VDM-10 Language Manual

Chapter 6. Expressions
mu operator. The set of teams is then updated with the new scores replacing the original
ones.
✞
✡✝
win : Team * Team * set of Score -> set of Score
win (wt,lt,gp) ==
let wsc = iota sc in set gp & sc.team = wt,
lsc = iota sc in set gp & sc.team = lt
in
let new_wsc = mu (wsc, won |-> wsc.won + 1,
points |-> wsc.points + 3),
new_lsc = mu (lsc, lost |-> lsc.lost + 1)
in
(gp \ {wsc,lsc}) union {new_wsc, new_lsc}
pre forall sc1, sc2 in set gp &
sc1 sc2 sc1.team sc2.team
and {wt,lt} subset {sc.team | sc in set gp}
✆
6.12 Apply Expressions
Syntax: expression = . . .
| apply
| field select
| tuple select
| function type instantiation
| . . . ;
apply = expression, ‘(’, [ expression list ], ‘)’ ;
field select = expression, ‘.’, identifier ;
tuple select = expression, ‘.#’, numeral ;
function type instantiation = name, ‘[’, type, { ‘,’, type }, ‘]’ ;
Semantics: The field select expression can be used for records and it has already been explained
in section 3.2.5 so no further explanation will be given here.
The apply is used for looking up in a map, indexing in a sequence, and finally for calling
a function. In section 3.2.3 it has already been shown what it means to look up in a map.
Similarly in section 3.2.2 it is illustrated how indexing in a sequence is performed.
In the VDM languages an operation can also be called here. This is not allowed in standard
VDM-SL and because this kind of operation call can modify the state such usage should
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