Issue 66817

Summary: HARD LINKS as References
Product: Calc Reporter: discoleo <discoleo>
Component: codeAssignee: AOO issues mailing list <issues>
Status: CONFIRMED --- QA Contact:
Severity: Trivial    
Priority: P3 CC: issues
Version: OOo 2.0.2   
Target Milestone: ---   
Hardware: All   
OS: All   
Issue Type: FEATURE Latest Confirmation in: ---
Developer Difficulty: ---
Issue Depends on:    
Issue Blocks: 80139    

Description discoleo 2006-06-28 11:40:58 UTC
References and HARD LINKS
-------------------------

Most of the time I only need to work with a subset of the data from a worksheet.
To ease the work with very complex sheets, I copy that particular portion to a
new sheet. In addition, if the original data might change, making references to
the original data (instead of copying) is needed.

However, one limitation of this strategy is, that I cannot make changes within
the copies AND have the changes saved in the original record.

Suppose, we have a master sheet containing 10 subsets of (overlapping) data. I
will create 10 sheets to analyse those subsets, but I may detect an error
somewhere or need to recalculate some cells. It becomes a mess to make the
changes everywhere, even if we've used references to the original data in those
10 new sheets (as I still would need to find the specific cell in the original
mastersheet).

Another limitation is when referencing a cell containing a formula:
 -- suppose we write a formula in A1:
 = SUM(...) and we reference cell B1 to point to A1 (=A1). What we have in B1 is
the value from evaluating the SUM, NOT the formula itself. If we copied the cell
A1 to B1, any changes in B1 still wouldn't be reflected in the original formula
(in the A1 cell).

A very nice feature would be to have HARD LINKS the same way as under UNIX. The
advantage over usual references would be, that this is indeed an alias to the
original cell and any changes in a hard linked cell would be (actually) applied
to the original cell. (The features I will discuss would position it somewhere
more between true hard links and soft links.)

Some useful commands with hard linked cells would be:
 - delete hard link: remove the hard link (without deleting the original cell)
 - edit hard link: change the location the reference is pointing to
 - make local copy: remove hard link AND copy the content of the original cell
to the local cell ("make a simple reference to the cell (=cell)"/ "copy the
value of the cell"  (like in paste special) / or "copy the formula", depending
on an additional option)
 - jump to original: move cursor to the original cell
Comment 1 frank 2006-07-26 14:31:56 UTC
So this is basically the re-invention of the DDE feature from Windows but in
both directions.

IMHO not possible to implement without big changes, but requirements have to decide.

Frank
Comment 2 discoleo 2006-08-10 18:47:15 UTC
HARD LINKS are such a fundamental concept, that it must be implemented. But it
may be difficult now, however I would like to be constructive, therefore:

Although it might be difficult to implement it now, lets think more thoroughly
about the requirements and plan for future implementation:
 - the worksheet is probably currently a plain construction, which does not
allow hard links. This will probably pose numerous difficulties in the future,
too, because it does NOT allow to extend the functionality anyhow
 - there should be a timely plan to move from this simple plain sheet to
something more advanced
 - I do NOT say make it more comlicated, but rather devise something ingineous,
yet simple (simple things are the best)
 - there are some concerns about efficiency and memory-usage of the sheets
(posted somwhere on this site), so a more thorough thought on these issues is
warranted

My second idea is aimed to envisage a possible solution/help
 - UNIX OS's have hard-links in their FS
 - could an expert on UNIX FS help us to devise a more advanced worksheet
implementation?
 - my idea: consider any cell as a 'file' and the FS structure the structure of
our sheet
 - beyond hard links, we could implement in this way even more powerful features
(like references to other files, databases, URLs and whatever exists)
Comment 3 stx123 2007-01-29 11:26:17 UTC
let's reconsider the target...