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Reporting

rascal-0.34.0
typepal-0.8.10

Synopsis​

How to format and report errors, warnings and info messages.

Description​

Reporting may be done both in the Collector and the Solver. It uses values of the datatype FailMessage that can be created as follows:

FailMessage error(value src, str msg, value args...);
FailMessage warning(value src, str msg, value args...);
FailMessage info(value src, str msg, value args...);

Here,

  • src is a Tree or loc that is the subject of the report.
  • msg is an informative string to be printed. It may contain insertion directives.
  • args are zero or more values to be inserted in the insertion directives in msg.

The following insertion directives are supported:

  • %t: insert the type of the next element of args.
  • %v: insert the value of the next element of args.
  • %q: quote and insert the type or value of the next element of args.
  • %%: insert the character %.