[Idea] It is proposed to create if/then/else convenience functions also be usable with list and reveal

[pmario]

It is proposed to create if/then/else convenience functions also be usable with list and reveal

A main goal should be, that the new functions are "simpler" than a similar construction with the reveal-widget or the list-widget

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From: https://github.com/Jermolene/TiddlyWiki5/issues/6854

Indeed, but such a thing belongs in the core, or its own plugin, and wouldn't be appropriate for this docs plugin.

So should we create a PR using the condition plugin code?

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As far as I can remember, the widgets have to follow a specific syntax pattern to work as intended. eg: JS syntax used to describe the problem

// the following syntax is OK

if (var === true) {
// do something
} else {
// do something else 
}

// The following syntax in _wrong_

if (var === ture) {
// do something
} 
var x = y;
else {
// do something else 
}

In JS it's clear, that we get a syntax error.

But the same problem happens if we use "faulty syntax" in wikitext, which would be a new behaviour.

<!-- this does _not_ work -->
<$list filter="false">
<!-- do something -->
</list>
<br>
<$else> <!-- do something --> </$else>

This is a difference in behaviour of widgets, since the else-widget needs to "find" it's related sibling. ... I'm only 90% sure that I got the problem right. ... The plugins where created in 2017 ...

[Jermolene]

Thanks @pmario.

The condition plugin uses lateral dependencies between widgets (eg the <$else> widget being a sibling of the associated <$list> widget) which is not currently supported by the core; the existing core code rests on the assumption that a widget can be refreshed without affecting its siblings, just its children. Under the circumstances, the condition plugin does a great job of getting things working. But, if we were going to support lateral dependencies between widgets then there's a lot more that I'd want to do, such as heading counters, which would mean refactoring things more thoroughly.

There is an alternative to the lateral dependencies. For example:

<$if condition="...">
  <$then>
   ...
  </$then>
  <$else>
   ...
  </$else>
</$if>

[kookma]

Also worth to see this post and discussion by Jeremy https://talk.tiddlywiki.org/t/switch-case-construct/2234/13

[pmario]

From https://talk.tiddlywiki.org/t/switch-case-construct/2234/13

To clarify, I do not think that we need new widgets for if/then/else or switch/case; as TW_Tones has shown, the required logic can be performed with the list widget. I am interested in exploring new wikitext syntax that acts a shortcut for those widgets.

As a simple example:

\if [<currentTiddler>match[yes]]
{{Foo}}
\else
{{Bar}}
\endif

Or:

\switch [<currentTiddler>]
\case "something"
{{Foo}}
\case "else"
{{Bar}}
\endswitch

[pmario]

I did update the OP, with a main goal -- simplicity ...

I think, if the new construction is as complex as using "reveal" or "list" it doesn't make sense to create them.

[CodaCodr]

 <!-- this does work -->
<$list filter="false">
<!-- do something -->
</list>
<br>
<$else> <!-- do something --> </$else>

That doesn't work, it will produce:

$else widget must follow $if, $else-if, $reveal or $list.

I use these a lot, even so, I prefer @Jermolene's <$if><$then>... construct even though it would present me with a massive rewrite.

[pmario]

That doesn't work, it will produce:

Sorry ... The text in front of the example was right. but the example itself was a "copy paste error" . Fixed it in the post

[pmario]

close this one because it will be implemented in v5.3.2