XML::Parser::Expat - phpMan

NAME
    XML::Parser::Expat - Lowlevel access to James Clark's expat XML parser

SYNOPSIS
     use XML::Parser::Expat;

     $parser = XML::Parser::Expat->new;
     $parser->setHandlers('Start' => \&sh,
                          'End'   => \&eh,
                          'Char'  => \&ch);
     open(my $fh, '<', 'info.xml') or die "Couldn't open";
     $parser->parse($fh);
     close($fh);
     # $parser->parse('<foo id="me"> here <em>we</em> go </foo>');

     sub sh
     {
       my ($p, $el, %atts) = @_;
       $p->setHandlers('Char' => \&spec)
         if ($el eq 'special');
       ...
     }

     sub eh
     {
       my ($p, $el) = @_;
       $p->setHandlers('Char' => \&ch)  # Special elements won't contain
         if ($el eq 'special');         # other special elements
       ...
     }

DESCRIPTION
    This module provides an interface to James Clark's XML parser, expat. As
    in expat, a single instance of the parser can only parse one document.
    Calls to parsestring after the first for a given instance will die.

    Expat (and XML::Parser::Expat) are event based. As the parser recognizes
    parts of the document (say the start or end of an XML element), then any
    handlers registered for that type of an event are called with suitable
    parameters.

METHODS
    new This is a class method, the constructor for XML::Parser::Expat.
        Options are passed as keyword value pairs. The recognized options
        are:

        *   ProtocolEncoding

            The protocol encoding name. The default is none. The expat
            built-in encodings are: "UTF-8", "ISO-8859-1", "UTF-16", and
            "US-ASCII". Other encodings may be used if they have encoding
            maps in one of the directories in the @Encoding_Path list.
            Setting the protocol encoding overrides any encoding in the XML
            declaration.

        *   Namespaces

            When this option is given with a true value, then the parser
            does namespace processing. By default, namespace processing is
            turned off. When it is turned on, the parser consumes *xmlns*
            attributes and strips off prefixes from element and attributes
            names where those prefixes have a defined namespace. A name's
            namespace can be found using the "namespace" method and two
            names can be checked for absolute equality with the "eq_name"
            method.

        *   NoExpand

            Normally, the parser will try to expand references to entities
            defined in the internal subset. If this option is set to a true
            value, and a default handler is also set, then the default
            handler will be called when an entity reference is seen in text.
            This has no effect if a default handler has not been registered,
            and it has no effect on the expansion of entity references
            inside attribute values.

        *   Stream_Delimiter

            This option takes a string value. When this string is found
            alone on a line while parsing from a stream, then the parse is
            ended as if it saw an end of file. The intended use is with a
            stream of xml documents in a MIME multipart format. The string
            should not contain a trailing newline.

        *   ErrorContext

            When this option is defined, errors are reported in context. The
            value of ErrorContext should be the number of lines to show on
            either side of the line in which the error occurred.

        *   ParseParamEnt

            Unless standalone is set to "yes" in the XML declaration,
            setting this to a true value allows the external DTD to be read,
            and parameter entities to be parsed and expanded.

        *   Base

            The base to use for relative pathnames or URLs. This can also be
            done by using the base method.

    setHandlers(TYPE, HANDLER [, TYPE, HANDLER [...]])
        This method registers handlers for the various events. If no
        handlers are registered, then a call to parsestring or parsefile
        will only determine if the corresponding XML document is well formed
        (by returning without error.) This may be called from within a
        handler, after the parse has started.

        Setting a handler to something that evaluates to false unsets that
        handler.

        This method returns a list of type, handler pairs corresponding to
        the input. The handlers returned are the ones that were in effect
        before the call to setHandlers.

        The recognized events and the parameters passed to the corresponding
        handlers are:

        *   Start (Parser, Element [, Attr, Val [,...]])

            This event is generated when an XML start tag is recognized.
            Parser is an XML::Parser::Expat instance. Element is the name of
            the XML element that is opened with the start tag. The Attr &
            Val pairs are generated for each attribute in the start tag.

        *   End (Parser, Element)

            This event is generated when an XML end tag is recognized. Note
            that an XML empty tag (<foo/>) generates both a start and an end
            event.

            There is always a lower level start and end handler installed
            that wrap the corresponding callbacks. This is to handle the
            context mechanism. A consequence of this is that the default
            handler (see below) will not see a start tag or end tag unless
            the default_current method is called.

