Will Robertson wrote:
 >> Should~be~F:~\token_if_expandable:NTF \the {T} {F} \\
> 
> So here, while \the isn't a macro, it will expand when used correctly in
> an edef (e.g., \edef\foo{\the\baselineskip} ).  I've explicitly caught
> undefined macros to return "F" because it just seemed more logical that
> way.

[snip]

> 3.  Can we think of a less confusing name for it?
>     Maybe  \token_if_will_expand  ?
>     Unless it's only me that finds "\token_if_expandable" confusing.

But if I try to do a single expansion (rather than an \edef), I'll get
an infinite loop with something like \the.  So I'm not sure
"if_will_expand" is really accurate.

Joseph