path: root/2022/captions/emacsconf-2022-eev--bidirectional-links-with-eev--eduardo-ochs--main.vtt

WEBVTT captioned by eduardo
Kind: captions:
Language: en-GB

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Hi! My name is Eduardo Ochs. I'm the author

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of an Emacs package called eev, and the name

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of this presentation is: "Bidirectional links

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in eev".

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Let me present things in a weird order,

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starting by the new feature, and then I'm

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going to explain the whole context.

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One of the main features that we are

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going to see here is this function here,

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M-x kla, and kla is a mnemonic for "kill

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Link to Anchor". Let me explain... let me

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demonstrate how it works. This thing here

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with the green angle brackets is an

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anchor, this thing between the green

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angle brackets is a tag of an

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anchor, and if I type M-x kla here

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it highlights this tag for a second and

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it says "Copied to the kill ring: blah

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blah blah..." and this thing here is a link.

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I can insert the link here, I

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can insert the link in my notes...

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and if I execute this thing this link

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here it goes to this anchor in this file.

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If you have a recent version of eev

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installed then trying this feature

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should be very easy...

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you just need to open the this file here,

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in which everything is defined, and then

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go to this section at the beginning of

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the file, and then run the three blocks

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of tests that are there.

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This block corresponds roughly to what

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we have just done...

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this other block

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is slightly different because it shows

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some variants of kla... one is with `f`

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instead of an `a` here, let me

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show how it works... if we type

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`M-x eeklf` or just `M-x klf`

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we get a link to this file that does not

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point to an anchor, and if we type

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`M-x klt` we get another kind of link that

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is a link to an anchor in the same

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file...

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and the third block

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is more interesting because it lets

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people create links to files that

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are elsewhere, and that do not have

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anchors in them...

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let me execute this... this will

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run this sexp here and display the

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target at the window at the right...

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this is one of the source files of Emacs.

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Let's imagine that I want to create a

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link to this string here... then I can

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type `M-x klfs`, and this will create a

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link to a file and to a string in that

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file. So if I type ENTER here

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it says: "Copied to the kill ring: ...\

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and this is a link to this file here,

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and to the first occurrence of this

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string in this file.

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So: how does this work (inside)?...

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when I was trying to write the documentation

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of this I tried to write a summary of

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how the algorithm works, and I failed and

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I tried again, and I failed again,

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several times... and then I gave up and I

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decided to write an intro - a tutorial,

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this one -

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that explains everything with lots of

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details, and with lots of sections

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with "Try it!"s, that

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have examples that you you can run to

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understand things, to examine how some

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functions work, how the data

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structures work, and so on...

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the problem is that sometimes we have

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several hyperlinks that point to the to

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the same file. Let me give an example.

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In the configuration in which I am now,

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in this file here... the old way of

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generating hyperlinks to this file

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with `find-here-links`

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will generate a temporary buffer

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like this, and then I would have to

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choose which one of these hyperlinks I

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find best, which one I prefer, and then

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copy it to my notes... so instead

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of choosing a hyperlink this thing here

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shows all the options.

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And in the new way, in `M-x kla`

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and friends, there's an algorithm that

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chooses the best short hyperlink by

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itself, and this algorithm is a bit hard

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to explain... let me demonstrate it here.

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Again, we have all these options here, of

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hyperlinks to this file...

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and if I type `M-x klf`

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it chooses one of them.

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And of course I can copy it to my notes,

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it's going to work, it's going to point

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to here... and so on.

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Well, the title of this presentation was

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"Bidirectional links with eev"... let me

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show what I mean by bi-directional

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hyperlinks, and how we can use this thing

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to create bidirectional hyperlinks

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very quickly.

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I will have to use a smaller font... let

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me open these two files here. This one at

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the left is a program in Haskell, and

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this one is a file with my notes on

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Haskell.

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How do I create a link from...

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to this file in Haskell

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to put it in this file here? I can put

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the cursor here, in any position

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after this anchor here, and type

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`M-x kla`...

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it copies this link here to the kill

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ring and then I can can go here and

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either insert it with C-y (yank), or

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insert it with `M-k kli`, that adds a

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comment prefix here.

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So this is a way to create a link from

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here to there in which every

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comment has to be given explicitly...

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but I also implemented a way to

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create the two links at the same time.

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I don't use it much, it's mostly for

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demos, because it's impressive, I wanted

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to show that in this presentation...

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Anyway, let me show it here. Note that

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that in this file here the point is

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here, in this file the point is here...

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My trick is going to create a link to

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this anchor and put it in this file, and

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it's going to create a link to this

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anchor and put it in this file...

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So, here it goes: `M-x kla2`... ta-da!

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it highlighted the true anchors for a

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second, and it created these things here

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and inserted them with the

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right prefixes, I mean, the right

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comment prefixes.

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And that's it!

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So... that's it. If you found this thing

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interesting just

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install a recent version of eev and run

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the tutorial, either with this thing here,

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`M-x find-kla-intro`, or by running

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this sexp, or open this file here in the

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eev directory, and follow the

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tutorials...

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most things that there are well

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documented, but the thing that I don't

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use much and that is mostly for demos,

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which is the the thing that creates

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bi-directional hyperlinks, is not yet

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well documented, but the rest is.

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So: that's it! Bye! Have fun! =)