Re: how to convert VB scripts to Gnumeric python

Copying would be a helpful thing. I ran into similar problems. There is 
a workaround.

My copy/paste operation core (sorry, this is c/p from my application so 
no setup code shown):

                         cell = sheet.cell_fetch(col, row)
                         if cell is not None:
                             d_cell = d_sheet.cell_fetch(dest_col, dest_row)
                             # For whatever reason, copying/duping value 
doesn't work, so we use other methods
                             if (debug > 0): print dest_col, dest_row
                             v = cell.get_rendered_text()
                             d_cell.set_text(v)
                             # This works but generates tons of 
gnm_style_unref errors
                             style = cell.get_style()
                             d_sheet.style_set_pos(dest_col, dest_row, 
style)

d_sheet, d_cell is the destination to copy to.

You essentially have to work with parts of a cell.

I can probably help with the introspection annotations, as you've 
already seen from the
patches I sent privately. I think if certain core functions are done 
first it will enable development
that would uncover other problems.

I have a personal development note document I will share here, since 
apparently rough drafts are OK to some of you and hint at problems:

Gnome Introspection notes
  - not part of the application
  - used scanner driven code
  - comments are code
  - function names influence introspection interface
  - names with "new" mostly result in constructor interfaces that return 
full-ownership objects that are easily usable.
  - Comments may not export usable interface and this will not show up 
as a bug in the application. e.g. allow-none/nullable optional values. 
(* I previously described this about inserting "allow-none" in the 
defintions)

  https://wiki.gnome.org/Projects/GObjectIntrospection#Annotation_System
  https://wiki.gnome.org/Projects/GObjectIntrospection/Annotations

Python GI API Reference
https://lazka.github.io/pgi-docs/


Python and introspection
  - Applications are C, python is not
  - Objects needs to be converted between the two, normally transparent 
but sometimes results in unexpected behavior.


  Memory Management
  - not all objects get exported in a directly usable way
  - in .gir file, object definitions tagged return-value 
transfer-ownership="full" are directly usable python objects
  - other objects may need reference or memory management and can 
trigger segfaults




On 04/11/2018 04:42 PM, Morten Welinder wrote:
> I tried to write a script to do some basic operations, but I 
> immediately hit problems in introspection
> and/or pygobject.  Specifically, something gets terminally confused 
> over sheet_cell_set_value
> leading to a double-free.  Even if they fix that right now, it's 
> going to be years before stable distributions
> will see the fix.
>
> In this particular case I might be able to paper over the problem by 
> interposing a function that copies
> its argument instead of taking ownership.  That'll slow down python a 
> bit, but if you're using python
> you're probably not that much in a hurry.
>
> The key to getting parts of Gnumeric available via python is to have 
> accurate introspection annotations
> for the relevant APIs.  If anyone feels like helping with that, it 
> would be appreciated.
>
> Morten
>
>
>
>
>
> _______________________________________________
> gnumeric-list mailing list
> [email protected]
> https://mail.gnome.org/mailman/listinfo/gnumeric-list

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