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XML::DT.3pm
Langue: en
Version: 2004-01-22 (debian - 07/07/09)
Section: 3 (Bibliothèques de fonctions)
Sommaire
NAME
XML::DT - a package for down translation of XML filesSYNOPSIS
use XML::DT;%xml=( 'music' => sub{``Music from: $c\n''},
'lyrics' => sub{``Lyrics from: $v{name}\n''},
'title' => sub{ uc($c) },
'-default' => sub{``$q:$c''} );
print dt($filename,%xml);
ABSTRACT
This module is a XML down processor. It maps tag (element) names to functions to process that element and respective contents.DESCRIPTION
This module processes XML files with an approach similar to OMNIMARK. As XML parser it uses XML::Parser or XML::LibXML module in an independent way. At configure stage, you should choose one of the back-ends.If you use XML::LibXML module as backend, you can parse HTML files as if they were XML files. For this, you must supply an extra option to the hash:
%hander = ( -html => 1,
...
);
"dt" function
dt function
Down translation function "dt" receives a filename and a set of expressions (functions) defining the processing and associated values for each element.
"dtstring" function
dtstring function
"dtstring" works in a similar way with "dt" but takes input from a string instead of a file.
"dturl" function
dturl function
"dturl" works in a similar way with "dt" but takes input from an Internet url instead of a file.
"pathdt" function
pathdt function
The "pathdt" function is a "dt" function which can handle a subset of XPath on handler keys. Example:
%handler = ( ``article/title'' => sub{ toxml(``h1'',{},$c) }, ``section/title'' => sub{ toxml(``h2'',{},$c) }, ``title'' => sub{ $c }, ``//image[@type='jpg']'' => sub{ ``JPEG: <img src=\''$c\``>'' }, ``//image[@type='bmp']'' => sub{ ``BMP: sorry, no bitmaps on the web'' }, )
pathdt($filename,%handler);
Here are some examples of valid XPath expressions under XML::DT:
/aaa /aaa/bbb //ccc - ccc somewhere (same as ``ccc'') /*/aaa/* //* - same as ``-default'' /aaa[@id] - aaa with an attribute id /*[@*] - root with an attribute /aaa[not(@name)] - aaa with no attribute ``name'' //bbb[@name='foo'] - ... attribute ``name'' = ``foo'' /ccc[normalize-space(@name)='bbb'] //*[name()='bbb'] - complex way of saying ``//bbb'' //*[starts-with(name(),'aa')] - an element named ``aa.*'' //*[contains(name(),'c')] - an element ``.*c.*'' //aaa[string-length(name())=4] ``....'' //aaa[string-length(name())<4] ``.{1,4}'' //aaa[string-length(name())>5] ``.{5,}''
Note that not all XPath is currently handled by XML::DT. A lot of XPath will never be added to XML::DT because is not in accordance with the down translation model. For more documentation about XPath check the specification at http://www.w3c.org or some tutorials under http://www.zvon.org
"pathdtstring" function
pathdtstring function
Like the "dtstring" function but supporting XPath.
"pathdturl" function
pathdturl function
Like the "dturl" function but supporting XPath.
"inctxt" function
inctxt function
"inctxt(pattern)" is true if the actual element path matches the provided pattern. This function is meant to be used in the element functions in order to achieve context dependent processing.
"toxml" function
toxml function
This is the default ``-default'' function. It can be used to generate XML based on $c $q and %v variables. Example: add a new attribute to element "ele1" without changing it:
%handler=( ...
ele1 => sub { $v{at1} = ``v1''; toxml(); },
)
"toxml" can also be used with 3 arguments: tag, attributes and contents
toxml(``a'',{href=> ``http://local/f.html''}, ``example'')
returns:
<a href='http://local/f.html'>example</a>
"xmltree" function
xmltree function
This simple function just makes a HASH reference:
{ -c => $c, -q => $q, all_the_other_attributes }
The function "toxml" understands this structure and makes XML with it.
User provided element processing functions
The user must provide an HASH with a function for each element, that computes element output. Functions can use the element name $q, the element content $c and the attribute values hash %v.All those global variables are defined in $CALLER::.
Each time an element is find the associated function is called.
Content is calculated by concatenation of element contents strings and interior elements return values.
"-default" function
-default function
When a element has no associated function, the function associated with "-default" called. If no "-default" function is defined the default function returns a XML like string for the element.
