# Composite function

If I define:

var('x,y,z,t')

g(t) = (t, t^2, t^3)

f(x,y,z) = (2*x,y+x+z,y*x)

Is there a way for me to define the composite f(g(t)) without going through:

f(g(t)[0],g(t)[1],g(t)[2])

or something equally ugly?