You can store your own operations in macros. See Macros in the Programming Methods. Similarly, you can create custom matrix functions. For example, you can make your own matrix operation called Mag() to find the magnitude of a vector, as follows:
mag = Function( {x},
Sqrt( x` * x )
);
Similarly, you could create a function called Normalize to divide a vector by its magnitude, as follows:
normalize = Function( {x},
x / Sqrt( x` * x )
);