I see , thanks! that is a much better method to implement the idea
Mark S. 在 2020年12月12日 星期六下午8:53:02 [UTC] 的信中寫道：
> I suspect your usage would break the spirit of the JS rules, since it's
> using a macro to change TW content.
>
> But you could write a non-JS (i.e.wikitext) macro that would basically do
> the same thing. If the tiddler doesn't exist, it would show a button which,
> when clicked on, would create the tiddler. A button can be disguised as a
> link, if that's important to you.
>
>
>
> On Saturday, December 12, 2020 at 11:29:44 AM UTC-8 Leung arvin wrote:
>
>> I wish to implement the following functionality, using JS macro, defining
>> the macro with name M.
>>
>> Whenever I use a macro <<M tiddler_name : "New Tiddler">> , then it
>> creates a Tiddler with title "New Tiddler". Then the macro presents this
>> link [[New Tiddler]]. The point is that the macro will create the Tiddler
>> for me (with some starting content , customisable in JS) if none have
>> already been created.
>>
>> Example code would be:
>>
>> function run(tiddler_name){
>> - Check if wiki has tiddler with title tiddler_name
>> - If not, create a tiddler of title tiddler_name and content "default
>> content"
>> - Return [[tiddler_name]]
>> }
>>
>> I would like to know if this is safe. The documentation states:
>>
>> "Macros are just used to return a chunk of wikitext for further
>> processing. They should not make modifications to tiddlers in the wiki
>> store. The reason is that you cannott control when the macro is called; it
>> may be called repeatedly as part of refresh processing. So it is important
>> that macros do not have any other side effects beyond generating their
>> text."
>>
>> So this would break the no side effect rule. However, the idempotent
>> design means that subsequent calls to this macro should not have any side
>> effects.
>>
>> Will this potentially break stuff in unknown ways? I would also like to
>> know if there are other methods to achieve the same tasks in JS.
>>
>>
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