Sorting Machine Template

Concept Sorting_Machine_Template (type entry; max)capacity: integer; ordering £ );

uses integer, boolean, ordering theory;

Family entry_keeper Í cartesian product

entry_count: (entry ® N);

dispensing: B;

exemplar K;

definition Total_Entry_Ct (k:entry_keeper): N = ();

constraint Total_Entry_Ct £ max_capacity;

initialization

ensures k.dispensing = false and Total_Entry_Ct = 0;

definition Is_Only_Addition (x: entry; k1, k2: entry_keeper): B =

operation add_entry (var x: entry; var k: entry_keeper);

requires Total_Entry_Ct < max_capacity and k.dispensing = false;

ensures Is_Only_Addition(x,@k,k) and k.dispensing = false;

operation prepare_to_dispense (var k: entry_keeper);

requires k.dispensing = false;

ensures k.dispensing - true and k.entry_count = @k.entry_count;

operation get_a_smallest (var s: entry; var k: entry_keeper);

requires k.dispensing = true and Total_Entry_Ct > 0;

ensures k.dispensing = true and Is_Only_Addition(s, k, @k) and " x, if x < s, @k.entry_count = 0;

operation Total_Entry_Count (k: entry_keeper): integer;

ensures Total_Entry_Count = Total_Entry_Ct(k);

operation is_dispensing (k: entry_keeper): boolean;

ensures is_dispensing = k.dispensing;

operation clear(var k: entry_keeper);

ensures k.dispensing = false and Total_Entry_Ct = 0;

end;