tok->alterror++;
 	}
 
-
 	return parsetok(tok, g, start, err_ret, flags);
 }
 
@@ -110,7 +127,7 @@ warn(const char *msg, const char *filename, int lineno)
 
 static node *
 parsetok(struct tok_state *tok, grammar *g, int start, perrdetail *err_ret,
-	 int flags)
+	 int *flags)
 {
 	parser_state *ps;
 	node *n;
@@ -123,8 +140,13 @@ parsetok(struct tok_state *tok, grammar *g, int start, perrdetail *err_ret,
 		return NULL;
 	}
 #ifdef PY_PARSER_REQUIRES_FUTURE_KEYWORD
-	if (flags & PyPARSE_PRINT_IS_FUNCTION)
+	if (*flags & PyPARSE_PRINT_IS_FUNCTION) {
 		ps->p_flags |= CO_FUTURE_PRINT_FUNCTION;
+	}
+	if (*flags & PyPARSE_UNICODE_LITERALS) {
+		ps->p_flags |= CO_FUTURE_UNICODE_LITERALS;
+	}
+
 #endif
 
 	for (;;) {
@@ -147,7 +169,7 @@ parsetok(struct tok_state *tok, grammar *g, int start, perrdetail *err_ret,
 			   except if a certain flag is given --
 			   codeop.py uses this. */
 			if (tok->indent &&
-			    !(flags & PyPARSE_DONT_IMPLY_DEDENT))
+			    !(*flags & PyPARSE_DONT_IMPLY_DEDENT))
 			{
 				tok->pendin = -tok->indent;
 				tok->indent = 0;
@@ -191,6 +213,7 @@ parsetok(struct tok_state *tok, grammar *g, int start, perrdetail *err_ret,
 	else
 		n = NULL;
 
+	*flags = ps->p_flags;
 	PyParser_Delete(ps);
 
 	if (n == NULL) {

Python/ast.c

@@ -18,6 +18,7 @@
 /* Data structure used internally */
 struct compiling {
     char *c_encoding; /* source encoding */
+    int c_future_unicode; /* __future__ unicode literals flag */
     PyArena *c_arena; /* arena for allocating memeory */
     const char *c_filename; /* filename */
 };
@@ -36,7 +37,7 @@ static expr_ty ast_for_testlist_gexp(struct compiling *, const node *);
 static expr_ty ast_for_call(struct compiling *, const node *, expr_ty);
 
 static PyObject *parsenumber(const char *);
-static PyObject *parsestr(const char *s, const char *encoding);
+static PyObject *parsestr(struct compiling *, const char *);
 static PyObject *parsestrplus(struct compiling *, const node *n);
 
 #ifndef LINENO
@@ -198,6 +199,7 @@ PyAST_FromNode(const node *n, PyCompilerFlags *flags, const char *filename,
     } else {
         c.c_encoding = NULL;
     }
+    c.c_future_unicode = flags && flags->cf_flags & CO_FUTURE_UNICODE_LITERALS;
     c.c_arena = arena;
     c.c_filename = filename;
 
@@ -3247,13 +3249,13 @@ decode_unicode(const char *s, size_t len, int rawmode, const char *encoding)
  * parsestr parses it, and returns the decoded Python string object.
  */
 static PyObject *
-parsestr(const char *s, const char *encoding)
+parsestr(struct compiling *c, const char *s)
 {
         size_t len;
         int quote = Py_CHARMASK(*s);
         int rawmode = 0;
         int need_encoding;
-        int unicode = 0;
+        int unicode = c->c_future_unicode;
 
         if (isalpha(quote) || quote == '_') {
                 if (quote == 'u' || quote == 'U') {
@@ -3262,6 +3264,7 @@ parsestr(const char *s, const char *encoding)
                 }
                 if (quote == 'b' || quote == 'B') {
                         quote = *++s;
+                        unicode = 0;
                 }
                 if (quote == 'r' || quote == 'R') {
                         quote = *++s;
@@ -3293,12 +3296,12 @@ parsestr(const char *s, const char *encoding)
         }
 #ifdef Py_USING_UNICODE
         if (unicode || Py_UnicodeFlag) {
-                return decode_unicode(s, len, rawmode, encoding);
+                return decode_unicode(s, len, rawmode, c->c_encoding);
         }
 #endif
-        need_encoding = (encoding != NULL &&
-                         strcmp(encoding, "utf-8") != 0 &&
-                         strcmp(encoding, "iso-8859-1") != 0);
+        need_encoding = (c->c_encoding != NULL &&
+                         strcmp(c->c_encoding, "utf-8") != 0 &&
+                         strcmp(c->c_encoding, "iso-8859-1") != 0);
         if (rawmode || strchr(s, '\\') == NULL) {
                 if (need_encoding) {
 #ifndef Py_USING_UNICODE
@@ -3310,7 +3313,7 @@ parsestr(const char *s, const char *encoding)
                         PyObject *v, *u = PyUnicode_DecodeUTF8(s, len, NULL);
                         if (u == NULL)
                                 return NULL;
-                        v = PyUnicode_AsEncodedString(u, encoding, NULL);
+                        v = PyUnicode_AsEncodedString(u, c->c_encoding, NULL);
                         Py_DECREF(u);
                         return v;
 #endif
@@ -3320,7 +3323,7 @@ parsestr(const char *s, const char *encoding)
         }
 
         return PyString_DecodeEscape(s, len, NULL, unicode,
-                                     need_encoding ? encoding : NULL);
+                                     need_encoding ? c->c_encoding : NULL);
 }
 
