Section: Flow Control
return statement is used to immediately return from
a function, or to return from a keyboard session.  The 
syntax for its use is
return
Inside a function, a return statement causes FreeMat
to exit the function immediately.  When a keyboard session
is active, the return statement causes execution to
resume where the keyboard session started.
return to exit the function if a certain test condition 
is satisfied.
     return_func.m
function ret = return_func(a,b)
  ret = 'a is greater';
  if (a > b)
    return;
  end
  ret = 'b is greater';
  printf('finishing up...\n');
Next we exercise the function with a few simple test cases:
--> return_func(1,3) finishing up... ans = b is greater --> return_func(5,2) ans = a is greater
In the second example, we take the function and rewrite
it to use a keyboard statement inside the if statement.
     return_func2.m
function ret = return_func2(a,b)
  if (a > b)
     ret = 'a is greater';
     keyboard;
  else
     ret = 'b is greater';
  end
  printf('finishing up...\n');
Now, we call the function with a larger first argument, which
triggers the keyboard session.  After verifying a few
values inside the keyboard session, we issue a return
statement to resume execution.
--> return_func2(2,4) finishing up... ans = b is greater --> return_func2(5,1) [return_func2,4]--> ret ans = a is greater [return_func2,4]--> a ans = 5 [return_func2,4]--> b ans = 1 [return_func2,4]--> return finishing up... ans = a is greater