It actually is possible to do what you want, but only if you use the functional form of the indexing operator. When you perform an indexing operation using (), you are actually making a call to the SUBSREF function. So, even though you can't do this:
value = magic(5)(3,3);You can do this:
value = subsref(magic(5),struct('type','()','subs',{{3,3}}));Ugly, but possible, ;)
In general, you just have to change the indexing step to a function call so you don't have two sets of parentheses immediately following one another. Another way to do this would be to define your own anonymous function to do the subscripted indexing:
subindex =@(A,r,c) A(r,c);%#An anonymous function to index a matrix
value = subindex(magic(5),3,3);%#Use the function to index the matrix