[Texmacs-dev] Understanding paths

[skhilji]

I type the following:

<\body>
  This is a simple test <strong|with some strong text>. This is a simple test
  This is a simple test.\

  This line does not have any special content tags. This line does not have
  any special content tags. This line does not have any special content tags.
</body>


Then I did print_tree() on the edit tree.  After manually annotating it, here 
it is:

document
  (0)concat
    (0)(STRING) This is a simple test
    (1)strong
      (STRING) with some strong text
    (2)(STRING) . This is a simple test. This is a simple test. This is a 
simple test. This is a simple test. This is a simple test. This is a simple 
test.
  (1)(STRING) This line does not have any special content tags. This line does 
not have any special content tags. This line does not have any special content 
tags.  This line does not have any special content tags. This line does not 
have any special content tags.


After puting some code in edit_cursor_rep::cursor_move (SI dx, SI dy) to cout 
the cursor position, run the following experiment:

Put the cursor right after the word "STRONG" in the first paragraph in the 
TeXmacs window.  After the right arrow key, TeXmacs displays:

Cursor Position: [ 0, 1, 0, 17 ]

Looking at the edit tree, I would have expected [ 0, 1, 17 ] i.e only 3 items 
in the path.  I don't understand how we end up with 4 elements in the tree.

Another thing:

1)  Put the cursor right after the strong word "TEXT".  Hit the right arrow 
key.  TeXmacs displays: Cursor Position: [ 0, 1, 1 ].  I would have expected [ 
0, 2, 0 ].  We can never have the cursor at [0, 2, 0].  TeXmacs always begins 
at [0, 2, 1].

I have read the developers docs where it mentions about a ghost cursor.  From 
what I see above, it seems like there is a "ghost" edit tree item after the 
line:

    (1)strong
      (STRING) with some strong text

in the edit tree. i.e. the edit tree looks like:

    (1)strong
      (STRING) with some strong text
       <<GHOST>>


Can someone please elaborate on it a little more to clear it up.

Salman