Component description file

This chapter describes the syntax of the genom component description file. This file has by convention a name ending with the .gen suffix. It is thus often called the .gen file (or dot gen).

The dot gen file contains the complete formal description of a component in terms of services and data types it provides. Such a description completely defines the interface and the internals of a component. The syntax of this files is a mix between a subset of the OMG IDL for data types definitions and genom specific constructs.

The dot gen file is pre-processed by a pre-processor that follows the standard of the C preprocessor. See the Preprocessing section for details. The complete grammar definition is available for reference, but the most important constructs are detailed in the following sections.

The description of the dot gen grammar uses a syntax notation that is similar to EBNF (Extended Backus-Naur Format). The following table lists the symbols used in this format and their meaning.

Table 1. dotgen 'EBNF' symbols
Symbol Meaning






Non terminals



( …​ )


{ …​ }

Repetitions: may occur zero or any number of times

[ …​ ]

Option: may occur zero or one time