VDM-10 Language Manual

Appendix A. The Syntax of the VDM Languages
In VDM-SL extended explicit function definition looks like:
extended explicit function definition = identifier, [ type variable list ],
parameter types,
identifier type pair list,
‘==’, function body,
[ ‘pre’, expression ],
[ ‘post’, expression ] ;
In VDM++ and VDM-RT extended explicit function definition looks like:
extended explicit function definition = identifier, [ type variable list ],
parameter types,
identifier type pair list,
‘==’, function body,
[ ‘pre’, expression ],
[ ‘post’, expression ] ;
type variable list = ‘[’, type variable identifier,
{ ‘,’, type variable identifier }, ‘]’ ;
identifier type pair = identifier, ‘:’, type ;
parameter types = ‘(’, [ pattern type pair list ], ‘)’ ;
identifier type pair list = identifier, ‘:’, type,
{ ‘,’, identifier, ‘:’, type } ;
pattern type pair list = pattern list, ‘:’, type,
{ ‘,’, pattern list,‘:’, type } ;
parameters list = parameters, { parameters } ;
parameters = ‘(’, [ pattern list ], ‘)’ ;
function body = expression
| ‘is not yet specified’
| ‘is subclass responsibility’ ‘is not yet specified’ ;
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