Re: python imports

Hi Andrey,

Sorry for the delay in replying.

Converting a tag generated by the grammar into something used in the 
buffer is a multi-step process.

The "tags" returned from the parser can have additional internal 
structure that represents a sort of "multi-tag" nature, or you can add 
any other data you need.

For example, in the C parser, the "name" of the variable:

int x,y,z;

is a list of 3 names, then the expand-tag function re-assembles that tag 
into 3 new tags.

In wisent/python.el you will see it is already monkeying around with the 
tags.  In your case, your rule:

    | FROM dotted_name_module IMPORT import_block


could have an action of:

     (:module-name $2  :import $4)

and then that could be stuck in as the "name" of the import.

Then back in python.el's semantic-python-expand-tag function could 
re-assemble all the :import parts with the :module-name and then deal 
those out into the different include tags.  You could also tag the 
import as a module instead of an include if that makes sense by changing 
the tag class to any symbol you want.   If you invent a new kind of tag 
class, you will need to update the tag formatters and other entries that 
try to convert tags into other formats.

If you feel more clever, you could stash the character locations of the 
2nd and 3rd module using $region inside the import_block, and then use 
that to give those tags different positions in the buffer.

I hope this helps!
Eric


On 09/29/2014 01:45 AM, Andrey Torba wrote:
> Hi all,
>
> In order to parse this python code:
>
> from a.b.c import (
>      x as xmodule,
>      y as ymodule,
>      z as zmodule,
>      )
>
> I created grammar:
>
> import_stmt
> ....
>    | FROM dotted_name_module IMPORT import_block
>      (identity $4)
>                          <- lisp code here which prepend "a.b.c" for
> each found module?
>    ;
>
> import_block
>    : PAREN_BLOCK
>      (let ((wisent-python-EXPANDING-block t))
>        (EXPANDFULL $1 import_block_as_name_list))
>    ;
>
> import_block_as_name_list
>    : LPAREN
>    | RPAREN
>    | import_as_name COMMA
>    | import_as_name RPAREN
>    ;
>
> As a result I get 3 modules: "x", "y", "z". How can i prepend "a.b.c"
> for each module?
> Also i think parser should create 3 global variables of type 'module':
> xmodule, ymodule, zmodule
>
> Thanks,
> -Andrey
>
>
> On 27 September 2014 16:14, Andrey Torba <[email protected]
> <mailto:[email protected]>> wrote:
>
>     Hello CEDET developers,
>
>     I'm investigating how to parse python's imports for the cases:
>
>     1. from ... import <classes> (works well in current implementation)
>        Example:
>        from a.b.c import Class1, Class2
>
>     2. from ... import <modules> (doesn't work)
>        Example:
>        from a.b.c import module1, module2
>
>        In this case parser must create:
>          - two INCLUDE-TAGs: 'a.b.c.module1' and 'a.b.c.module2'.
>
>     When we import something we don't know if it is module or class or
>     function... So include-tag should be 'a.b.c.something',
>     'a.b.c.class1', 'a.b.c.module1'. And then in the functions
>     'semantic-dependency-find-file-on-path' and
>     'semantic-tag-include-filename' we can guess which file to open:
>        - a/b/c/something.py
>        - a/b/c.py   class:something
>        - a/b/c/__init__.py    class:something
>
>     My question is: how can i build the grammar which makes 2 include
>     tags from the string: 'from a.b.c import module1, module2'. I need
>     to remember context ('a.b.c') and then build a full module path
>     (format "%s.%s" "a.b.c" "module1") ?
>
>     Thanks,
>     -Andrey
>
>
>
>
> --
> Regards, Andrey
>
>
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