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Ulm's Oberon Library:
CompilerErrors

NAME

SYNOPSIS

TYPE ErrorEvent = POINTER TO ErrorEventRec;
TYPE ErrorEventRec =
   RECORD
      (Events.EventRec)
      loc1, loc2, reference: CompilerObjects.Location;
      longmsg: Streams.Stream;
   END;
VAR error: Events.EventType;



PROCEDURE Raise(errors: RelatedEvents.Object;
                at: CompilerObjects.Location;
                message: ARRAY OF CHAR);



PROCEDURE Open(VAR s: Streams.Stream);
PROCEDURE At1(s: Streams.Stream; location: CompilerObjects.Location);
PROCEDURE At2(s: Streams.Stream; location: CompilerObjects.Location);
PROCEDURE Ref(s: Streams.Stream; location: CompilerObjects.Location);
PROCEDURE AtObject1(s: Streams.Stream; object: CompilerObjects.Object);
PROCEDURE AtObject2(s: Streams.Stream; object: CompilerObjects.Object);
PROCEDURE RefObject(s: Streams.Stream; object: CompilerObjects.Object);
PROCEDURE Close(s: Streams.Stream; errors: RelatedEvents.Object);



PROCEDURE GetSortedErrors(errors: RelatedEvents.Object;
                          VAR it: Iterators.Iterator);

DESCRIPTION

As all error events generated by CompilerErrors are passed to RelatedEvents, an error object is needed that collects all error events, i.e. RelatedEvents.QueueEvents must be called for it. This object may be an otherwise empty object or any other extension of RelatedEvents.Object that is permitted to receive other error events as well.

Error events are created in a short and simple way by Raise, or, in case of more elaborate messages, by Open, various location referencing procedures, and Close. Finally, GetSortedErrors may be called to extract all compilation error events from errors (but leaving all other events), sorted by their primary location.

All error events generated by CompilerErrors have following components:

type

Shared event type that is always set to CompilerErrors.error.

message

Abbreviated error message of type Events.Message.

loc1

Primary location, always non-NIL. Used as key by GetSortedErrors.

loc2

Is set if two items belong to this error event. May be NIL. loc2 is expected to be close to loc1 and must belong to the same source. Example: Two expressions combined by an operator that are not compatible to each other.

reference

A more distant location that is given as reference. It may even belong to another source as loc1. May be NIL. Example: First declaration in case of multiple declarations.

longmsg

Non-abbreviated error message.

Raise creates a simple error event referencing just one location and giving a message.

Open creates a stream where the error message may be written to and which, in addition, supports following operations: At1, At2, and Ref set the primary, secondary, and reference location, respectively. AtObject1, AtObject2, and RefObject work similarly but take the location from object.loc instead. Note that either At1 or AtObject1 must be called. If the error message has been printed to s and all locations are defined, Close generates the error event and relates it to errors.

GetSortedErrors removes all error events that are extensions of CompilerErrors.ErrorEvent from errors and returns them in sorted order (by their primary location) through it.

DIAGNOSTICS

• multiple definitions of a location,
• missing source references or source headers in locations,
• overlapping locations,
• empty error messages,
• missing definition of the primary location, and
• foreign streams that are passed to At1 and all other location-defining operations.

SEE ALSO

CompilerObjects

base type of locations

Listers

general interface for error listers

RelatedEvents

object-oriented event handling

BUGS

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