This is Info file pm.info, produced by Makeinfo version 1.68 from the input file bigpm.texi.  File: pm.info, Node: XML/PPMConfig, Next: XML/PYX, Prev: XML/PPD, Up: Module List PPMConfig file format and XML parsing elements ********************************************** NAME ==== XML::PPMConfig - PPMConfig file format and XML parsing elements SYNOPSIS ======== use XML::Parser; use XML::PPMConfig; $p = new XML::Parser( Style => 'Objects', Pkg => 'XML::PPMConfig' ); ... DESCRIPTION =========== This module provides a set of classes for parsing PPM configuration files using the XML::Parser module. All of the elements unique to a PPM configuration file are derived from `XML::ValidatingElement'. There are also several classes rebuilt here which are derived from elements in `XML::PPD' as we can include a PPD file within our own INSTPPD element. MAJOR ELEMENTS ============== PPMCONFIG --------- Defines a PPM configuration file. The root of a PPMConfig document is always a PPMCONFIG element. PACKAGE ------- Child of PPMCONFIG, used to describe a Perl Package which has already been installed. Multiple instances are valid. The PACKAGE element allows for the following attributes: NAME Name of the package as given in it's PPD MINOR ELEMENTS ============== PPMVER ------ Child of PPMCONFIG, used to state the version of PPM for which this configuration file is valid. A single instance should be present. PLATFORM -------- Child of PPMCONFIG, used to specify the platform of the target machine. A single instance should be present. The PLATFORM element allows for the following attributes: OSVALUE Description of the local operating system as defined in the Config.pm file under 'osname'. OSVERSION Version of the local operating system. CPU Description of the CPU in the local system. The following list of possible values was taken from the OSD Specification: x86 mips alpha ppc sparc 680x0 LANGUAGE Description of the language used on the local system as specified by the language codes in ISO 639. REPOSITORY ---------- Child of PPMCONFIG, used to specify a repository where Perl Packages can be found. Multiple instances are valid. The REPOSITORY element allows for the following attributes: NAME Name by which the repository will be known (e.g. "ActiveState"). LOCATION An URL or directory where the repository can be found. USERNAME Optional username for a repository requiring authenticated connection. PASSWORD Optional password for a repository requiring authenticated connection. SUMMARYFILE Optional package summary filename. If this file exists on the repository, its contents can be retrieved using PPM::RepositorySummary(). The contents are not strictly enforced by PPM.pm, however ppm.pl expects this to be a file with the following format (for display with the 'summary' command): Agent [2.91]: supplies agentspace methods for perl5. Apache-OutputChain [0.06]: chain stacked Perl handlers [etc.] OPTIONS ------- Child of PPMCONFIG, used to specify the current configuration options for PPM. A single instance should be present. The OPTIONS element allows for the following attributes: IGNORECASE Sets case-sensitive searching. Can be either '1' or '0'. CLEAN Sets removal of temporarily files. Can be either '1' or '0'. CONFIRM Sets confirmation of all installs/removals/upgrades. Can be either '1' or '0'. BUILDDIR Directory in which packages will be unpacked before their installation. ROOT Directory under which packages should be installed on the local system. TRACE Level of tracing (0 is no tracing, 4 is max tracing). TRACEFILE File to which trace information will be written. VERBOSE Controls whether query and search results are verbose (1 == verbose, 0 == no). PPMPRECIOUS ----------- Child of PPMCONFIG, used to specify the modules which PPM itself is dependant upon. A single instance should be present. LOCATION -------- Child of PACKAGE, used to specify locations at which to search for updated versions of the PPD file for this package. Its value can be either a directory or an Internet address. A single instance should be present. INSTDATE -------- Child of PACKAGE, used to specify the date on which the Perl Package was installed. A single instance should be present. INSTROOT -------- Child of PACKAGE, used to specify the root directory that the Perl Package was installed into. A single instance should be present. INSTPACKLIST ------------ Child of PACKAGE, used to specify a reference to the packlist for this Perl Package; a file containing a list of all of the files which were installed. A single instance should be present. INSTPPD ------- Child of PACKAGE, used to hold a copy of the PPD from which Perl Packages were