 /* Build a Python string object out of a STRING atom.  This takes care of
@@ -3333,11 +3336,11 @@ parsestrplus(struct compiling *c, const node *n)
         PyObject *v;
         int i;
         REQ(CHILD(n, 0), STRING);
-        if ((v = parsestr(STR(CHILD(n, 0)), c->c_encoding)) != NULL) {
+        if ((v = parsestr(c, STR(CHILD(n, 0)))) != NULL) {
                 /* String literal concatenation */
                 for (i = 1; i < NCH(n); i++) {
                         PyObject *s;
-                        s = parsestr(STR(CHILD(n, i)), c->c_encoding);
+                        s = parsestr(c, STR(CHILD(n, i)));
                         if (s == NULL)
                                 goto onError;
                         if (PyString_Check(v) && PyString_Check(s)) {

Python/future.c

@@ -35,6 +35,8 @@ future_check_features(PyFutureFeatures *ff, stmt_ty s, const char *filename)
 			ff->ff_features |= CO_FUTURE_WITH_STATEMENT;
 		} else if (strcmp(feature, FUTURE_PRINT_FUNCTION) == 0) {
 			ff->ff_features |= CO_FUTURE_PRINT_FUNCTION;
+		} else if (strcmp(feature, FUTURE_UNICODE_LITERALS) == 0) {
+			ff->ff_features |= CO_FUTURE_UNICODE_LITERALS;
 		} else if (strcmp(feature, "braces") == 0) {
 			PyErr_SetString(PyExc_SyntaxError,
 					"not a chance");

Python/import.c

@@ -818,11 +818,12 @@ parse_source_module(const char *pathname, FILE *fp)
 {
 	PyCodeObject *co = NULL;
 	mod_ty mod;
+	PyCompilerFlags flags;
 	PyArena *arena = PyArena_New();
 	if (arena == NULL)
 		return NULL;
 
-	mod = PyParser_ASTFromFile(fp, pathname, Py_file_input, 0, 0, 0, 
+	mod = PyParser_ASTFromFile(fp, pathname, Py_file_input, 0, 0, &flags, 
 				   NULL, arena);
 	if (mod) {
 		co = PyAST_Compile(mod, pathname, NULL, arena);

Python/pythonrun.c

@@ -774,8 +774,11 @@ PyRun_InteractiveLoopFlags(FILE *fp, const char *filename, PyCompilerFlags *flag
 #define PARSER_FLAGS(flags) \
 	((flags) ? ((((flags)->cf_flags & PyCF_DONT_IMPLY_DEDENT) ? \
 		      PyPARSE_DONT_IMPLY_DEDENT : 0) \
-		    | ((flags)->cf_flags & CO_FUTURE_PRINT_FUNCTION ? \
-		       PyPARSE_PRINT_IS_FUNCTION : 0)) : 0)
+		    | (((flags)->cf_flags & CO_FUTURE_PRINT_FUNCTION) ? \
+		       PyPARSE_PRINT_IS_FUNCTION : 0) \
+		    | (((flags)->cf_flags & CO_FUTURE_UNICODE_LITERALS) ? \
+		       PyPARSE_UNICODE_LITERALS : 0) \
+		    ) : 0)
 #endif
 
 int
@@ -1390,11 +1393,12 @@ Py_SymtableString(const char *str, const char *filename, int start)
 {
 	struct symtable *st;
 	mod_ty mod;
+	PyCompilerFlags flags;
 	PyArena *arena = PyArena_New();
 	if (arena == NULL)
 		return NULL;
 
-	mod = PyParser_ASTFromString(str, filename, start, NULL, arena);
+	mod = PyParser_ASTFromString(str, filename, start, &flags, arena);
 	if (mod == NULL) {
 		PyArena_Free(arena);
 		return NULL;
@@ -1411,10 +1415,16 @@ PyParser_ASTFromString(const char *s, const char *filename, int start,
 {
 	mod_ty mod;
 	perrdetail err;
-	node *n = PyParser_ParseStringFlagsFilename(s, filename,
+	int iflags;
+	iflags = PARSER_FLAGS(flags);
+
+	node *n = PyParser_ParseStringFlagsFilenameEx(s, filename,
 					&_PyParser_Grammar, start, &err,
-					PARSER_FLAGS(flags));
+					&iflags);
 	if (n) {
+		if (flags) {
+			flags->cf_flags |= iflags & PyCF_MASK;
+		}
 		mod = PyAST_FromNode(n, flags, filename, arena);
 		PyNode_Free(n);
 		return mod;
@@ -1432,9 +1442,15 @@ PyParser_ASTFromFile(FILE *fp, const char *filename, int start, char *ps1,
 {
 	mod_ty mod;
 	perrdetail err;
-	node *n = PyParser_ParseFileFlags(fp, filename, &_PyParser_Grammar,
-				start, ps1, ps2, &err, PARSER_FLAGS(flags));
+	int iflags;
+
+	iflags = PARSER_FLAGS(flags);
+	node *n = PyParser_ParseFileFlagsEx(fp, filename, &_PyParser_Grammar,
+				start, ps1, ps2, &err, &iflags);
 	if (n) {
+		if (flags) {
+			flags->cf_flags |= iflags & PyCF_MASK;
+		}
 		mod = PyAST_FromNode(n, flags, filename, arena);
 		PyNode_Free(n);
 		return mod;