// Declarations
// The tag values
<int tagvalue>;

// The return values
[unsigned threadid <int>];
[unsigned hostid <int>];

// Step prescription 
<tagvalue> ::  (compute);

// Step execution
(compute) -> [threadid];
(compute) -> [hostid];

// Input from the environment: initialize all tags
env -> <tagvalue>; 

// Output to the environment is the collection of fvalues
[threadid] -> env;
[hostid] -> env;
<tagvalue> -> env;