mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-07-24 11:44:31 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 8

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

Browse source 
- 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.
This commit is contained in:
Thomas Wouters 2006-02-28 16:09:29 +00:00
parent d3188639c3
commit f7f438ba3b
20 changed files with 270 additions and 73 deletions
Download patch file Download diff file Expand all files Collapse all files

39
Modules/parsermodule.c
View file

@ -1792,27 +1792,42 @@ validate_import_name(node *tree)
&& 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);
}