I will explain this one with an example.
Supposing artist field exists:
$if2($meta(artist),no artist)
returns no artist in Mp3tag
returns value of $meta(artist) in foobar2000
It makes writing scripts more difficult.
In my view, this should be made to work as in foobar.
Can be written as ...
... boolean ...
$iflonger($meta(artist),,1,0)
... string ...
$iflonger($meta(artist),,$meta(artist),)
To tweak $if2 to expose the same behaviour when its argument is a text string output from $meta rather than a tag-field resp. tag-field content, there might be done some programming hard work to do.
DD.20110607.2010.CEST
Yes, it's not irreplaceable. Personally, I use $if(%artist%,$meta(artist),)
foobar2000 is closed source so there's probably no option to get it from there (?)