installed. Multiple instances are valid. DOCUMENT TYPE DEFINITION ======================== The DTD for PPMConfig documents is available from the ActiveState website and the latest version can be found at: http://www.ActiveState.com/PPM/DTD/ppmconfig.dtd This revision of the `XML::PPMConfig' module implements the following DTD: SAMPLE PPMConfig FILE ===================== The following is a sample PPMConfig file. Note that this may not be a current description of this module and is for sample purposes only. 1,0,0,0 PPM;libnet;Archive-Tar;Compress-Zlib;libwww-perl g:/packages c:/perllib/lib/site/MSWin32-x86/auto/AtExit/.packlist c:/perllib Sun Mar 8 02:56:31 1998 AtExit Register a subroutine to be invoked at program -exit time. Brad Appleton (Brad_Appleton-GBDA001@email.mot.com) KNOWN BUGS/ISSUES ================= Elements which are required to be empty (e.g. REPOSITORY) are not enforced as such. Notations above about elements for which "only one instance" or "multiple instances" are valid are not enforced; this primarily a guideline for generating your own PPD files. Currently, this module creates new classes within it's own namespace for all of the PPD elements which can be contained within the INSTPPD element. A suitable method for importing the entire XML::PPD:: namespace should be found in order to make this cleaner. AUTHORS ======= Graham TerMarsch Murray Nesbitt Dick Hardt HISTORY ======= v0.1 - Initial release SEE ALSO ======== `XML::ValidatingElement' in this node, *Note XML/Parser: XML/Parser,, *Note XML/PPD: XML/PPD, .  File: pm.info, Node: XML/PYX, Next: XML/Parser, Prev: XML/PPMConfig, Up: Module List XML to PYX generator ******************** NAME ==== XML::PYX - XML to PYX generator SYNOPSIS ======== use XML::PYX; my $parser = XML::PYX::Parser->new; my $string = $parser->parsefile($filename); DESCRIPTION =========== After reading about PYX on XML.com, I thought it was a pretty cool idea, so I built this, to generate PYX from XML using perl. See http://www.xml.com/pub/2000/03/15/feature/index.html for an excellent introduction. The package contains 2 usable packages, and 3 utilities that are probably currently more use than the module: pyx - a XML to PYX converter using XML::Parser pyxv - a Validating XML to PYX converter using XML::Checker::Parser pyxw - a PYX to XML converter pyxhtml - an HTML to PYX converter using HTML::TreeBuilder All these utilities can be pipelined together, so you can have: pyx test.xml | grep -v "^-" | pyxw > new.xml Which should remove all text from an XML file (leaving only tags). The 2 packages are XML::PYX::Parser and XML::PYX::Parser::ToCSF. The former is a direct subclass of XML::Parser that simply returns a PYX string on a call to parse or parsefile. The latter stands for *To Currently Selected Filehandle*. Instead of returning a string, it sends output directly to the currently selected filehandle. This is much better for pipelined utilities for obvious reasons. There's a special variable: $XML::PYX::Lame. Set it to 1 to use a "Lame" parser that simply uses regexps. This is useful, for example, if you are changing the input to invalid XML for some reason. You can then use $XML::PYX::Lame = 1 to enable the non-xml parser. It does check for some things, like balanced tags, but otherwise it's pretty lame :) Lame mode is enabled for pyx and pyxw with the -l option. AUTHOR ====== Matt Sergeant, matt@sergeant.org  File: pm.info, Node: XML/Parser, Next: XML/Parser/EasyTree, Prev: XML/PYX, Up: Module List A perl module for parsing XML documents *************************************** NAME ==== XML::Parser - A perl module for parsing XML documents SYNOPSIS ======== use XML::Parser; $p1 = new XML::Parser(Style => 'Debug'); $p1->parsefile('REC-xml-19980210.xml'); $p1->parse('Hello World'); # Alternative $p2 = new XML::Parser(Handlers => {Start => \&handle_start, End => \&handle_end, Char => \&handle_char}); $p2->parse($socket); # Another alternative $p3 = new XML::Parser(ErrorContext => 2); $p3->setHandlers(Char => \&text, Default => \&other); open(FOO, 'xmlgenerator |'); $p3->parse(*FOO, ProtocolEncoding => 'ISO-8859-1'); close(FOO); $p3->parsefile('junk.xml', ErrorContext => 3); DESCRIPTION =========== This module provides ways to parse XML documents. It is built on top of *Note XML/Parser/Expat: XML/Parser/Expat,, which is a lower level interface to James Clark's expat library. Each call to one of the parsing methods creates a new instance of XML::Parser::Expat which is then used to parse the document. Expat options may be provided when the XML::Parser object is created. These options are then passed on to the Expat object on each parse call. They can also