#---------------------------------------------------------------------
+---
# error()
# error($msg, ...)
# 
# May be called as a class or object method to set or retrieve the 
# package variable $ERROR (class method) or internal member 
# $self->{ _ERROR } (object method).  The presence of parameters indic
+ates
# that the error value should be set.  Undef is then returned.  In the
# abscence of parameters, the current error value is returned.
#---------------------------------------------------------------------
+---

sub error {
    my $self = shift;
    my $errvar;

    { 
    # get a reference to the object or package variable we're munging
    no strict qw( refs );
    $errvar = ref $self ? \$self->{ _ERROR } : \${"$self\::ERROR"};
    }
    if (@_) {
    # don't join if first arg is an object (may force stringification)
    $$errvar = ref($_[0]) ? shift : join('', @_);
    return undef;
    }
    else {
    return $$errvar;
    }
}
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