# Composite Functions Necessary to List All Variables

For composite functions (in this case q), is it necessary to list all the variables of the inner functions? For example, in the line below Column[, cant we just write q[z], or must we write q[z[x,y[x]]? Wouldn't it be really troublesome if our composite function has many layers?

y[x_] := x^2;
z[x_, y_] := y - x;
q[z_] := z^2;

Manipulate[
{
Column[
{x, y[x], z[x, y[x]], q[z]}
]
},
{x, 1, 2}
]

• Could use a With[]: With[{zz = z[x, y [x]]}, {zz, q[zz]}] – J. M. is away Sep 27 '17 at 15:47

ClearAll[x, y, z, q]