How to format a link using tiddler fields in a list widget.

[vpl]

Hi,

I need the community help as I try to format a link to an external (pdf) ressource using tiddler fields. But I cannot achieve it ..

When I run the following list of song with a hard coded link to the external resource, it works

<$list filter="[!is[system]tag[song]sort[song_title]]">

* [ext[As a download pdf (android) |files/test.pdf]]

</$list>

Now when I try to customize the resource link using the tiddler 'book_fime_name' fields like that, It does not work ..

<$list filter="[!is[system]tag[song]sort[song_title]]">

* [ext[As a download pdf (android) |files/{{{ [<currentTiddler>get[book_file_name]] }}}]]

</$list>

Ir returns 

• As a download pdf (android) }}}]]

• As a download pdf (android) }}}]]

• As a download pdf (android) }}}]]

which is obviously not what I'm looking for ...

Any expert in the community to help me ?

I will appreciate

Regards