
# This has all not yet been implemented.
#
#
# d::DifferentialD({x,y,z},dimension=3).
# 
# A:= f(x) d[y];
# d[@(A)];
# 
# A(phi) d[phi] ^ B(psi) d[psi];
# 
# d[ @(%) ];

# \diff{f(x)}{x};
#
# f::Depends(x).
# \diff{f}{x};
