Method Calls

 

  method_call ::=  designator [`!'] [ '(' arguments ')' ] .
  arguments ::= argument ( ',' argument )\stern .
  argument ::=  general_expression  |  '\&' designator |  '\&\&' designator .

Example: max(a,b); i1.divmod(i2,& div, & mod); obj.attr.elts!; o.f(,,);

Direct stream calls and calls of a stream are distinguished by the symbol ! after its identifier.

Methods whose bodies are external belong to an external class. The body can indicate what name the compiler is to use to refer to the appropriate extternal procedure. If the name is not explicitly given (by a string constant), the name of the procedure will be used cf. 9.1.2.

Method calls can be object calls a.m or class calls C::m. If the type of a is a polymorphic type $C (polymorphic method call) then the declaration of m in class is used for checking the validity of the call and for inferring the type of arguments and the result.

A method call carries as its 0-th argument the reference to its object. In the method body this argument has the name self of type C. When the method is called by without reference to an object then the value of self is void. self is a constant local entity of the method.

A method call is valid only

• if the number of arguments and the number of parameters in the declaration of the method are the same, and
• if the types of all the in- and once-arguments conform to the types given in the declaration of the method, and
• if for all out-parameters the types given in the declaration of the method conform to the actual out-arguments, and
• if for all inout-parameters the types given in the declaration of the method and the types of the actual inout-arguments are the same, and
• if all out- and inout-arguments are entities to which assignments are allowed in the context of the method call.

• Procedure Calls
• Stream Objects, Stream Calls and the Resume Statement