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.
diff --git a/Modules/parsermodule.c b/Modules/parsermodule.c
index 72df8c7..0dcb50f 100644
--- a/Modules/parsermodule.c
+++ b/Modules/parsermodule.c
@@ -1792,27 +1792,42 @@
&& validate_dotted_as_names(CHILD(tree, 1)));
}
+/* Helper function to count the number of leading dots in
+ * 'from ...module import name'
+ */
+static int
+count_from_dots(node *tree)
+{
+ int i;
+ for (i = 0; i < NCH(tree); i++)
+ if (TYPE(CHILD(tree, i)) != DOT)
+ break;
+ return i;
+}
-/* 'from' dotted_name 'import' ('*' | '(' import_as_names ')' |
+/* 'from' ('.'* dotted_name | '.') 'import' ('*' | '(' import_as_names ')' |
* import_as_names
*/
static int
validate_import_from(node *tree)
{
int nch = NCH(tree);
+ int ndots = count_from_dots(tree);
+ int havename = (TYPE(CHILD(tree, ndots + 1)) == dotted_name);
+ int offset = ndots + havename;
int res = validate_ntype(tree, import_from)
- && (nch >= 4)
- && validate_name(CHILD(tree, 0), "from")
- && validate_dotted_name(CHILD(tree, 1))
- && validate_name(CHILD(tree, 2), "import");
+ && (nch >= 4 + ndots)
+ && validate_name(CHILD(tree, 0), "from")
+ && (!havename || validate_dotted_name(CHILD(tree, ndots + 1)))
+ && validate_name(CHILD(tree, offset + 1), "import");
- if (res && TYPE(CHILD(tree, 3)) == LPAR)
- res = ((nch == 6)
- && validate_lparen(CHILD(tree, 3))
- && validate_import_as_names(CHILD(tree, 4))
- && validate_rparen(CHILD(tree, 5)));
- else if (res && TYPE(CHILD(tree, 3)) != STAR)
- res = validate_import_as_names(CHILD(tree, 3));
+ if (res && TYPE(CHILD(tree, offset + 2)) == LPAR)
+ res = ((nch == offset + 5)
+ && validate_lparen(CHILD(tree, offset + 2))
+ && validate_import_as_names(CHILD(tree, offset + 3))
+ && validate_rparen(CHILD(tree, offset + 4)));
+ else if (res && TYPE(CHILD(tree, offset + 2)) != STAR)
+ res = validate_import_as_names(CHILD(tree, offset + 2));
return (res);
}