        *   Char (Parser, String)

            This event is generated when non-markup is recognized. The
            non-markup sequence of characters is in String. A single
            non-markup sequence of characters may generate multiple calls to
            this handler. Whatever the encoding of the string in the
            original document, this is given to the handler in UTF-8.

        *   Proc (Parser, Target, Data)

            This event is generated when a processing instruction is
            recognized.

        *   Comment (Parser, String)

            This event is generated when a comment is recognized.

        *   CdataStart (Parser)

            This is called at the start of a CDATA section.

        *   CdataEnd (Parser)

            This is called at the end of a CDATA section.

        *   Default (Parser, String)

            This is called for any characters that don't have a registered
            handler. This includes both characters that are part of markup
            for which no events are generated (markup declarations) and
            characters that could generate events, but for which no handler
            has been registered.

            Whatever the encoding in the original document, the string is
            returned to the handler in UTF-8.

        *   Unparsed (Parser, Entity, Base, Sysid, Pubid, Notation)

            This is called for a declaration of an unparsed entity. Entity
            is the name of the entity. Base is the base to be used for
            resolving a relative URI. Sysid is the system id. Pubid is the
            public id. Notation is the notation name. Base and Pubid may be
            undefined.

        *   Notation (Parser, Notation, Base, Sysid, Pubid)

            This is called for a declaration of notation. Notation is the
            notation name. Base is the base to be used for resolving a
            relative URI. Sysid is the system id. Pubid is the public id.
            Base, Sysid, and Pubid may all be undefined.

        *   ExternEnt (Parser, Base, Sysid, Pubid)

            This is called when an external entity is referenced. Base is
            the base to be used for resolving a relative URI. Sysid is the
            system id. Pubid is the public id. Base, and Pubid may be
            undefined.

            This handler should either return a string, which represents the
            contents of the external entity, or return an open filehandle
            that can be read to obtain the contents of the external entity,
            or return undef, which indicates the external entity couldn't be
            found and will generate a parse error.

            If an open filehandle is returned, it must be returned as either
            a glob (*FOO) or as a reference to a glob (e.g. an instance of
            IO::Handle).

        *   ExternEntFin (Parser)

            This is called after an external entity has been parsed. It
            allows applications to perform cleanup on actions performed in
            the above ExternEnt handler.

        *   Entity (Parser, Name, Val, Sysid, Pubid, Ndata, IsParam)

            This is called when an entity is declared. For internal
            entities, the Val parameter will contain the value and the
            remaining three parameters will be undefined. For external
            entities, the Val parameter will be undefined, the Sysid
            parameter will have the system id, the Pubid parameter will have
            the public id if it was provided (it will be undefined
            otherwise), the Ndata parameter will contain the notation for
            unparsed entities. If this is a parameter entity declaration,
            then the IsParam parameter is true.

            Note that this handler and the Unparsed handler above overlap.
            If both are set, then this handler will not be called for
            unparsed entities.

        *   Element (Parser, Name, Model)

            The element handler is called when an element declaration is
            found. Name is the element name, and Model is the content model
            as an XML::Parser::ContentModel object. See
            "XML::Parser::ContentModel Methods" for methods available for
            this class.

        *   Attlist (Parser, Elname, Attname, Type, Default, Fixed)

            This handler is called for each attribute in an ATTLIST
            declaration. So an ATTLIST declaration that has multiple
            attributes will generate multiple calls to this handler. The
            Elname parameter is the name of the element with which the
            attribute is being associated. The Attname parameter is the name
            of the attribute. Type is the attribute type, given as a string.
            Default is the default value, which will either be "#REQUIRED",
            "#IMPLIED" or a quoted string (i.e. the returned string will
            begin and end with a quote character). If Fixed is true, then
            this is a fixed attribute.

        *   Doctype (Parser, Name, Sysid, Pubid, Internal)

            This handler is called for DOCTYPE declarations. Name is the
            document type name. Sysid is the system id of the document type,
            if it was provided, otherwise it's undefined. Pubid is the
            public id of the document type, which will be undefined if no
            public id was given. Internal will be true or false, indicating
            whether or not the doctype declaration contains an internal
            subset.

        *   DoctypeFin (Parser)

            This handler is called after parsing of the DOCTYPE declaration
            has finished, including any internal or external DTD
            declarations.