When you use "/-type" definitions, you often need do set "-default" function to return just the contents: "sub{$id}".
"-outputenc" option
-outputenc option
"-outputenc" defines the output encoding (default is Unicode UTF8).
"-inputenc" option
-inputenc option
"-inputenc" forces a input encoding type. Whenever that is possible, define the input encoding in the XML file:
<?xml version='1.0' encoding='ISO-8859-1'?>
"-pcdata" function
-pcdata function
"-pcdata" function is used to define transformation over the contents. Typically this function should look at context (see "inctxt" function)
The default "-pcdata" function is the identity
"-begin" function
-begin function
Function to be executed before processing XML file.
Example of use: initialization of side-effect variables
"-end" function
-end function
Function to be executed after processing XML file. I can use $c content value. The value returned by "-end" will be the "dt" return value.
Example of use: post-processing of returned contents
Elements with values other than strings (-type)
By default all elements return strings, and contents ($c) is the concatenation of the strings returned by the sub-elements.In some situations the XML text contains values that are better processed as a structured type.
The following types (functors) are available:
- STR
- concatenates all the sub-elements returned values (DEFAULT) all the sub-element should return strings to be concatenated;
- SEQ
- makes an ARRAY with all the sub elements contents; attributes are ignored (they should be processed in the sub-element). (returns a ref) If you have different types of sub-elements, you should use SEQH
- SEQH
- makes an ARRAY of HASH with all the sub elements (returns a ref); for each sub-element:
-q => element name -c => contents at1 => at value1 for each attribute
- MAP
- makes an HASH with the sub elements; keys are the sub-element names, values are their contents. Attributes are ignored. (they should be processed in the sub-element) (returns a ref)
- MULTIMAP
- makes an HASH of ARRAY; keys are the sub-element names; values are lists of contents; attributes are ignored (they should be processed in the sub-element); (returns a ref)
- MMAPON(element-list)
- makes an HASH with the sub-elements; keys are the sub-element names, values are their contents; attributes are ignored (they should be processed in the sub-element); for all the elements contained in the element-list, it is created an ARRAY with their contents. (returns a ref)
- XML
- return a reference to an HASH with:
-q => element name -c => contents at1 => at value1 for each attribute
- ZERO
- don't process the sub-elements; return ""
When you use "/-type" definitions, you often need do set "-default" function returning just the contents "sub{$id}".
An example:
use XML::DT; %handler = ( contacts => sub{ [ split(``;'',$c)] }, -default => sub{$c},
-type => { institution => 'MAP',
degrees => MMAPON('name')
tels => 'SEQ' }
); $a = dt (``f.xml'', %handler);
with the following f.xml
<degrees> <institution> <id>U.M.</id> <name>University of Minho</name> <tels> <item>1111</item> <item>1112</item> <item>1113</item> </tels> <where>Portugal</where> <contacts>J.Joao; J.Rocha; J.Ramalho</contacts> </institution> <name>Computer science</name> <name>Informatica </name> <name> history </name> </degrees>
would make $a
{ 'name' => [ 'Computer science', 'Informatica ',
' history ' ],
'institution' => { 'tels' => [ 1111, 1112,
1113 ],
'name' => 'University of Minho',
'where' => 'Portugal',
'id' => 'U.M.',
'contacts' => [ 'J.Joao',
' J.Rocha',
' J.Ramalho' ] } };
DT Skeleton generation
It is possible to build an initial processor program based on an exampleTo do this use the function "mkdtskel(filename)".
Example:
perl -MXML::DT -e 'mkdtskel ``f.xml''' > f.pl
DTD skeleton generation
It makes a naive DTD based on an example(s).To do this use the function "mkdtdskel(filename*)".
Example:
perl -MXML::DT -e 'mkdtdskel ``f.xml''' > f.dtd
SEE ALSO
mkdtskel(1) and mkdtdskel(1)AUTHORS
Home for XML::DT;http://natura.di.uminho.pt/~jj/perl/XML/
Jose Joao Almeida, <jj@di.uminho.pt>
Alberto Manuel Simões, <albie@alfarrabio.di.uminho.pt>
thanks to
Michel Rodriguez <mrodrigu@ieee.org> José Carlos Ramalho <jcr@di.uminho.pt> Mark A. Hillebrand
Contenus ©2006-2024 Benjamin Poulain
Design ©2006-2024 Maxime Vantorre