1.127 class program_object

Class program_object is the super-class of all classes that form PCE's "program world": classes, methods, variables, types and executable objects representing statements (class code).

This class defines the tracing capabilities of PCE using the methods:

• program_object->trace Set a (conditional) trace-point on this object. Entry and exit to this executable object will be printed.
• program_object->break Set a (conditional) break-point on this object. The interactive tracer will be trapped when the object is executed.

1.127.1 Instance variables

program_object <-> dflags: int

The various debugging options are represented by an inclusive or of bit-masks. The only legal user operation on these flags is:

get(ProgramObject, dflags, Flags),
<various trace/break operations>
send(ProgramObject, dflags, Flags).

1.127.2 Send methods

program_object ->break: ports=[{full,enter,exit,fail}], value=[bool]

A break-point is similar to a trace-point (see program_object->trace). After printing the entry or completion of the execution of an object it prompts the user how to continue.

At this prompt, the user may examine various stacks, set new trace or break-points, etc.

See also

program_object->trace

program_object ->initialise:

Initialises -dflags to represent program_object->trace: @default and program_object->break: @default (i.e. inherit the value). If the program_object is created by a goal running in system mode, the program_object<-system flag is set to @on.

program_object ->initialise_new_slot: variable

Initialises -dflags when loading program objects created before the introduction of this class. See source_sink<-object.

program_object ->system: bool

When @on, the execution of the object is performed in system-mode, which implies that trace- and break-points reached during the execution will only be printed if pce<-trace equals always.

program_object ->trace: ports=[{full,enter,exit,fail}], value=[bool]

Set/clear a trace-point on the indicated object. If an object that has a trace-point set is executed a message will be printed on entry and/or exit.

The arguments are:

on/off / inherit

if @on, a trace-point is set on this object. If @off, this object is not traced. If @default, the value if the trace point is inherited. For normal objects the trace-flags will be inherited from the class. For classes it will be inherited from the super-class.

port(s)

The following ports or combinations of ports are defined:

full	Trace all ports (enter, exit and fail)
enter	Only trace entry
exit	Only trace successful completion
fail	Only trace completion with failure

Condition

When present, this code object will be executed if the other conditions are met. If this code object returns success the trace-point will be printed. The arguments are:

@receiver	Receiver of the action
@selector	Selector of the action
@arg1 ...	The arguments.

See also

program_object->break

1.127.3 Get methods

program_object <-break: port=[{enter,exit,fail}] -> bool

Inherits description from: program_object->break

program_object <-system: -> bool

Inherits description from: program_object->system

program_object <-trace: port=[{enter,exit,fail}] -> bool

Inherits description from: program_object->trace