associating bookmarks with paragraphs

associating bookmarks with paragraphs

[Michael Maurer]

as far as I know, the bookmark option is tied to a line number. is it
possible to associate
it with a paragraph, so when you cut and paste the paragraph to a
different position in
your document, the bookmark moves with it?

or maybe there's a different function in place which is more
appropriate for that
purpose.

Re: associating bookmarks with paragraphs

[Eric Abrahamsen]

Michael Maurer <maurer.michael@gmail.com> writes:

> as far as I know, the bookmark option is tied to a line number. is it
> possible to associate
> it with a paragraph, so when you cut and paste the paragraph to a
> different position in
> your document, the bookmark moves with it?

Bookmarks are implemented with markers, which do move with the
surrounding text. Did you try your cut and paste test with a marker in a
paragraph? The marker should move with it.

When you save them, they're saved as absolute positions in the file, but
even then some textual context is saved with them, to maximize the
changes that the bookmark can be restored correctly.

Eric

RE: associating bookmarks with paragraphs

[Drew Adams]

> as far as I know, the bookmark option is tied to a line
> number. is it possible to associate it with a paragraph,
> so when you cut and paste the paragraph to a different
> position in your document, the bookmark moves with it?

Emacs bookmarks (but perhaps not Org or EWW "bookmarks" -
can't speak for those) can bookmark pretty much anything.

By default, they bookmark a single position in a buffer,
typically a file buffer, not a line number.

The position is recorded, but so (by default) are some
text before and after the position.  If, when you jump
to a bookmark, the bookmarked position is not between
such text snippets then Emacs tries to reposition the
bookmark position, by searching forward and backward
for those saved text sequences (context).

It's not clear to me what you want to bookmark:

(1) A snippet of text that you (by jumping to the
    bookmark) paste here and there?
(2) Automatic relocation of a bookmarked position
    (e.g. of a paragraph)?
(3) Something else?

1. If you use Bookmark+ then you can do #1 by using a
snippet bookmark.  That records a snippet of text (e.g.
your paragraph), and when you jump to the bookmark that
text gets copied to the `kill-ring', so you can paste
it anywhere.

You can create (set) a snippet bookmark using command
`bmkp-set-snippet-bookmark', bound by default to
`C-x p c M-w' (bookmark-creation commands are put on
prefix key `C-x p c', by default).

You can jump to (i.e., use) a snippet bookmark using
command `bmkp-snippet-to-kill-ring', bound by default
to `C-x j M-w' (bookmark-jump commands are put on
prefix key `C-x j', by default).

(Or you can jump to it using the ordinary command
`bookmark-jump', which is bound by default to `C-x j j'.
But in that case the available bookmark-name completion
candidates are all bookmarks, not just snippet bookmarks.)

But you also say "so when you cut and paste the paragraph
to a different position in your document, the bookmark
moves with it."  That's unclear - makes no sense to me.
When you use a snippet bookmark the bookmarked snippet of
text becomes available for pasting.  When you paste that
text no bookmark is created in the buffer where you paste
it.  What bookmark do you want to "move with" the pasted
text?

2. But maybe you meant something completely different.
Maybe meant only that you want to bookmark the position
of a paragraph and then jump to that later, and have that
jump be accurate even if that paragraph has been moved
to a different location in your buffer/file?

If that's all you're asking then the answer is yes, that's
what Emacs does already - see above, about automatically
relocating a bookmarked position by searching for its
recorded context.

However, if the recorded context is no longer relevant
at all then Emacs won't be able to relocate the new
position accurately.

There is another possibility that can help here.  With
Bookmark+ you can bookmark not only a single position,
with its surrounding context, but two positions, with
their surrounding context.

This happens if you bookmark the active region, i.e.,
select your paragraph before bookmarking it.

If option `bmkp-use-region' is non-nil (the default)
then when you jump to a bookmark that records the
region (beginning and end positions, and surrounding
text), the targeted text that you jump to is highlighted
as the active region.

---

You can also define your own region handler for
bookmarks that record regions.  (This is in addition to
being able to define bookmark handlers.)  Use option
`bmkp-handle-region-function' for this.  As one example,
command `bmkp-region-jump-narrow-indirect-other-window'
binds the option to a function that narrows the targeted
region in a cloned indirect buffer.  (You need library
`narrow-indirect.el' for that command.)

https://www.emacswiki.org/emacs/BookmarkPlus

Re: associating bookmarks with paragraphs

[Michael Maurer]

On Thu, 6 Dec 2018 at 17:42, Drew Adams <drew.adams@oracle.com> wrote:
... snip ...
> 2. But maybe you meant something completely different.
> Maybe meant only that you want to bookmark the position
> of a paragraph and then jump to that later, and have that
> jump be accurate even if that paragraph has been moved
> to a different location in your buffer/file?
>
> If that's all you're asking then the answer is yes, that's
> what Emacs does already - see above, about automatically
> relocating a bookmarked position by searching for its
> recorded context.
>
> However, if the recorded context is no longer relevant
> at all then Emacs won't be able to relocate the new
> position accurately.
>
> There is another possibility that can help here.  With
> Bookmark+ you can bookmark not only a single position,
> with its surrounding context, but two positions, with
> their surrounding context.
>
> This happens if you bookmark the active region, i.e.,
> select your paragraph before bookmarking it.
>
> If option `bmkp-use-region' is non-nil (the default)
> then when you jump to a bookmark that records the
> region (beginning and end positions, and surrounding
> text), the targeted text that you jump to is highlighted
> as the active region.
>

Yes, this is what I was aiming at. I'll give it a try.
Just one question: How is Emacs able to determine the relevancy of
context? I guess this only works with writing code? Doesn't this go
into semantics? I'm probably mistaking "context" for something far
more complicated here.

RE: associating bookmarks with paragraphs

[Drew Adams]

> Yes, this is what I was aiming at. I'll give it a try.
> Just one question: How is Emacs able to determine the relevancy of
> context? I guess this only works with writing code? Doesn't this go
> into semantics? I'm probably mistaking "context" for something far
> more complicated here.

As I said, the bookmark records text immediately before and after the bookmarked position (or positions, if recording a region).

When you jump to a bookmarked position, it looks for a match of the recorded text that was before and after the recorded position.  If a match is found elsewhere (not at the recorded position) then it jumps to that found match position and asks you if you want to record that (i.e., update the bookmarked position and context text).