NAME¶
XML::Smart::FAQ - Frequently Asked Questions about XML::Smart.
SYNOPSIS¶
This is the Frequently Asked Questions list for XML::Smart.
QUESTIONS¶
For new questions send an e-mail to the author, but please, read first all
the F.A.Q.
Do I need to install XML::Parser to can use XML::Smart?¶
No! XML::Smart already comes with 2 independent parsers, XML::Smart::Parser and
XML::Smart::HTMLParser.
If XML::Parser is found XML::Smart will use it by default, and the 2nd options
will be XML::Smart::Parser.
Note that for complex parsing XML::Parser is recommended, but XML::Smart::Parser
will work fine too.
What is the best version of XML::Smart to install?¶
Is always the last! Always take a look for new versions before aks for help on
XML::Smart.
Note that internally XML::Smart is complex, since the main idea of it is to
remove the complexity from the hand of the programmer. Actually the idea is to
enable the Perl programmer to use and create XML data without really know the
XML format.
Where can I learn about XML?¶
http://www.xml.com
How to apply a DTD to a XML::Smart object tree?¶
Take a look in the method
apply_dtd(). Example of use:
$xml->apply_dtd(q`
<!DOCTYPE cds [
<!ELEMENT cds (album+)>
<!ATTLIST cds
creator CDATA
date CDATA #REQUIRED
>
<!ELEMENT album (artist , tracks+)>
<!ELEMENT artist (#PCDATA)>
<!ELEMENT tracks (#PCDATA)>
]>
`);
This will format automatically elements, attributes, etc...
How XML::Smart works?¶
To create
XML::Smart, first I have created the module Object::MultiType.
With it you can have an object that works at the same time as a HASH, ARRAY,
SCALAR, CODE & GLOB. So you can do things like this with the same object:
$obj = Object::MultiType->new() ;
$obj->{key} ;
$obj->[0] ;
$obj->method ;
@l = @{$obj} ;
%h = %{$obj} ;
&$obj(args) ;
print $obj "send data\n" ;
Seems to be crazy, and can be more if you use
tie() inside it, and this
is what
XML::Smart does.
For
XML::Smart, the access in the Hash and Array way paste through
tie(). In other words, you have a tied HASH and tied ARRAY inside it.
This tied Hash and Array work together, soo
you can access a Hash key
as the index 0 of an Array, or access an index 0 as the Hash key:
%hash = (
key => ['a','b','c']
) ;
$hash->{key} ## return $hash{key}[0]
$hash->{key}[0] ## return $hash{key}[0]
$hash->{key}[1] ## return $hash{key}[1]
## Inverse:
%hash = ( key => 'a' ) ;
$hash->{key} ## return $hash{key}
$hash->{key}[0] ## return $hash{key}
$hash->{key}[1] ## return undef
The best thing of this new resource is to avoid wrong access to the data and
warnings when you try to access a Hash having an Array (and the inverse).
Thing that generally make the script
die().
Once having an easy access to the data, you can use the same resource to
create data! For example:
## Previous data:
<hosts>
<server address="192.168.2.100" os="linux" type="conectiva" version="9.0"/>
</hosts>
## Now you have {address} as a normal key with a string inside:
$XML->{hosts}{server}{address}
## And to add a new address, the key {address} need to be an ARRAY ref!
## So, XML::Smart make the convertion: ;-P
$XML->{hosts}{server}{address}[1] = '192.168.2.101' ;
## Adding to a list that you don't know the size:
push(@{$XML->{hosts}{server}{address}} , '192.168.2.102') ;
## The data now:
<hosts>
<server os="linux" type="conectiva" version="9.0"/>
<address>192.168.2.100</address>
<address>192.168.2.101</address>
<address>192.168.2.102</address>
</server>
</hosts>
Than after changing your XML tree using the Hash and Array resources you just
get the data remade (through the Hash tree inside the object):
my $xmldata = $XML->data ;
But note that XML::Smart always return an object!
Even when you get a final key. So this actually returns another object,
pointhing (inside it) to the key:
$addr = $XML->{hosts}{server}{address}[0] ;
## Since $addr is an object you can TRY to access more data:
$addr->{foo}{bar} ; ## This doens't make warnings! just return UNDEF.
## But you can use it like a normal SCALAR too:
print "$addr\n" ;
$addr .= ':80' ; ## After this $addr isn't an object any more, just a SCALAR!
When I generate the XML data new lines (\n) are added to the content!¶
You should use the options for the method
data() and
save() to not
add identation to the generated data:
$XML->data( noident => 1 ) ;
## or better:
$XML->data( nospace => 1 ) ;
Your question is not here?¶
Just send me an e-mail. ;-P
AUTHOR¶
Graciliano M. P. <gm@virtuasites.com.br>
I will appreciate any type of feedback (include your opinions and/or
suggestions). ;-P
Enjoy and thanks for who are enjoying this tool and have sent e-mails! ;-P
ePod¶
This document was written in ePod (easy-POD), than converted to POD, and from
here you know the way.