In [1]: using SIUnits
type a; x; end
*(A::a, c::Real)=A.x*c
A=a(1)
A*1Meter*Second
Out[1]: no method *(a, SIQuantity{Int64,1,0,0,0,0,0,0})
while loading In[3], in expression starting on line 1
in * at operators.jl:82
In[2]: A*1*Meter*Second
Out[2]: 1 m s