SF patch #1438387, PEP 328: relative and absolute imports.

 - IMPORT_NAME takes an extra argument from the stack: the relativeness of
   the import. Only passed to __import__ when it's not -1.

 - __import__() takes an optional 5th argument for the same thing; it
   __defaults to -1 (old semantics: try relative, then absolute)

 - 'from . import name' imports name (be it module or regular attribute)
   from the current module's *package*. Likewise, 'from .module import name'
   will import name from a sibling to the current module.

 - Importing from outside a package is not allowed; 'from . import sys' in a
   toplevel module will not work, nor will 'from .. import sys' in a
   (single-level) package.

 - 'from __future__ import absolute_import' will turn on the new semantics
   for import and from-import: imports will be absolute, except for
   from-import with dots.

Includes tests for regular imports and importhooks, parser changes and a
NEWS item, but no compiler-package changes or documentation changes.

1 files changed, 10 insertions, 2 deletions

diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index 3218b60..07de6cb 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -120,6 +120,7 @@ PyTypeObject *ImportFrom_type;
 char *ImportFrom_fields[]={
         "module",
         "names",
+        "level",
 };
 PyTypeObject *Exec_type;
 char *Exec_fields[]={
@@ -485,7 +486,7 @@ static int init_types(void)
         Import_type = make_type("Import", stmt_type, Import_fields, 1);
         if (!Import_type) return 0;
         ImportFrom_type = make_type("ImportFrom", stmt_type, ImportFrom_fields,
-                                    2);
+                                    3);
         if (!ImportFrom_type) return 0;
         Exec_type = make_type("Exec", stmt_type, Exec_fields, 3);
         if (!Exec_type) return 0;
@@ -1118,7 +1119,8 @@ Import(asdl_seq * names, int lineno, PyArena *arena)
 }
 
 stmt_ty
-ImportFrom(identifier module, asdl_seq * names, int lineno, PyArena *arena)
+ImportFrom(identifier module, asdl_seq * names, int level, int lineno, PyArena
+           *arena)
 {
         stmt_ty p;
         if (!module) {
@@ -1134,6 +1136,7 @@ ImportFrom(identifier module, asdl_seq * names, int lineno, PyArena *arena)
         p->kind = ImportFrom_kind;
         p->v.ImportFrom.module = module;
         p->v.ImportFrom.names = names;
+        p->v.ImportFrom.level = level;
         p->lineno = lineno;
         return p;
 }
@@ -2202,6 +2205,11 @@ ast2obj_stmt(void* _o)
                 if (PyObject_SetAttrString(result, "names", value) == -1)
                         goto failed;
                 Py_DECREF(value);
+                value = ast2obj_int(o->v.ImportFrom.level);
+                if (!value) goto failed;
+                if (PyObject_SetAttrString(result, "level", value) == -1)
+                        goto failed;
+                Py_DECREF(value);
                 break;
         case Exec_kind:
                 result = PyType_GenericNew(Exec_type, NULL, NULL);