[tw5] Cannot use a variable from a filter. Can someone help me ?

Hi,

I’m trying to run the following code (at the end of the message) which uses a variable called ‘target’ (that contains the current date) into a filter called todayfilter
I’ve tested the todayfilter this way

<$vars todayfilter="[get[task_date]compare:string:eg[2021-08-22]]">
and this works (I mean the list <$list filter="[regexp[db___]!sort[task_start_time]filter]"> works fine

\define now_val()
<$vars now_date=<>>
<$vars target={{{ [<now_date>] }}}>
<>

<$vars todayfilter="[get[task_date]compare:string:eg[]]">

<$list filter="[regexp[db___]!sort[task_start_time]filter]">
Date Project Task Start Stop
  //Number of tiddlers// ''<$count filter="[regexp[db___]filter]"/>''
<$link><$view field="task_date"/> <$view field="tags"/> <$view field="task_comment"/> <$view field="task_start_time"/> <$view field="task_end_time"/>

\end

<<now_val>>