NAME
    BBCode::Parser - Parses BBCode tags

DESCRIPTION
    BBCode is a simplified markup language used in several online forums and
    bulletin boards. It originated with phpBB, and remains most popular
    among applications written in PHP. Generally, users author their posts
    in BBCode, and the forum converts it to a permitted subset of
    well-formed HTML.

    `BBCode::Parser' is a proper recursive parser for BBCode-formatted text.

OVERVIEW
    A `BBCode::Parser' object stores various settings that affect the
    parsing process. Simple settings are typically set when the parser is
    created using new(), but they can be queried using get() and altered
    using set().

    See "SETTINGS" for more information.

    In addition to the simple settings, specific BBCode tags (or classes of
    tags) can be permitted or forbidden, using permit() and forbid()
    respectively. By default, the only forbidden tag is `[HTML]', which is
    normally a security violation if permitted.

    See "CLASSES" for a list of tag classes.

    Once the parser has been configured appropriately, parse trees can be
    created using the parse() method. The parse tree will consist of objects
    derived from BBCode::Tag; the root of the tree will be a BBCode::Body
    object.

    Converting the parse tree to HTML is quite simple: call toHTML() on the
    root of the tree. Likewise, the parse tree can be converted back to
    BBCode by calling toBBCode(). See "METHODS" in BBCode::Tag to find out
    what other output methods are available.

SETTINGS
    The following settings can be manipulated using get() and set().

    css_prefix
        (Type: String; Default: "bbcode-")

        Many BBCode tags will add CSS classes as style hooks in the output
        HTML, such as `<div class="bbcode-quote">...</div>'. This setting
        allows you to override the naming scheme for those hooks. At the
        moment, more direct control of the CSS class names is not available.

    css_direct_styles
        (Type: Boolean; Default: FALSE)

        Certain style-related BBCode tags, such as [U] (underline) and [S]
        (strike-through) don't have a direct equivalent in modern XHTML 1.0
        Strict. If this value is TRUE, then the generated HTML will use a
        `style' attribute on a `<span>' tag to simulate the effects. If this
        value is FALSE, then the style attribute will be omitted. In either
        case, a `class' attribute is provided for use as a hook by external
        CSS stylesheets (not provided).

    follow_links
        (Type: Boolean; Default: FALSE)

        To prevent blog spam and the like, many search engines now allow
        HTML authors to indicate that specific URLs on a page should not be
        indexed. If this value is TRUE, then there will be nothing special
        about the URL (meaning that search engines are encouraged to follow
        the link). If this value is FALSE, then a `rel="nofollow"' attribute
        will be added wherever it makes sense (warning search engines that
        the link might be spam).

        Whether or not to set this value to TRUE will depend on what you're
        using `BBCode::Parser' for. If you're implementing a forum or
        bulletin board, TRUE might be reserved for senior, more trusted
        members. If you're implementing a blog, the value might be TRUE for
        the blog owner but FALSE for visitors.

        For more information, see
        http://www.google.com/webmasters/bot.html#www.

        (If you turn this setting on, `follow_override' behaves as if it
        were on as well. That way, users can explicitly mark links with
        `FOLLOW=0' if necessary.)

    follow_override
        (Type: Boolean; Default: FALSE)

        This BBCode implementation allows a user to override `follow_links'
        using a BBCode extension, the `FOLLOW' parameter. If this value is
        TRUE, the user can override `follow_links' with `FOLLOW=1';
        otherwise, the user must abide by `follow_links'.

        (However, a user can always specify `FOLLOW=0' regardless of this
        setting. If the user posting the link doesn't think the link is
        trustworthy, it's obviously not trustworthy.)

        The same considerations that apply to `follow_links' also apply to
        this setting.

    newwindow_links
        (Type: Boolean; Default: FALSE)

        For reasons largely having to do with site aesthetics, some site
        owners prefer for external links to each open in a new window using
        `<a target="_blank">'. For reasons largely having to do with
        browsing experience, some users prefer to summarily execute the
        aforementioned site owners in the most painful manner available. If
        you turn this option on, you will anger and frustrate people who
        suddenly find that their back buttons and/or tabs don't work right
        when they visit your site. Please take due consideration of that
        before setting this option to a TRUE value and taking choices away
        from the people reading your website.

    newwindow_override
        (Type: Boolean; Default: FALSE)

        This BBCode implementation allows a user to override
        `newwindow_links' using a BBCode extension, the `NEWWINDOW'
        parameter. If this value is TRUE, the user can force the link to
        open in the same window with `NEWWINDOW=0', or force the link to
        open in a new window with `NEWWINDOW=1'. If this value is FALSE, the
        user has no say whatsoever.

