"xyz" =~ /\w*?/g;

##</code><code>##

s/(\w*?)/($1)/g

##</code><code>##

()(x)()(y)()(z)()

##</code><code>##

:s/\v(.{-0,})/(\1)/g

##</code><code>##

()x()y()z

##</code><code>##

()x()y()z()

##</code><code>##

begin(N) <= end(N) <= begin(N+1) <= end(N+1)
begin(N) < begin(N+1)
end(N) < end(N+1)

##</code><code>##

A ()xyz   # Return it
b (x)yz   # Fails: 0==begin(A) < begin(b)==0
c (xy)z   # Fails: 0==begin(A) < begin(c)==0
d (xyz)   # Fails: 0==begin(A) < begin(d)==0
E x()yz   # Return it
f x(y)z   # Fails: 1==begin(E) < begin(f)==1
g x(yz)   # Fails: 1==begin(E) < begin(g)==1
H xy()z   # Return it
i xy(z)   # Fails: 2==begin(H) < begin(i)==2
J xyz()   # Return it

##</code><code>##

A ()xyz   # Return it
B (x)yz   # Return it
c (xy)z   # Fails: 1==end(B) <= begin(c)==0
d (xyz)   # Fails: 1==end(B) <= begin(d)==0
E x()yz   # Return it
F x(y)z   # Return it
g x(yz)   # Fails: 2==end(F) <= begin(g)==1
H xy()z   # Return it
I xy(z)   # Return it
J xyz()   # Return it

##</code><code>##

(x)()y()z()

##</code><code>##

:s/\vx{-0,}(x)@!/(\1)/g
(x)y()z

##</code><code>##

(x)y()z()