VDM-10 Language Manual

Chapter 14. Top-level Specification (VDM++ and VDM-RT)
min_index : seq1 of nat -> nat
min_index(l) ==
if len l = 1
then 1
else let mi = min_index(tl l)
in
if l(mi+1) < hd l
then mi+1
else 1
operations
sort_ascending : () ==> ()
sort_ascending () == selectSort(1);
selectSort : nat ==> ()
selectSort (i) ==
if i < len data
then (dcl temp: nat;
dcl mi: nat := min_index(data(i,...,len data)) +
i - 1;
temp := data(mi);
data(mi) := data(i);
data(i) := temp;
selectSort(i+1)
)
end SelectionSort
✡✝
✆
Here the class Sort defines an abstract interface to be implemented by different sorting
algorithms. One implementation is provided by the SelectionSort class.
The next example clarifies how name space clashes are resolved.
✞
class A
instance variables}
i: int := 1;
j: int := 2;
end A
class B is subclass of A
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