Extending the IS and All Operator for custom definitions

[AnthonyMuscio]

The Is (and all) Operator currently provide number of categories
eg blank tag shadow tiddler etc...

I can imagine that the is operator simply applies a filter to achieve its desired result.

With the new "filter" operator, we can now say filter{task} where the "task" tiddler may contain
[!is[system]object-type[task]]
Thus we could list all tasks with;

<$list filter="[filter{task}]">

</$list>

We could also test if a task is active with a filter in a tiddler "active"
[!has[done-date]!has[archive-date]]
Thus we could list all tasks with;

<$list filter="[filter{task}filter{active}]">

</$list>

Suggested change;
Allow the provision of new names to be used in the IS and All operators with a corresponding filter;
eg
task filter=[!is[system]object-type[task]]
active filter=[!has[done-date]!has[archive-date]]

Then a list can use;

<$list filter="[is[task]is[active]]">

</$list>

Why?
Filter definitions can be made more readable; and a designer can embed the logic of his/her solution in a set of predefined filters that can be made use of, in simple IS and ALL operators. This allows the user of such a solution then to generate new lists and queries within the tiddlywiki using a set of predefined filters.

Regards
Tony

[AnthonyMuscio]

Of if so Defined

<$list filter="[all[active-task]]">

</$list>

[AnthonyMuscio]

Further
IS would use [all[current]] ALL would use [all[]]