LLOOP References

The ERTMS Operational Simulator is a very successful product of the company ERSA which allows to simulate the driving of a train on a ETCS-fitted line (ETCS - European Train Control System, a subset of ERTMS, the European Rail Traffic Management System). The simulator comprises a true DMI application (driver machine interface), accurate and comprehensive trainborne and track simulation systems, and a real-world 3D view.

This simulator is widely used in many European countries, either by industrials, railway authorities, private consortiums or European Institutes.

To make simulations as close as possible to real-life situations, the simulator relies on scenario files which feature a rich set of parameters and commands, like train dynamics simulation parameters, trainborne parameters, track parameters and so forth.

For managing these scenario files, LLOOP has been preferred to other solutions like manual coding or using generic parsers (eg. XML) for the following reason:

For the user:
• Scenario files can be designed in a way they are readable and convenient to write for the final user.
• Parameters and commands can be structured and designed in a way which is consistent and easy to understand for a human operator.
• Errors are reported accurately to the user of the simulator. It helps him greatly in finding the syntax error or the invalid value specified for an expected type of input data, depending on context and meaning of parsed data.
For the developer:
• It allows to keep manual coding at a minimum. The parser checks automatically the syntax of the custom file format as well as the type and range of parameter values.
• It allows to integrate the parsed data to the overall application very efficiently. The structure of objects needed on application-level for running the simulation is set-up automatically during parsing.
• It dramatically eases extensions and maintenance. Only a few minutes are required to add new parameters and integrate them at application-level. Likewise, supporting synonyms or alternative writings for specifying parameters is extremely simplified.

The Industrial ERTMS DMI developed by the company ERSA is an embedded man-machine display device intended for driving ETCS trains (ETCS - the European Train Control System). The ERTMS DMI has safety implications for ETCS-fitted trains and lines, and therefore has to be developed and certified according to the European Standards in force currently.

ERSA is being increasingly asked by the international industry as supplier for its Industrial ERTMS DMI. More than hundred units have been supplied and are operating in laboratories or in field.

The ERTMS DMI is a highly flexible product which allows, through XML configuration files, to customise data entry, ergonomics and communication interfaces to the country and customer.

For managing these XML configuration files, LLOOP has been preferred to a generic XML parser for the following reason:

For the user:
• Errors are reported accurately to the operator and helps him greatly in finding the syntax error or the invalid value specified for an expected type of input data.
• It eases a lot the development of a custom built-in error management which relies on context, content and meaning of parsed data.
For the developer:
• The parser allows to check the type, range and consistency of values given for parameters depending on context and meaning of parsed data.
• It allows to get the configured application objects needed on application level from the parsed data (direct application-level integration) without requiring additional code to convert one data structure to another.
• It dramatically eases extensions and maintenance. Only a few minutes are required to understand existing specifications, add new parameters and integrate them at application-level.
• The overload is negligible for writing syntax rules in BNF instead of specifying the XML file syntax in DTD.

Makedoc is a GUI-based HTML documentation generator for C, C++, and Qt-enhanced C++, which focus on simplicity of use and source code independence.

The generator engine which analyses C and C++ code relies on a LLOOP parser.

The implementation of Makedoc's command line option was also entirely built upon the advanced features provided by LLOOP for managing command line options, inclusive all entry forms.

Makedoc's Graphical Front End is built upon the generic GFE application and forms generated from the command line option specification.

This all makes Makedoc a suitable application for validating most of LLOOP's features.

LLOOP (GFE LLOOP and gspc) is of course also built upon code generated by itself. It is used for parsing the .gsp spec files and controlling all generator options either by command line or graphical interface.