Eric your answers are always fantastic. Thank you!
Respectfully, I think I speak for many here in saying we all hope you can
complete "InsideTiddlyWiki: The Missing Manuals" one day!
On Friday, January 4, 2019 at 11:19:12 AM UTC-6, Eric Shulman wrote:
>
> First, a bit of history: the code you quoted in your post is for
> TiddlyWiki Classic ("TWC"). The current version of TiddlyWiki ("TW" or
> "TW5") was completely re-written from the ground up several years ago to
> take advantage of modern browser tech such as HTML5. Additionally, in TWC,
> writing programmatic manipulations of tiddlers required either javascript
> programming or use of extra "plugins" to provide the needed syntax while in
> TW5, much of the programmatic syntax is provided natively within the TWCore.
>
> Now... on to your specific question. You wrote:
>
>> I would first filter the tiddlers by tag and then execute the batch edit
>> on this group. What I want to do is to put something at the begining of
>> each tiddler's tiddler (like adding prefix) without changing the rest of
>> the tittle. So in the end each tiddler will have the same prefix but
>> different rest of the title.
>
>
> To "filter tiddlers by tag", use the <$list> widget, like this:
> <$list filter="[tag[sometag]]">
>
> </$list>
>
> The <$list> widget uses the filter to find all the matching tiddlers and
> then loops through all the matches and sets the value of the
> <<currentTiddler>> variable to each title, in turn. By default, the
> <$list> widget will simply output the value of the <<currentTiddler>>
> resulting in the display of titles of all the matching tiddlers. To make
> the widget do something else, you need to add more syntax *within* the
> enclosing <$list>...</$list> that references the <<currentTiddler>>
> variable to act on each tiddler (e.g., setting a specified field value in
> the <<currentTiddler>>)
>
> For example, if you wanted to add/update a field named "matched" to
> "true", you would use the <$action-setfield> widget, like this:
> <$list filter="[tag[sometag]]">
> <$action-setfield $tiddler=<<currentTiddler>> matched="true"/>
> </$list>
>
> However, the above code is NOT enough to get the job done. Because the
> <$action-setfield> widget changes stored tiddler values, it requires a
> user-initiated "trigger" event to start the process. To achieve this, you
> can enclose the above <$list>...</$list> loop within a <$button> widget,
> like this:
> <$button>
> BUTTON TEXT
> <$list filter="[tag[sometag]]">
> <$action-setfield $tiddler=<<currentTiddler>> matched="true"/>
> </$list>
> </$button>
>
> So... for your use-case, you might think that the code would be something
> like:
> <$button>
> BUTTON TEXT
> <$list filter="[tag[sometag]]">
> <$action-setfield $tiddler=<<currentTiddler>> title="...NEW TITLE
> HERE..." />
> </$list>
> </$button>
>
> However... there are a few tricky details to consider:
>
> First, tiddler *titles* are not just display text, but are used to
> uniquely identify each tiddler. Thus, changing a title actually *copies*
> the existing tiddler content (all fields) to another tiddler with the
> specified new title and "renaming" a tiddler actually takes TWO actions:
> first change the title (creating a new tiddler), and then delete the
> tiddler with the old title, like this:
> <$button>
> BUTTON TEXT
> <$list filter="[tag[sometag]]">
> <$action-setfield $tiddler=<<currentTiddler>> title="..." />
> <!-- CREATES NEW TIDDLER -->
> <$action-deletetiddler $tiddler=<<currentTiddler>> /> <!-- REMOVES
> OLD TIDDLER -->
> </$list>
> </$button>
>
> The next problem is that TW5 syntax does not do direct text manipulation
> "in line", so assembling the desired new title (i.e., prepending some text
> to the beginning of the existing title) requires use of a little "helper"
> macro, like this:
> \define newTitle(prefix) $prefix$$(currentTiddler)$
> This macro takes one parameter, "prefix". The value of the parameter is
> rendered into the output using the $...$ syntax (i.e., "$prefix$"). The
> value of the current tiddler title is already available as a variable
> defined in the calling scope, and is referenced using the $(...)$.
>
> Putting it together, we get:
> \define newTitle(prefix) $prefix$$(currentTiddler)$
> <$button>
> BUTTON TEXT
> <$list filter="[tag[SOMETAG]]">
> <$action-setfield $tiddler=<<currentTiddler>> title=<<newTitle
> "SOMEPREFIX">> />
> <$action-deletetiddler $tiddler=<<currentTiddler>> />
> </$list>
> </$button>
>
> While this works, it would be nicer if we didn't "hard code" the button
> label, tag to match and the prefix to be added. To do this we can move the
> <$button> definition into a macro, and then invoke the macro, passing in
> the desired values, like this:
> \define newTitle(prefix) $prefix$$(currentTiddler)$
>
> \define addPrefix(label,tag,prefix)
> <$button>
> $label$
> <$list filter="[tag[$tag$]]">
> <$action-setfield $tiddler=<<currentTiddler>> title=<<newTitle
> "$prefix$">> />
> <$action-deletetiddler $tiddler=<<currentTiddler>> />
> </$list>
> </$button>
> \end
>
> <<addPrefix "ClickMe!" "sometag" "SomePrefix">>
>
> That should do it. Let me know how it goes.
>
> enjoy,
> -e
> Eric Shulman
> TiddlyTools.com: "Small Tools for Big Ideas!" (tm)
> InsideTiddlyWiki: The Missing Manuals
>
>
>
>
>
>
>
>
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