Mohammad,
I some ways I built this so the empty message did not require a macro, to
keep all the logic in the one block.
I would imaging people would copy such a block as follows
<$list filter="[<casevariable>] ~[[::false]]" variable=case>
<$list filter="[<case>prefix[::false]]" variable=case>
Do this if no case value
</$list>
<$list filter="[<case>!prefix[::false]]" variable=case>
Do this for every case except empty/false
</$list>
<$list filter="[<case>prefix[caseone]]" variable=case>
Process "caseone"<br>
</$list>
<$list filter="[<case>prefix[casetwo]]" variable=case>
Process "casetwo"<br>
</$list>
<$list filter="[<case>prefix[casethree]]" variable=case>
Process "casethree"<br>
</$list>
<!-- Even this -->
<$list filter="[<case>prefix[casetwo]] [<case>prefix[casethree]]"
variable=case>
Process "casetwo" and "casethree"<br>
</$list>
</$list>
Then change add remove as needed for their application
However in the unlikely case people need to use "nested case statements or
reuse them, here is a Quick macro version
\define in-cases-of(case-filter)
<$list filter="$case-filter$ ~[[::false]]" variable=case>
<$list filter="[<case>prefix[::false]]" variable=case>
Do this if no case value
</$list>
<$list filter="[<case>!prefix[::false]]" variable=case>
Do this for every case except empty/false
</$list>
<$list filter="[<case>prefix[caseone]]" variable=case>
Process "caseone"<br>
</$list>
<$list filter="[<case>prefix[casetwo]]" variable=case>
Process "casetwo"<br>
</$list>
<$list filter="[<case>prefix[casethree]]" variable=case>
Process "casethree"<br>
</$list>
<!-- Even this -->
<$list filter="[<case>prefix[casetwo]] [<case>prefix[casethree]]"
variable=case>
Process "casetwo" and "casethree"<br>
</$list>
</$list>
\end
<<in-cases-of "[{!!tiddler-mode}]">>
Which still needs editing for the specific situation
CHanges most likely would be only
- Change the values for caseone casetwo and casethree to those you want
to use
- Add remove other responses to different case values or combinations
thereof.
Additional interesting patterns here
- The above method of passing filters to a macro as a parameter, allows
you to pass tiddler content, field content, literal values, variable values,
macronames etc.. which sometimes suddenly results in a macro for one
purpose suddenly be capable of another purpose.
In a similar way we can pass a filter to a macro as follows
\define my-macro(filter)
{{{ $filter$ }}}
{{{ $filter$ ||templatename}}}
\end
or
\define my-macro(filter template)
{{{ $filter$ }}}
{{{ $filter$ ||$templatename$}}}
\end
Once again all this is untested but based on experience.
Regards
Tony
On Saturday, July 27, 2019 at 2:39:30 PM UTC+10, Mohammad wrote:
>
> Hi Tony!
> This is great and needs some examples to explore the pros and cons!
> By the way as you said the application may vary case by case and a macro
> may not be a good option.
>
> --Mohammad
>
> On Saturday, July 27, 2019 at 4:18:31 AM UTC+4:30, TonyM wrote:
>>
>> Mohammad,
>>
>>
>>> We need to wrap inside a macro to present a construct like
>>>
>>> <<select-case condition array-of-cases>>
>>>
>>>>
>>>>
>>>
>> In someways I am suggesting you do not need to make a "select-case macro
>> " because the whole case structure including the empty case can be written
>> inside the one outer list object. Thus it may be included something like
>> this
>> {{invoice-total}}
>> where the case test various conditions and generates a result eg if tax
>> applies etc...
>>
>> However if you do want to make a macro as in your example the case
>> structure will still need to know how to handle your array-of-cases
>>
>> I would think its more like this;
>> \define if-else-test(filter)
>> <$list filter="[[$filter$]] ~[[::else]]" variable=case>
>> <$list filter="[<case>!prefix[::else]]" variable=case>
>> filter-not-empty do-this for each result
>> </$list>
>> <$list filter="[<case>prefix[::else]]" variable=case>
>> else do-that
>> </$list>
>> <!-- other cases if desired -->
>> </$list>
>> \end
>> <<if-else-test "filter">>
>> note: untested
>>
>> Regards
>> Tony
>>
>
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