Backlinks that respect lists

#1

Hello,

I recently added backlinks to my wiki following the advice given here. Meaning that I’m using the following code with a $:/tags/ViewTemplatetag.

I noticed that this works, as long as the links to my tiddlers are created using conventional [[Linking]] but not is I use something like $list or {{{ [tag[List]] }}}

I’ve grown accustomed to using especially the latter synatx so i’m wondering if there is something I could do to adjust this backlink code to make it support generated lists.

Thanks!

<br>
<$list filter="[all[current]backlinks[]limit[1]has[title]]" variable=ignore>
<hr opacity=0.8>
incomming: <$list filter="[!is[system]all[current]backlinks[]sort[title]] -[is[current]]"><$link /> · </$list>
</$list>
#2

@welocom @Brin to the community.

As a rule if the tiddler is not “mentioned” (Eg [[tiddlername]]) in a particular tiddler, it does not become a backlink when only because it is listed as a result of the $list macro. There are ways to search “rendered” tiddlers, that is you wikify the text field before searching, but this is not very efficient, and since a given tiddler may be listed in many different ways, it could produce a lot of unwanted results.

  • keep in mind, depending on the filter used a given tiddler may, or may not, be listed if any one of the “variables” in a filter change, eg add remove a tag.
  • The same filter may be used in multiple tiddlers giving the same result, so in someways treating items “as listed buy a list widget” as “backlinks” is not what backlinks mean.

I am confident you may find another way to arrange your data which helps you discover the same thing.

  • Remember to look in the Info Button, where backlinks and references are listed.

You may add a step so if you want a backlink to a tiddler you make sure you add a link to it, not just because it is a member of a list.

  • If you want to ensure a backlink exists, but the link is not displayed in a tiddler you can do this ;
<span style.display="none">
[[Customising search results]]
</span>
  • You could add a feature to your listing to allow you to select any, or all items and add it/them to a list field, then you will see these in the listed tab of the info panel, and you can add not just backlinks but listed items ie instead of a filter of [all[current]backlinks[]] use a filter of [all[current]backlinks[]] [all[current]listed[]] +[sort[]] in your view template.

Let us know if you want more assistance.

#3

TLDR; It’s a performance problem at the moment.

To identify backlinks, the TW core needs to run the [[whole tiddler content]] through the first parsing step, where some information is created that this syntax links to a tiddler. We call this the “parse tree”.

So to calculate backlinks[] the TW core has to create a backlink-index by running every tiddler text through this first parsing step, if a special backlink is requested by the rendering mechanism.

If you use eg: <<list-links filter="[tag[something]]">> this fist parsing step doesn’t crate any information about the resulting list. It only creates info, that a filter [tag[something]] is used with the list-links macro. But this info isn’t worth too much, since filters are used all over the places for many different things and user defined macros can have any name. …

So it’s not possible to create a general algorithm that reveals the resulting list, except a full rendering of the HTML output and analysing this output for tiddler links. … So instead of 1 CPU heavy calculation, 4 heavy calculations would have to be done.

It’s needed to apply the first 2 steps from the rendering algorithm. Creating the parse-tree → create the widget-tree → analyse the widget-tree for backlinks or other stuff that may be interesting. … So it’s 3 heavy calculations and not 4 as I wrote above.

So in the end it’s a compromise in favour of performance.

Edit: After some more investigation I did change a paragraph above.

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#4

Thanks @Brin and welcome to the community.

This has come up many times before, and I’ve always given the same answer as @pmario: that performance would be a concern. However, I’ve never gone as far as experimenting to quantify the performance hit.

I’ve now done a very quick proof of concept, and as it turns out, it’s quite usable:

It needs some more work, but on the basis of the initial results I think we can be confident that this feature will be viable for the core.

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