how can I create a reference to a variable in specman?

Question

I have the following code in specman:

var x := some.very.long.path.to.a.variable.in.another.struct;

while (x == some_value) {
    //do something that uses x;
    //wait for something

    //get a new value for x
    x = some.very.long.path.to.a.variable.in.another.struct;
};

Now, it seems wasteful to write the assignment to x twice; once during initialization and once during the loop.

What I really want to use is a reference to the long variable name, so that I could do:

var x := reference to some.very.long.path.to.a.variable.in.another.struct;

while (x == some_value) {
    //do something that uses x;
    //wait for something
    //no need to update x now since it's a reference
};

Can this be done in specman?

Answer 1

Hi Nathan,

specman/e generally uses references for structs and lists, so if your variable type is either of it your second example should work. For integer or boolean I don't know a way to use a reference for a variable. Anyway, two ideas which might help you:

1. Add a pointer to the other struct and bind it in a config file:

   struct a { other_variable : uint; };
   struct b {
       other_struct : a;
       some_func() is {
           var x : uint = other_struct.other_variable;
           while (x == some_value) {
               x = other_struct.other_variable;
           };
       };
   };
   extend cfg {
       struct_a : a;
       struct_b : b;
       keep struct_b.other_struct == struct_a;
   };
   

   UPDATE: You can find some more information on this technique in this Team Specman Post.

2. Wrap your while loop in a function, there you can pass parameters by reference (see help pass reference):

       some_func(x : *uint) is {
           while (x == some_value) {
               // stuff ...
           };
       };
   

Hope this helps!

Daniel