be given as extra arguments to the parse methods, in which case they override options given at XML::Parser creation time. The behavior of the parser is controlled either by ``' in this node' and/or ``' in this node' options, or by `' in this node method. These all provide mechanisms for XML::Parser to set the handlers needed by XML::Parser::Expat. If neither Style nor Handlers are specified, then parsing just checks the document for being well-formed. When underlying handlers get called, they receive as their first parameter the *Expat* object, not the Parser object. METHODS ======= new This is a class method, the constructor for XML::Parser. Options are passed as keyword value pairs. Recognized options are: * Style This option provides an easy way to create a given style of parser. The built in styles are: `"Debug"' in this node, `"Subs"' in this node, `"Tree"' in this node, `"Objects"' in this node, and `"Stream"' in this node. Custom styles can be provided by giving a full package name containing at least one '::'. This package should then have subs defined for each handler it wishes to have installed. See `"STYLES"' in this node below for a discussion of each built in style. * Handlers When provided, this option should be an anonymous hash containing as keys the type of handler and as values a sub reference to handle that type of event. All the handlers get passed as their 1st parameter the instance of expat that is parsing the document. Further details on handlers can be found in `"HANDLERS"' in this node. Any handler set here overrides the corresponding handler set with the Style option. * Pkg Some styles will refer to subs defined in this package. If not provided, it defaults to the package which called the constructor. * ErrorContext This is an Expat option. When this option is defined, errors are reported in context. The value should be the number of lines to show on either side of the line in which the error occurred. * ProtocolEncoding This is an Expat option. This sets the protocol encoding name. It defaults to none. The 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. Check `"ENCODINGS"' in this node for more information on encoding maps. Setting the protocol encoding overrides any encoding in the XML declaration. * Namespaces This is an Expat option. If this is set to a true value, then namespace processing is done during the parse. See `"Namespaces"', *Note XML/Parser/Expat: XML/Parser/Expat, for further discussion of namespace processing. * NoExpand This is an Expat option. 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 is an Expat option. It 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. * ParseParamEnt This is an Expat option. 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. * NoLWP This option has no effect if the ExternEnt or ExternEntFin handlers are directly set. Otherwise, if true, it forces the use of a file based external entity handler. * Non-Expat-Options If provided, this should be an anonymous hash whose keys are options that shouldn't be passed to Expat. This should only be of concern to those subclassing XML::Parser. setHandlers(TYPE, HANDLER [, TYPE, HANDLER [...]]) This method registers handlers for various parser events. It overrides any previous handlers registered through the Style or Handler options or through earlier calls to setHandlers. By providing a false or undefined value as the handler, the existing handler can be unset. This method returns a list of type, handler pairs corresponding to the input. The handlers returned are the ones that were in effect prior to the call. See a description of the handler types in `"HANDLERS"' in this node. parse(SOURCE [, OPT => OPT_VALUE [...]]) The SOURCE parameter should either be a string containing the whole XML document, or it should be an open IO::Handle. Constructor options to XML::Parser::Expat given as keyword-value pairs may follow the SOURCE parameter. These override, for this call, any options or attributes passed through from the XML::Parser instance. A die call is thrown if a parse error occurs. Otherwise it will return 1 or whatever is returned from the Final handler, if one is installed. In other words, what parse may return depends on the style. parsestring This is just an alias for parse for backwards compatibility. parsefile(FILE [, OPT => OPT_VALUE [...]]) Open FILE for reading, then call parse with the open handle. The file is closed no matter how parse returns. Returns what parse returns. parse_start([ OPT => OPT_VALUE [...]]) Create and return a new instance of XML::Parser::ExpatNB. Constructor options may be provided. If an init handler has been provided, it