Morten Høgholm skrev:
> It is used in a few cases such as
> 
> \def_long:Npn \tlp_if_in:NnTF #1#2{
>   \def_long:Npn\tmp:w ##1 #2 ##2\q_stop{
>     \quark_if_no_value:nFT{##2}
>   }
>   \exp_after:NN \tmp:w #1 #2 \q_no_value \q_stop
> }
> 
> If there was no FT variant, this function would either have to read
> the TF arguments twice or the quark test would have to be done
> manually.

Hmm... Isn't
   \quark_if_no_value:nFT{##2}
equivalent to
   \quark_if_no_value:nTF{##2}\use_arg_ii:nn\use_arg_i:nn
?
This neither reads the TF arguments twice, nor does the quark test 
manually, but perhaps there are stylistic objections to it.

Lars Hellström