Getting more comfortable with nesting things:

#1:
local in=($1,*(N))
#2:
local sorted=$(print -l "${(n)in[@]}")
#3:
sorted=( "${(f)sorted}" )

     ... works fine, now I do an  exact verbatim nesting of line two 
into line three:

local sorted=( "${(f)$(print -l "${(n)in[@]}") }" )

     "bad substitution".  Ok, that could be because we can't nest quotes so:

local sorted=( "${(f)$(print -l "${(n)in[@]}") }" )
local sorted=( "${(f)$(print -l \"${(n)in[@]}\") }" )
local sorted=( "${(f)$(print -l ${(n)in[@]}) }" )
local sorted=( ${(f)$(print -l ${(n)in[@]}) } )

     .... none of those work.  Is this something were a literal 
substitution of one block of characters can't work?  It hardly matters 
in practice, I prefer the three steps above, it's easier to digest, but 
purely as a theoretical question, can I nest line two and three, or even 
all three lines?  I'd like to understand why the parser doesn't like my 
efforts.  I can see that the 'no nested quotes' rule could make some 
literal substitutions logically impossible. But maybe there is a way.  
If so, seeing how will be instructive.