is called before returning the ExpatNB object. Documents are parsed by making incremental calls to the parse_more method of this object, which takes a string. A single call to the parse_done method of this object, which takes no arguments, indicates that the document is finished. If there is a final handler installed, it is executed by the parse_done method before returning and the parse_done method returns whatever is returned by the final handler. HANDLERS ======== Expat is an event based parser. As the parser recognizes parts of the document (say the start or end tag for an XML element), then any handlers registered for that type of an event are called with suitable parameters. All handlers receive an instance of XML::Parser::Expat as their first argument. See `"METHODS"', *Note XML/Parser/Expat: XML/Parser/Expat, for a discussion of the methods that can be called on this object. Init (Expat) ------------- This is called just before the parsing of the document starts. Final (Expat) -------------- This is called just after parsing has finished, but only if no errors occurred during the parse. Parse returns what this returns. Start (Expat, Element [, Attr, Val [,...]]) -------------------------------------------- This event is generated when an XML start tag is recognized. Element is the name of the XML element type that is opened with the start tag. The Attr & Val pairs are generated for each attribute in the start tag. End (Expat, Element) --------------------- This event is generated when an XML end tag is recognized. Note that an XML empty tag () generates both a start and an end event. Char (Expat, 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 (Expat, Target, Data) --------------------------- This event is generated when a processing instruction is recognized. Comment (Expat, Data) ---------------------- This event is generated when a comment is recognized. CdataStart (Expat) ------------------ This is called at the start of a CDATA section. CdataEnd (Expat) ----------------- This is called at the end of a CDATA section. Default (Expat, 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 (Expat, 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 (Expat, 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 (Expat, 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). A default handler is installed for this event. The default handler is XML::Parser::lwp_ext_ent_handler unless the NoLWP option was provided with a true value, otherwise XML::Parser::file_ext_ent_handler is the default handler for external entities. Even without the NoLWP option, if the URI or LWP modules are missing, the file based handler ends up being used after giving a warning on the first external entity reference. The LWP external entity handler will use proxies defined in the environment (http_proxy, ftp_proxy, etc.). Please note that the LWP external entity handler reads the entire entity into a string and returns it, where as the file handler opens a filehandle. Also note that the file external entity handler will likely choke on absolute URIs or file names that don't fit the conventions of the local operating system. The expat base method can be used to set a basename for relative pathnames. If no basename is given, or if the basename is itself a relative name, then it is relative to the current working directory. ExternEntFin (Expat) -------------------- This is called after parsing an external entity. It's not called unless an ExternEnt handler is also set. There is a default handler installed that pairs with the default ExternEnt handler. If you're going to install your own ExternEnt handler, then you should set (or unset) this handler too. Entity (Expat, 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 (Expat, 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::Content object. See `"XML::Parser::ContentModel Methods"', *Note XML/Parser/Expat: XML/Parser/Expat, for methods available for this class. Attlist (Expat, 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 (Expat, 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 is the internal subset, given as a string. If there was no internal subset, it will be undefined. Internal will contain all whitespace, comments, processing instructions, and declarations seen in the internal subset. The declarations will be there whether or not they have been processed by another handler (except for unparsed entities processed by the Unparsed handler). However, comments and processing instructions will not appear if they've been processed by their respective handlers. * DoctypeFin (Parser) ---------------------- This handler is called after