Assign analytic distribution on account entry line

I needed to register some expenses through an account move and wanted to assign the corresponding analytic account to the expense move line. However this expense is “shared” among various analytic accounts. Normally I will pick an analytic account distribution to do the job, but in the move line analytic section, only accounts can be chosen and not distributions. Is this a something done on purpose or it is and unfinished feature that can be implemented later?

The distribution account is only for upper document like invoice, sale or purchase.
At the level of the move line it is only normal accounts are allowed.
The distribution accounts are just a shortcut to distribute at the move line level.

Thank you for the answer. Then what would be the solution to make it easier for the user to assign the analytic normal accounts without having to compute each portion by hand and input each portion manually. Do you think it is possible and a good approach that I implement the distribution code to do the actual distribution computation when the analytic lines are created instead at the account move line level? (This is so that I can use the distributions at the account move line) Would this mess up the analytic accounting reports or processing?

Having to fill analytic after the move has been created should be a very rare case. The analytic should be filled on the document creating the move because it is were the business data is known.
So I do not think we need to create tools for rare case.

Ohh, no… I did not meant filling the analytic after the move. Let me explain it:
As I understand the analytic lines are separate from the account move lines and they store amount information (debit and credit) independently. So when the move is “posted” the analytic lines are created based on the analytic account information assigned to the account move line. So only at that moment if the line has a distribution assigned instead of a normal account, then the corresponding portions are computed and the analytic lines created for each portion. A move that is posted, cannot be modified, and so this is too for the analytic account lines created for that account move line. Both operations happen at the posting.

This is the approach I had in mind when I ask if I could implement the distributions at the account move line level.

There is no such information on move line.
It is the document like the invoice that create the analytic lines using the accounts defined on them.

This is false, the analytic lines can be modified, created or deleted at any time.

So as I said there is no point to do that at the move line level because the analytic should have been filled by the document creating the move like the invoice.
I see no point to add a new mechanism because users are skipped the proper way. If they skip they know they will have to do the hard job manually.

Personnally, I would have the need to use distributed account on move directly: for example I am creating Move for recording salary slip for employees, and depending the employee I need to fill analytic with several analytic account (employee working in several sectors of activity for example).

currently i am using a proteus script to affect the analytic accounts to the move without too much pain.

For me this is a need because we do not have yet the proper document for payroll. Once such document exist it will be easy to add an analytic entry on the employee or payroll.

Pardon my ignorance, you were right! I did not read through the code, so what I had in mind cannot be implemented. I think I will try to find a solution going with the analytic rules. Maybe by adding some additional criteria I could have have my expense associated to a distribution and generate the proper analytic lines.