VDM-10 Language Manual

Chapter 12
Operation Definitions
Operations have already been mentioned in section 4. The general form is described here and
for VDM++ and VDM-RT special operations called constructors which are used for constructing
instances of a class are described in section 12.1. Note that the async keyword can only be used
in the VDM-RT dialect.
Syntax: operation definitions = ‘operations’, [ access operation definition ],
{ ‘;’, access operation definition } ;
, [ ‘;’ ]
access operation definition = ( [ ‘async’ ] [ access ], [ ‘static’ ])
| ( [ ‘async’ ] [ ‘static’ ], [ access ]),
operation definition ;
operation definition = explicit operation definition
| implicit operation definition
| extended explicit operation definition ;
explicit operation definition =
implicit operation definition =
identifier, ‘:’, operation type,
identifier, parameters,
‘==’,
operation body,
[ ‘pre’, expression ],
[ ‘post’, expression ] ;
identifier, parameter types,
[ identifier type pair list ],
implicit operation body ;
implicit operation body = [ externals ],
[ ‘pre’, expression ],
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