parsing of the DOCTYPE declaration has finished, including any internal or external DTD declarations. XMLDecl (Expat, Version, Encoding, Standalone) ----------------------------------------------- This handler is called for xml declarations. Version is a string containg the version. Encoding is either undefined or contains an encoding string. Standalone will be either true, false, or undefined if the standalone attribute is yes, no, or not made respectively. STYLES ====== Debug ----- This just prints out the document in outline form. Nothing special is returned by parse. Subs ---- Each time an element starts, a sub by that name in the package specified by the Pkg option is called with the same parameters that the Start handler gets called with. Each time an element ends, a sub with that name appended with an underscore ("_"), is called with the same parameters that the End handler gets called with. Nothing special is returned by parse. Tree ---- Parse will return a parse tree for the document. Each node in the tree takes the form of a tag, content pair. Text nodes are represented with a pseudo-tag of "0" and the string that is their content. For elements, the content is an array reference. The first item in the array is a (possibly empty) hash reference containing attributes. The remainder of the array is a sequence of tag-content pairs representing the content of the element. So for example the result of parsing: Hello thereHowdydo would be: Tag Content ================================================================== [foo, [{}, head, [{id => "a"}, 0, "Hello ", em, [{}, 0, "there"]], bar, [ {}, 0, "Howdy", ref, [{}]], 0, "do" ] ] The root document "foo", has 3 children: a "head" element, a "bar" element and the text "do". After the empty attribute hash, these are represented in it's contents by 3 tag-content pairs. Objects ------- This is similar to the Tree style, except that a hash object is created for each element. The corresponding object will be in the class whose name is created by appending "::" and the element name to the package set with the Pkg option. Non-markup text will be in the ::Characters class. The contents of the corresponding object will be in an anonymous array that is the value of the Kids property for that object. Stream ------ This style also uses the Pkg package. If none of the subs that this style looks for is there, then the effect of parsing with this style is to print a canonical copy of the document without comments or declarations. All the subs receive as their 1st parameter the Expat instance for the document they're parsing. It looks for the following routines: * StartDocument Called at the start of the parse . * StartTag Called for every start tag with a second parameter of the element type. The $_ variable will contain a copy of the tag and the %_ variable will contain attribute values supplied for that element. * EndTag Called for every end tag with a second parameter of the element type. The $_ variable will contain a copy of the end tag. * Text Called just before start or end tags with accumulated non-markup text in the $_ variable. * PI Called for processing instructions. The $_ variable will contain a copy of the PI and the target and data are sent as 2nd and 3rd parameters respectively. * EndDocument Called at conclusion of the parse. ENCODINGS ========= XML documents may be encoded in character sets other than Unicode as long as they may be mapped into the Unicode character set. Expat has further restrictions on encodings. Read the xmlparse.h header file in the expat distribution to see details on these restrictions. Expat has built-in encodings for: `UTF-8', `ISO-8859-1', `UTF-16', and `US-ASCII'. Encodings are set either through the XML declaration encoding attribute or through the ProtocolEncoding option to XML::Parser or XML::Parser::Expat. For encodings other than the built-ins, expat calls the function load_encoding in the Expat package with the encoding name. This function looks for a file in the path list @XML::Parser::Expat::Encoding_Path, that matches the lower-cased name with a '.enc' extension. The first one it finds, it loads. If you wish to build your own encoding maps, check out the XML::Encoding module from CPAN. AUTHORS ======= Larry Wall <`larry@wall.org'> wrote version 1.0. Clark Cooper <`coopercc@netheaven.com'> picked up support, changed the API for this version (2.x), provided documentation, and added some standard package features.  