Hi Xavier, Tony,
thanks that looks very helpful I'm going to study that and have some fun !
Cheers
Eric
On Thursday, May 21, 2020 at 3:47:30 AM UTC+4, TonyM wrote:
>
> Eric
>
> The first quick tip about recursive processes in tiddlywiki is if a filter
> is used to call a level it usually describes a list of titles or values
> which are themselves limited in number, that is they are exhausted
> eventually and the recursive process returns to the previous call.
>
> here is an example I shared sometime ago, intentionally made into two
> macros so the user can find where to insert modifications
>
> \define each-other-level(filter)
> <li><$link to=<<currentTiddler>> ><$text
> text=<<currentTiddler>>/></$link></li>
> <ul>
> <$list filter="$filter$">
> <<each-other-level $filter$>>
> </$list>
> </ul>
> \end
> \define first-level(filter)
> <ul>
> <$list filter="$filter$">
> <<each-other-level $filter$>>
> </$list>
> </ul>
> \end
>
> Start in TableOfContents<br>
> <$tiddler tiddler="TableOfContents">
>
> <<first-level "[is[current]tagging[]]">>
>
> </$tiddler>
>
>
> Although quite complex one insight for the adventerouse into recursive
> processes in tiddlywiki is the TOC macros which obviously use recursion
> see $:/core/macros/toc
>
> Of course if you iterate a hierarchy you need to be careful of entering an
> infinite loop if one item has a child that is above it in the hierarchy "it
> may be its own grandfather".
>
> Bimlases Kin filter is good at turning hierarchies into a flat list of
> titles (among other things) so this can simplify code.
>
> I think using filters can make recursion easy in TiddlyWiki because it
> naturally limits the iterations, but if you look in my example above, in
> each-other-level you could add logic to skip calling itself in particular
> conditions.
>
> Regards
> Tony
>
>
>
> On Wednesday, May 20, 2020 at 7:01:17 PM UTC+10, Eric N. wrote:
>>
>> Hi Tony,
>> Sorry for the late answer...
>>
>> You are right, I am sometimes confusing this google group with a
>> Tiddlywiki FAQ + code review + ideas box + many other things ;-)
>>
>> My main question was not really about how to solve my specific problem,
>> but the generic problem of using recursive macros and if then else nested
>> statements in the macros.
>>
>> I'm used to using functions, and in those a simple "return value" will
>> skip the rest of the function code. Clear and short code.
>>
>> In macros, I'll display the output "value" but then I have to make sure
>> that the rest of the code is not executed, i.e. that it doesn't display and
>> execute other stuff. That is, I need to make sure that I'll reach the
>> "\end" of the macro without executing anything - as if I did return a value
>> in a function.
>>
>> Because of this "as if", i.e. because I have to make sure I'll reach the
>> end of the macro code without executing anything once I've output what I
>> wanted, I have to use a lot of if then else statements, nested, i.e. a lot
>> of "<$list filter=...>" statements.
>>
>> And because of that, the code I write seems to me hard to read, hard to
>> understand later on and hard to maintain. (cf nested lists in my original
>> post)
>>
>> And so, this is so surprising to me that I end up with a code I am not
>> comfortable with, not happy with, that I wondered if there was something I
>> completely missed with macros and nested if-then-else statements.
>>
>>
>> If that's just the way it works, then OK... Otherwise I'd be happy to
>> learn how to produce a better code :)
>>
>> Best,
>> And have a good day everyone !
>>
>>
>> Eric
>>
>>
>> On Thursday, May 14, 2020 at 3:38:20 PM UTC+4, TonyM wrote:
>>>
>>> Eric
>>>
>>> Love the way you are thinking some of us have done similar things. I
>>> think it is as easy as anywhere to do this kind of thing. Of course it has
>>> its own complexity. I would look at solving component issues then bring
>>> them together in a solution.
>>>
>>> I can help more later but consider a custom new here button which passes
>>> more to the child tiddler than a tag. Its easy to creat a tiddler with
>>> additional fields. I have posted on setting context before but a simple
>>> fieldname={{!!fieldname}} in the creat tiddler can do a lot.
>>>
>>> I will see what other tips I can share when next at my desktop.
>>>
>>> Regards
>>> Tony
>>>
>>>
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