1.54.1 Instance variables

error <-> feedback: {report,throw,print,backtrace}

Determines how the error is reported (provided it is reported; see error<-kind). Its values are:

report

Invokes object->report to report the error. See also visual->report.

throw

If the error is raised in a context called by the host-language, and the host-language indicates it wants to handle the error itself, the error is recorded in the hosts goal-frame and the object->error succeeds with failure. When control is returned to the host-language, the host-language should raise and error (For example, as throw/1 in Prolog):

?- catch(send(@pce, hello), E, true).

E = error(pce(@290191/error,
                      [@pce/pce, (->), hello]),
                  send(@pce/pce, hello))

print

Prints the error in the window from which xpce was started.

See also

error-kind

error <- format: string

Format string used to print the message. Used by error->display. See string->format for a description of the format arguments. The first argument formatted is always the generator of the error (the object receiving object->error). The remaining arguments are the context arguments from object->error.

error <- id: name

Unique identifier of the error. The hash_table @errors maps error identifiers to error objects. See also error<-convert and error<-lookup.

error <-> kind: {status,inform,warning,error,fatal,ignored}

Describes how serious the error is. The error categories are related to the report categories defined by object->report (see visual ->report'), except for fatal and ignored`.

The values are:

status

Provide status information that may be ignored by the user.

inform

Provide status information that may not be ignored by the user.

warning

Report a problem that may be ignored by the user.

error

Report a problem that may not be ignored by the user.

fatal

A message is printed and the stacks are dumped. After this, PCE attempts to return to the host (Prolog, Lisp) toplevel.

ignored

The invoked action fails silently.

See also

error-feedback