File: pm.info, Node: XML/Parser/EasyTree, Next: XML/Parser/Expat, Prev: XML/Parser, Up: Module List Easier tree style for XML::Parser ********************************* NAME ==== XML::Parser::EasyTree - Easier tree style for XML::Parser SYNOPSIS ======== use XML::Parser; use XML::Parser::EasyTree; $XML::Parser::Easytree::Noempty=1; my $p=new XML::Parser(Style=>'EasyTree'); my $tree=$p->parsefile('something.xml'); DESCRIPTION =========== XML::Parser::EasyTree adds a new "built-in" style called "EasyTree" to XML::Parser. Like XML::Parser's "Tree" style, setting this style causes the parser to build a lightweight tree structure representing the XML document. This structure is, at least in this author's opinion, easier to work with than the one created by the built-in style. When the parser is invoked with the EasyTree style, it returns a reference to an array of tree nodes, each of which is a hash reference. All nodes have a 'type' key whose value is the type of the node: 'e' for element nodes, 't' for text nodes, and 'p' for processing instruction nodes. All nodes also have a 'content' key whose value is a reference to an array holding the element's child nodes for element nodes, the string value for text nodes, and the data value for processing instruction nodes. Element nodes also have an 'attrib' key whose value is a reference to a hash of attribute names and values. Processing instructions also have a 'target' key whose value is the PI's target. EasyTree nodes are ordinary Perl hashes and are not objects. Contiguous runs of text are always returned in a single node. The reason the parser returns an array reference rather than the root element's node is that an XML document can legally contain processing instructions outside the root element (the xml-stylesheet PI is commonly used this way). If the parser's Namespaces option is set, element and attribute names will be prefixed with their (possibly empty) namespace URI enclosed in curly brackets. SPECIAL VARIABLES ================= Two package global variables control special behaviors: XML::Parser::EasyTree::Latin If this is set to a nonzero value, all text, names, and values will be returned in ISO-8859-1 (Latin-1) encoding rather than UTF-8. XML::Parser::EasyTree::Noempty If this is set to a nonzero value, text nodes containing nothing but whitespace (such as those generated by line breaks and indentation between tags) will be omitted from the parse tree. EXAMPLE ======= Parse a prettyprined version of the XML shown in the example for the built-in "Tree" style: #!perl -w use strict; use XML::Parser; use XML::Parser::EasyTree; use Data::Dumper; $XML::Parser::EasyTree::Noempty=1; my $xml=<<'EOF'; Hello there Howdy do EOF my $p=new XML::Parser(Style=>'EasyTree'); my $tree=$p->parse($xml); print Dumper($tree); Returns: $VAR1 = [ { 'name' => 'foo', 'type' => 'e', 'content' => [ { 'name' => 'head', 'type' => 'e', 'content' => [ { 'type' => 't', 'content' => 'Hello ' }, { 'name' => 'em', 'type' => 'e', 'content' => [ { 'type' => 't', 'content' => 'there' } ], 'attrib' => {} } ], 'attrib' => { 'id' => 'a' } }, { 'name' => 'bar', 'type' => 'e', 'content' => [ { 'type' => 't', 'content' => 'Howdy' }, { 'name' => 'ref', 'type' => 'e', 'content' => [], 'attrib' => {} } ], 'attrib' => {} }, { 'type' => 't', 'content' => ' do ' } ], 'attrib' => {} } ]; AUTHOR ====== Eric Bohlman (ebohlman@omsdev.com) Copyright (c) 2001 Eric Bohlman. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. SEE ALSO ======== XML::Parser  File: pm.info, Node: XML/Parser/Expat, Next: XML/Parser/PerlSAX, Prev: XML/Parser/EasyTree, Up: Module List Lowlevel access to James Clark's expat XML parser ************************************************* NAME ==== XML::Parser::Expat - Lowlevel access to James Clark's expat XML parser SYNOPSIS ======== use XML::Parser::Expat; $parser = new XML::Parser::Expat; $parser->setHandlers('Start' => \&sh, 'End' => \&eh, 'Char' => \&ch); open(FOO, 'info.xml') or die "Couldn't open"; $parser->parse(*FOO); close(FOO); # $parser->parse(' here we go '); sub sh { my ($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"' in this node method and two names can be checked for absolute equality with the `"eq_name"' in this node 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 () 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"' in this node 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 containg 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 elsewere (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 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 automaticly 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@wall.org'> wrote version 1.0. Clark Cooper <`coopercc@netheaven.com'> picked up support, changed the API for this version (2.x), provided documentation, and added some standard package features.