        *   XMLDecl (Parser, Version, Encoding, Standalone)

            This handler is called for XML declarations. Version is a string
            containing the version. Encoding is either undefined or contains
            an encoding string. Standalone is either undefined, or true or
            false. Undefined indicates that no standalone parameter was
            given in the XML declaration. True or false indicates "yes" or
            "no" respectively.

    namespace(name)
        Return the URI of the namespace that the name belongs to. If the
        name doesn't belong to any namespace, an undef is returned. This is
        only valid on names received through the Start or End handlers from
        a single document, or through a call to the generate_ns_name method.
        In other words, don't use names generated from one instance of
        XML::Parser::Expat with other instances.

    eq_name(name1, name2)
        Return true if name1 and name2 are identical (i.e. same name and
        from the same namespace.) This is only meaningful if both names were
        obtained through the Start or End handlers from a single document,
        or through a call to the generate_ns_name method.

    generate_ns_name(name, namespace)
        Return a name, associated with a given namespace, good for using
        with the above 2 methods. The namespace argument should be the
        namespace URI, not a prefix.

    new_ns_prefixes
        When called from a start tag handler, returns namespace prefixes
        declared with this start tag. If called elsewhere (or if there were
        no namespace prefixes declared), it returns an empty list. Setting
        of the default namespace is indicated with '#default' as a prefix.

    expand_ns_prefix(prefix)
        Return the uri to which the given prefix is currently bound. Returns
        undef if the prefix isn't currently bound. Use '#default' to find
        the current binding of the default namespace (if any).

    current_ns_prefixes
        Return a list of currently bound namespace prefixes. The order of
        the the prefixes in the list has no meaning. If the default
        namespace is currently bound, '#default' appears in the list.

    recognized_string
        Returns the string from the document that was recognized in order to
        call the current handler. For instance, when called from a start
        handler, it will give us the start-tag string. The string is encoded
        in UTF-8. This method doesn't return a meaningful string inside
        declaration handlers.

    original_string
        Returns the verbatim string from the document that was recognized in
        order to call the current handler. The string is in the original
        document encoding. This method doesn't return a meaningful string
        inside declaration handlers.

    default_current
        When called from a handler, causes the sequence of characters that
        generated the corresponding event to be sent to the default handler
        (if one is registered). Use of this method is deprecated in favor
        the recognized_string method, which you can use without installing a
        default handler. This method doesn't deliver a meaningful string to
        the default handler when called from inside declaration handlers.

    xpcroak(message)
        Concatenate onto the given message the current line number within
        the XML document plus the message implied by ErrorContext. Then
        croak with the formed message.

    xpcarp(message)
        Concatenate onto the given message the current line number within
        the XML document plus the message implied by ErrorContext. Then carp
        with the formed message.

    current_line
        Returns the line number of the current position of the parse.

    current_column
        Returns the column number of the current position of the parse.

    current_byte
        Returns the current position of the parse.

    base([NEWBASE]);
        Returns the current value of the base for resolving relative URIs.
        If NEWBASE is supplied, changes the base to that value.

    context
        Returns a list of element names that represent open elements, with
        the last one being the innermost. Inside start and end tag handlers,
        this will be the tag of the parent element.

    current_element
        Returns the name of the innermost currently opened element. Inside
        start or end handlers, returns the parent of the element associated
        with those tags.

    in_element(NAME)
        Returns true if NAME is equal to the name of the innermost currently
        opened element. If namespace processing is being used and you want
        to check against a name that may be in a namespace, then use the
        generate_ns_name method to create the NAME argument.

    within_element(NAME)
        Returns the number of times the given name appears in the context
        list. If namespace processing is being used and you want to check
        against a name that may be in a namespace, then use the
        generate_ns_name method to create the NAME argument.

    depth
        Returns the size of the context list.

    element_index
        Returns an integer that is the depth-first visit order of the
        current element. This will be zero outside of the root element. For
        example, this will return 1 when called from the start handler for
        the root element start tag.

    skip_until(INDEX)
        INDEX is an integer that represents an element index. When this
        method is called, all handlers are suspended until the start tag for
        an element that has an index number equal to INDEX is seen. If a
        start handler has been set, then this is the first tag that the
        start handler will see after skip_until has been called.

