ProblemType

The corresponding Problem is not actually an unexpected condition, but it may still be useful to report the information to the user. It's unclear whether this will actually be used for anything other than debugging the compiler.

The corresponding Problem indicates a situation that is less than ideal. A ProblemHandler may choose to present this warning, and then continue compilation.

A Problem occurred while tracing a module's dependencies. This condition only indicates a narrow range of problems, such as unresolved or recursive dependencies. Syntax errors in the module header that preclude a correct trace are treated as PARSE problems.

A Problem occurred while parsing a module's body. This includes both malformed tokens and assemblies of tokens that could not be successfully transformed into phrases.

A Problem occurred while executing Avail code. Typically this means an unhandled exception, or invoking a bootstrap primitive before the relevant exception handling mechanisms are in place. This should be treated as a fatal problem.

An internal Problem occurred in the virtual machine. This should not happen, and is not the fault of the Avail code, but rather Yours Truly, the Avail virtual machine authors.

An external Problem occurred. This indicates a failure in something outside the control of the virtual machine, for example a disk read failure.