VDM-10 Language Manual

VDM-10 Language Manual
Examples: The operation Remove demonstrates the use of a sequence-for loop to remove all
occurences of a given number from a sequence of numbers:
✞
✡✝
Remove : (seq of nat) * nat ==> seq of nat
Remove (k,z) ==
(dcl nk : seq of nat := [];
for elem in k do
if elem z
then nk := nkˆ[elem];
return nk
);
✆
A set-for loop can be exploited to return the set of winners of all groups:
✞
✡✝
GroupWinners: () ==> set of Team
GroupWinners () ==
(dcl winners : set of Team := {};
for all gp in set dom gps do
(dcl winner: Team := GroupWinner(gp);
winners := winners union {winner}
);
return winners
);
✆
An example of a index-for loop is the classic bubblesort algorithm:
✞
✡✝
BubbleSort : seq of nat ==> seq of nat
BubbleSort (k) ==
(dcl sorted_list : seq of nat := k;
for i = len k to 1 by -1 do
for j = 1 to i-1 do
if sorted_list(j) > sorted_list(j+1)
then (dcl temp:nat := sorted_list(j);
sorted_list(j) := sorted_list(j+1);
sorted_list(j+1) := temp
);
return sorted_list
)
✆
108