Domain-specific error messages

The textX system raises Python errors that are helpful for DSL developers but will not always be clear to DSL users. Therefore, a module must be provided that builds upon Python exceptions and warnings and produces messages that are easily understandable only with domain-specific knowledge. Typical candidates are: TextXSyntaxError, TextXSemanticError, ExpressionTypeError, TypeMismatchError etc.

Additionally, standard outputs should be also made domain specific. Additionally, all this can be organized using a logger and different log levels, such as error, warning, info, and debug.

As start these errors can be processed:

• incomplete input data due to non-resolved references
• race conditions

Because references are resolved by the parser (otherwise TextXSemanticError). Race conditions are also not possible because again if a reference cannot be set to a non-unique object (also TextXSemanticError). These errors must be caught and processed in the model instantiation call.