[Tech support] Format string OR conditional

[Slider-Whistle]

Hi, sorry if this is already documented somewhere, but is it possible for one keyword to be valid, only if the previous keyword is invalid? (false, "None", etc.) Basically something like the equivalent of sh's "||" operator.
As for the specific use case, I like to download e-hentai galleries into directories named after "title_jpn" where possible, but some uploaders forget to use that field, so in those cases I'd like for gallery-dl to use "title" as a fallback.
I did some searching and found some information related to actual Python code, which I'm not sure how to apply to the config file, and an issue where you pointed out that some similar conditional logic has been implemented.

Possibly related issue: #1394

[mikf]

Alternatives in format strings can be specified with |: {title_jpn|title}
{title_jpn[:255]|title[:255]} to shorten titles longer than allowed is also possible.

if this is already documented somewhere

It isn't, together with a lot of other formatting options ...

[Slider-Whistle]

Thanks!