HELP FTRACE_MESSAGE                       Mark Rubinstein  December 1985
                                            Revised A.Schoter  June 1991

This help file describes the flavours tracing mechanism as defined
in the file LIB * FTRACE_MESSAGE (see TEACH * FLAVOURS for full details
of the Flavours object oriented package).  This library is autoloaded
whenever you try and send the message "ftrace" to a flavour (see HELP *
DEFAULT_METHOD).

To trace a method you need to send a message to the appropriate instance
of the flavour (see REF * METAFLAVOUR_FLAVOUR). The methods provided for
tracing are as follows:

    FTRACE - takes either a word, the name of a method, or a list of names
        of methods to trace.
    FTRACEALL - switches on tracing for all the methods for the given
        flavour.
    UNFTRACE - as with FTRACE, switches off the tracing of methods.
    UNFTRACEALL - untraces all traced methods.

For example, given that person_flavour has been defined as in TEACH *
FLAVOURS, the follow would be possible:

    person_flavour <- ftrace("marry");
    charles <- marry(diana);
    >Charles<-marry Diana
    ** [I Charles take Diana to be my lawfully wedded other]
    !>Diana<-marry Charles
    ** [I Diana take Charles to be my lawfully wedded other]
    !!>Charles<-marry Diana
    !!<Charles<-marry
    !<Diana<-marry
    <Charles<-marry

Sending the message UNFTRACE with an empty list switches the displaying of
tracing off, but doesn't actually untrace any method.  For example:

    person_flavour <- unftrace([]);

Sending the message FTRACE with an empty list switches the displaying
back on.


See also:
    TEACH *FLAVOURS
    HELP * BROWSESELF_MESSAGE, * TRACE
    REF * METAFLAVOUR_FLAVOUR


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