in reply to (tye)Re: Reference as the only Object element
in thread Reference as the only Object element

> Try $self=[@_];

Where? :-)

What I mean with "pass this reference" is actually "clone a reference". Again assume you have a parser and this parser is filling you a structure (basically a list). You let your parser return a reference to the structure created and you would like your Entry Object to store THAT Reference.

This seems not possible. BTW: You throw up an interesting point:

>Anyway, I wouldn't ever put \@_ into an object as changes...

How do you declare an object whose only element is a reference to a list (or hash for that matter)?

Thanks Richard

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Re: Re: (tye)Re: Reference as the only Object element
by dragonchild (Archbishop) on Nov 02, 2001 at 21:58 UTC
    You're confusing the implentation of the object and the attributes of that object.

    If you want to declare an object which is implented as a list, I'd do something like: 

    sub new {
    my $class = shift;
    my $self = [@_];
    bless $self, $class;
    return $self;
}

sub getList {
    my $self = shift;

    if (wantarray) {
        return @$self;
    else {
        return [@$self];
    }
}

    [download]

    If you wanted to have a class which had only one attribute and that attribute was a list, I'd do something like: 

    sub new {
    my $class = shift;

    my $self = {};
    bless $self, $class;

    $self->{LIST} = [@_];

    return $self;
}

sub getList {
    my $self = shift;

    if (wantarray) {
        return @{$self->{LIST}};
    else {
        return [@$self->{LIST}];
    }
}

    [download]
    Then, you would add setters as well. However, we already have something like this, in the form of tie and Tie::Array (and its cousin Tie::Hash). Check those out.

    ------
    We are the carpenters and bricklayers of the Information Age.

    Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.

[reply]
[d/l]
[select]

      After chatting with Fatvamp, I think what he wants is something close to this: 

      sub new {
    return bless [], shift;
}

sub addItems {
    my $self= shift;
    unshift @$self, @_;
}

sub setList {
    my $self= shift;
    my( $ref )= @_;
    if(  1 == @_  &&  ref($ref)  ) {
        @$self= @$ref;
    } else {
        @$self= @_;
    }
}

sub getItem {
    my $self= shift;
    my $idx= shift;
    return $self->[$idx];
}

sub getList {
    my $self= shift;
    if (wantarray) {
        return @$self;
    } else {
        return [@$self];
    }
}

      [download]

              - tye (but my friends call me "Tye")
[reply]
[d/l]
        Basically, he wants some class that acts as an array. That works just fine.

        I'd make one reccomendation - be positive that addItem() is always going to do an unshift. It's more intuitive to add to the end vs. the beginning of a list.

        ------
        We are the carpenters and bricklayers of the Information Age.

        Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.

[reply]

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