VDM-10 Language Manual

VDM-10 Language Manual
Examples: Given the following sequences:
✞
✡✝
secondRoundWinners = [,,,,,,,];
secondRoundRunnersUp = [,,,,,,,]
✆
The operation SecondRound, in VDM++ from class GroupPhase returns the sequence
of pairs representing the second round games gives an example of a def statement:
✞
SecondRound : () ==> seq of (Team * Team)
SecondRound () ==
def winners = { gp |-> GroupWinner(gp)
| gp in set dom gps };
runners_up = { gp |-> GroupRunnerUp(gp)
| gp in set dom gps}
in
return ([mk_(winners(secondRoundWinners(i)),
runners_up(secondRoundRunnersUp(i)))
| i in set {1,...,8}])
✡✝
✆
13.3 The Block Statement
Syntax: statement = . . .
| block statement
| . . . ;
block statement = ‘(’, { dcl statement },
statement, { ‘;’, statement }, [ ‘;’ ], ‘)’ ;
dcl statement = ‘dcl’, assignment definition,
{ ‘,’, assignment definition }, ‘;’ ;
assignment definition = identifier, ‘:’, type, [ ‘:=’, expression ] ;
Semantics: The block statement corresponds to block statements from traditional high-level programming
languages. It enables the use of locally defined variables (by means of the declare
statement) which can be modified inside the body of the block statement. It simply denotes
the ordered execution of what the individual statements prescribe. The first statement in the
sequence that returns a value causes the evaluation of the sequence statement to terminate.
This value is returned as the value of the block statement. If none of the statements in the
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