    position_in_context(LINES)
        Returns a string that shows the current parse position. LINES should
        be an integer >= 0 that represents the number of lines on either
        side of the current parse line to place into the returned string.

    xml_escape(TEXT [, CHAR [, CHAR ...]])
        Returns TEXT with markup characters turned into character entities.
        Any additional characters provided as arguments are also turned into
        character references where found in TEXT.

    parse (SOURCE)
        The SOURCE parameter should either be a string containing the whole
        XML document, or it should be an open IO::Handle. Only a single
        document may be parsed for a given instance of XML::Parser::Expat,
        so this will croak if it's been called previously for this instance.

    parsestring(XML_DOC_STRING)
        Parses the given string as an XML document. Only a single document
        may be parsed for a given instance of XML::Parser::Expat, so this
        will die if either parsestring or parsefile has been called for this
        instance previously.

        This method is deprecated in favor of the parse method.

    parsefile(FILENAME)
        Parses the XML document in the given file. Will die if parsestring
        or parsefile has been called previously for this instance.

    is_defaulted(ATTNAME)
        NO LONGER WORKS. To find out if an attribute is defaulted please use
        the specified_attr method.

    specified_attr
        When the start handler receives lists of attributes and values, the
        non-defaulted (i.e. explicitly specified) attributes occur in the
        list first. This method returns the number of specified items in the
        list. So if this number is equal to the length of the list, there
        were no defaulted values. Otherwise the number points to the index
        of the first defaulted attribute name.

    finish
        Unsets all handlers (including internal ones that set context), but
        expat continues parsing to the end of the document or until it finds
        an error. It should finish up a lot faster than with the handlers
        set.

    release
        There are data structures used by XML::Parser::Expat that have
        circular references. This means that these structures will never be
        garbage collected unless these references are explicitly broken.
        Calling this method breaks those references (and makes the instance
        unusable.)

        Normally, higher level calls handle this for you, but if you are
        using XML::Parser::Expat directly, then it's your responsibility to
        call it.

  XML::Parser::ContentModel Methods
    The element declaration handlers are passed objects of this class as the
    content model of the element declaration. They also represent content
    particles, components of a content model.

    When referred to as a string, these objects are automagicly converted to
    a string representation of the model (or content particle).

    isempty
        This method returns true if the object is "EMPTY", false otherwise.

    isany
        This method returns true if the object is "ANY", false otherwise.

    ismixed
        This method returns true if the object is "(#PCDATA)" or
        "(#PCDATA|...)*", false otherwise.

    isname
        This method returns if the object is an element name.

    ischoice
        This method returns true if the object is a choice of content
        particles.

    isseq
        This method returns true if the object is a sequence of content
        particles.

    quant
        This method returns undef or a string representing the quantifier
        ('?', '*', '+') associated with the model or particle.

    children
        This method returns undef or (for mixed, choice, and sequence types)
        an array of component content particles. There will always be at
        least one component for choices and sequences, but for a mixed
        content model of pure PCDATA, "(#PCDATA)", then an undef is
        returned.

  XML::Parser::ExpatNB Methods
    The class XML::Parser::ExpatNB is a subclass of XML::Parser::Expat used
    for non-blocking access to the expat library. It does not support the
    parse, parsestring, or parsefile methods, but it does have these
    additional methods:

    parse_more(DATA)
        Feed expat more text to munch on.

    parse_done
        Tell expat that it's gotten the whole document.

FUNCTIONS
    XML::Parser::Expat::load_encoding(ENCODING)
        Load an external encoding. ENCODING is either the name of an
        encoding or the name of a file. The basename is converted to
        lowercase and a '.enc' extension is appended unless there's one
        already there. Then, unless it's an absolute pathname (i.e. begins
        with '/'), the first file by that name discovered in the
        @Encoding_Path path list is used.

        The encoding in the file is loaded and kept in the %Encoding_Table
        table. Earlier encodings of the same name are replaced.

        This function is automatically called by expat when it encounters an
        encoding it doesn't know about. Expat shouldn't call this twice for
        the same encoding name. The only reason users should use this
        function is to explicitly load an encoding not contained in the
        @Encoding_Path list.

AUTHORS
    Larry Wall <larry AT wall.org> wrote version 1.0.

    Clark Cooper <coopercc AT netheaven.com> picked up support, changed the API
    for this version (2.x), provided documentation, and added some standard
    package features.