Decoupling the concept of a Functional and that of a Form

[Martin Sandve Alnæs]

I'm considering an idea for the decoupling of a 'functional' concept from the 'form' concept. Basically, a Functional is a sum of integrals of expressions depending on functions, while a Form is a Functional with a tuple of coefficients associated as form arguments.

u = Coefficient(V)
v = Coefficient(V)
f = Coefficient(V)
M = dot(grad(u),grad(v))*dx(1) + f*v*ds # a Functional
a = M(u,v) # a Form
astar = M(v,u) # another Form referencing the same Functional

There are probably some things to work out for this idea to be most useful, but I just wanted to throw it out there. Please provide examples for potential uses for this feature. It is mainly in the higher level algorithms working with forms and functionals I see this as potentially useful.