6.7 Null Procedures
1/2
A null_procedure_declaration
provides a shorthand to declare a procedure with an empty body.
Syntax
2/2
null_procedure_declaration ::=
[
overriding_indicator]
procedure_specification is null;
Static Semantics
3/2
A
null_procedure_declaration
declares a
null procedure.
A completion is not allowed for a
null_procedure_declaration.
Dynamic Semantics
4/2
The execution of a null procedure is invoked by a
subprogram call. For the execution of a subprogram call on a null procedure,
the execution of the subprogram_body has no
effect.
5/2
The elaboration of a
null_procedure_declaration
has no effect.
Examples
6/2
procedure Simplify(Expr :
in out Expression)
is null; --
see 3.9
--
By default, Simplify does nothing, but it may be overridden in extensions of Expression
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