comment on

I have another custom approach:

sub new {
    my ($thing) = @_ ;
    
    my $class = ( ref($thing) or $thing ) ;
    my $self = bless({}, $class) ;
    
    $self->{'errMsg'} = "";

    # module user can set this e.g. to sub { carp($_[0]->{'errMsg'}) }
+ or something:
    $self->{'errHandler'};

    return $self ;
}

# Sets an error message, calls the error Handler, always returns undef
sub raiseError {
    my ($self, $string) = @_;
    $self->{'errMsg'} = $string;
    &{$self->{'errHandler'}}($self) if $self->{'errHandler'};
    return;
}

# returns error message and resets it to ""
sub error {
    my ($self) = @_;
    
    my $msg = $self->{'errMsg'};
    $self->{'errMsg'} = "";
    return $msg;
}


# ...

sub foo {
    my ($self) = @_;
    # do stuff
    if ($trouble) {
        return raiseError("foo: cannot do thisandthat");
    }
    # no error:
    # make sure to return true-evaluating or at least non-undef value
    return 1;
}
[download]

This way the module user can still use idioms like

$O->foo() or die "could not blabla: ".$O->error();
[download]

Users can still set the error handler to croak() if they wish. This could be extended ad nauseam: $debug switches, $exec_handler switch, method to get errMsg without resetting it -- you name it. I should probably put it in its own module, too, and inherit from that. I'm still not sure how to escalate errors when one method calls another. Maybe simply

sub bar {
    my ($self) = @_;

    foo() or return raiseError("bar failed to rhubarb: ".$self->error(
+));
    return 1;
}

# ...

$O->bar() or die "could not blabla: ".$O->error();
# "could not blabla: bar failed to rhubarb: foo: could not do thisandt
+hat"
[download]

In reply to Re^3: Error Handling with Packages by anjoschu
in thread Error Handling with Packages by Dru

Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
Want more info? How to link or How to display code and escape characters are good places to start.


go ahead... be a heretic
	PerlMonks