        The same considerations that apply to `newwindow_links' also apply
        to this setting, but in drastically reduced form. If you feel the
        need to open links in new windows, please do it by turning this
        setting on and leaving `newwindow_links' off.

    allow_image_bullets
        (Type: Boolean; Default: TRUE)

        This setting allows you to restrict users from creating lists with
        custom bullets.

CLASSES
    BLOCK
        Tags with the `BLOCK' class are those that translate into
        block-level elements in HTML, e.g. `[QUOTE]', which becomes
        `<blockquote>'. They represent blocks of content that stand alone
        from other blocks, often with vertical padding to separate them
        visually.

        In general, `BLOCK' tags are not allowed inside `INLINE' tags.

    INLINE
        Tags with the `INLINE' class are those that translate into inline
        elements in HTML, e.g. `[URL]', which becomes `<a>'. They represent
        content that's still part of the current flow of text, not the start
        of a new block.

    LINK
        Tags with the `LINK' class are hyperlinks to external resources. At
        the moment, the two tags with the `LINK' class are `[URL]' and
        `[EMAIL]'.

    TEXT
        Tags with the `TEXT' class are plain text. At the moment, the three
        tags with the `TEXT' class are `[TEXT]', `[ENT]', and `[BR]'.

METHODS
  DEFAULT

            my $tree = BBCode::Parser->DEFAULT->parse($code);

    `DEFAULT' returns the default parser. If you change the default parser,
    all future parsers created with new() will incorporate your changes.
    However, all existing parsers will be unaffected.

  clone

            my $parser = BBCode::Parser->new(follow_links => 1);
            my $clone = $parser->clone;
            $clone->forbid('IMG');
            printf "[IMG] is%s OK\n", ($parser->isPermitted('IMG') ? "" : " not");
            # Prints "[IMG] is OK", since forbid('IMG') applies only to the clone.

    `clone' creates a new parser that copies the settings of an existing
    parser. After cloning, the two parsers are completely independent;
    changing settings in one does not affect the other.

    If any arguments are given, they are handed off to the set() method.

  new

            my $parser = BBCode::Parser->new(%args);

    `new' creates a new `BBCode::Parser'. Any arguments are handed off to
    the set() method.

  get

            if($parser->get('follow_override')) {
                    # [URL FOLLOW] permitted
            } else {
                    # [URL FOLLOW] forbidden
            }

    `get' fetches the current settings for the given parser. See "SETTINGS"
    for a list of available settings.

  set

            $parser->set(follow_override => 1);

    `set' alters the settings for the given parser. See "SETTINGS" for a
    list of available settings.

  addTag

    TODO: Implement and document

  permit

            $parser->permit(qw(:INLINE !:LINK));

    `permit' adds TAGs and :CLASSes to the list of permitted tags. Use '!'
    in front of a tag or class to negate the meaning.

  forbid

            $parser->forbid(qw(:ALL !:TEXT));

    `forbid' adds TAGs and :CLASSes to the list of forbidden tags. Use '!'
    in front of a tag or class to negate the meaning.

  isPermitted

            if($parser->isPermitted('IMG')) {
                    # Yay, [IMG] tags
            } else {
                    # Darn, no [IMG] tags
            }

    `isPermitted' checks if a tag is permitted by the current settings.

  parse

            my $tree = $parser->parse('[b]BBCode[/b] text.');

    `parse' creates a parse tree for the given BBCode. The result is a tree
    of BBCode::Tag objects. The most common use of the parse tree is to
    convert it to HTML using BBCode::Tag->toHTML():

            my $html = $tree->toHTML;

SEE ALSO
    BBCode::Tag

    svn://chronos-tachyon.net/projects/BBCode-Parser

AUTHOR
    Donald King <dlking@cpan.org>

