Question: subroutine calling

Hi,

I am new to Maple and I am trying to write a CFD code. I want my code to be as modular as possible, therefore, I want to use subroutines  in my code. (Because I will need to do some steps several times )

Here is one of the main subroutines that I want to call for it in various times with different parameters. I am familiar with matlab so let be show what I mean first in matlab notation.   Lets say my subroutine is called MAT 

inside the main code when I call for MAT ==> [Dx,D2x,x]=MAT(Lx,GL)

inside the MAT subroutine                     ==>  [D,D2,z]=MAT(N,T)

So MAT takes L and GL    and gives back Dx D2x and x. And MAT knows that Dx corresponds to D 

                                                                                                           D2x corresponds to D2

                                                                                                            x   corresponds to z

So I can use MAT several times with different variable names, i.e.,

[Dx,D2x,x]=MAT(Lx,GL)

[Dz,D2z,z]=MAT(Lz,T)

How can I do the same thing in MAPLE?  calling my subroutine, defining input and output variables.  

Thank you for the help.

Erdem