VDM-10 Language Manual

Appendix A. The Syntax of the VDM Languages
A.7.18
The Is Expression
general is expression = is expression
| type judgement ;
is expression = ‘is ’, 2 name, ‘(’, expression, ‘)’
| is basic type, ‘(’, expression, ‘)’ ;
type judgement = ‘is ’, ‘(’, expression, ‘,’, type, ‘)’ ;
A.7.19
The Undefined Expression
undefined expression = ‘undefined’ ;
A.7.20
The Precondition Expression
pre-condition expression = ‘pre ’, ‘(’, expression,
[ { ‘,’, expression } ], ‘)’ ;
A.7.21
Base Class Membership (VDM++ and VDM-RT)
isofbaseclass expression = ‘isofbaseclass’, ‘(’, name, expression, ‘)’ ;
A.7.22
Class Membership (VDM++ and VDM-RT)
isofclass expression = ‘isofclass’, ‘(’, name, expression, ‘)’ ;
A.7.23
Same Base Class Membership (VDM++ and VDM-RT)
samebaseclass expression = ‘samebaseclass’, ‘(’, expression,
expression, ‘)’ ;
A.7.24
Same Class Membership (VDM++ and VDM-RT)
sameclass expression = ‘sameclass’, ‘(’, expression,
expression, ‘)’ ;
2 Note: no delimiter is allowed
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