The connection operator

 

ConnectionExpression ::= 
    Expression "." Identifier Actuals
Actuals ::= 
    "(" Expressions ")" |
    <void>

The Expressions grammar rule is defined in the section about expressions.

The connection operator is used to use (or call) a feature of a non-terminal or of an environment, or refer to an annotation attached to a non-terminal. For instance, in:

OUT.WriteLn ("Hello world");

OUT

is an instance of the environment responsible for input/output, on which one calls the WriteLn feature, providing a single character string argument ``Hello world''.

The connection operator can be used as a left-value for an assignment in case of an annotation only. The predefined features of the various non-terminal classes are read-only.