1XML::Smart::FAQ(3)    User Contributed Perl Documentation   XML::Smart::FAQ(3)
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NAME

6       XML::Smart::FAQ - Frequently Asked Questions about XML::Smart.
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SYNOPSIS

9       This is the Frequently Asked Questions list for XML::Smart.
10

QUESTIONS

12       For new questions send an e-mail to the author, but please, read first
13       all the F.A.Q.
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15   Do I need to install XML::Parser to can use XML::Smart?
16       No! XML::Smart already comes with 2 independent parsers,
17       XML::Smart::Parser and XML::Smart::HTMLParser.
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19       If XML::Parser is found XML::Smart will use it by default, and the 2nd
20       options will be XML::Smart::Parser.
21
22       Note that for complex parsing XML::Parser is recommended, but
23       XML::Smart::Parser will work fine too.
24
25   What is the best version of XML::Smart to install?
26       Is always the last! Always take a look for new versions before aks for
27       help on XML::Smart.
28
29       Note that internally XML::Smart is complex, since the main idea of it
30       is to remove the complexity from the hand of the programmer.  Actually
31       the idea is to enable the Perl programmer to use and create XML data
32       without really know the XML format.
33
34   Where can I learn about XML?
35       http://www.xml.com
36
37   How to apply a DTD to a XML::Smart object tree?
38       Take a look in the method apply_dtd(). Example of use:
39
40         $xml->apply_dtd(q`
41         <!DOCTYPE cds [
42         <!ELEMENT cds (album+)>
43         <!ATTLIST cds
44                   creator  CDATA
45                   date     CDATA #REQUIRED
46         >
47         <!ELEMENT album (artist , tracks+)>
48         <!ELEMENT artist (#PCDATA)>
49         <!ELEMENT tracks (#PCDATA)>
50         ]>
51         `);
52
53       This will format automatically elements, attributes, etc...
54
55   How XML::Smart works?
56       To create XML::Smart, first I have created the module
57       Object::MultiType.  With it you can have an object that works at the
58       same time as a HASH, ARRAY, SCALAR, CODE & GLOB. So you can do things
59       like this with the same object:
60
61         $obj = Object::MultiType->new() ;
62
63         $obj->{key} ;
64         $obj->[0] ;
65         $obj->method ;
66
67         @l = @{$obj} ;
68         %h = %{$obj} ;
69
70         &$obj(args) ;
71
72         print $obj "send data\n" ;
73
74       Seems to be crazy, and can be more if you use tie() inside it, and this
75       is what XML::Smart does.
76
77       For XML::Smart, the access in the Hash and Array way paste through
78       tie(). In other words, you have a tied HASH and tied ARRAY inside it.
79       This tied Hash and Array work together, soo you can access a Hash key
80       as the index 0 of an Array, or access an index 0 as the Hash key:
81
82         %hash = (
83         key => ['a','b','c']
84         ) ;
85
86         $hash->{key}    ## return $hash{key}[0]
87         $hash->{key}[0] ## return $hash{key}[0]
88         $hash->{key}[1] ## return $hash{key}[1]
89
90         ## Inverse:
91
92         %hash = ( key => 'a' ) ;
93
94         $hash->{key}    ## return $hash{key}
95         $hash->{key}[0] ## return $hash{key}
96         $hash->{key}[1] ## return undef
97
98       The best thing of this new resource is to avoid wrong access to the
99       data and warnings when you try to access a Hash having an Array (and
100       the inverse). Thing that generally make the script die().
101
102       Once having an easy access to the data, you can use the same resource
103       to create data!  For example:
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105         ## Previous data:
106         <hosts>
107           <server address="192.168.2.100" os="linux" type="conectiva" version="9.0"/>
108         </hosts>
109
110         ## Now you have {address} as a normal key with a string inside:
111         $XML->{hosts}{server}{address}
112
113         ## And to add a new address, the key {address} need to be an ARRAY ref!
114         ## So, XML::Smart make the convertion: ;-P
115         $XML->{hosts}{server}{address}[1] = '192.168.2.101' ;
116
117         ## Adding to a list that you don't know the size:
118         push(@{$XML->{hosts}{server}{address}} , '192.168.2.102') ;
119
120         ## The data now:
121         <hosts>
122           <server os="linux" type="conectiva" version="9.0"/>
123             <address>192.168.2.100</address>
124             <address>192.168.2.101</address>
125             <address>192.168.2.102</address>
126           </server>
127         </hosts>
128
129       Than after changing your XML tree using the Hash and Array resources
130       you just get the data remade (through the Hash tree inside the object):
131
132         my $xmldata = $XML->data ;
133
134       But note that XML::Smart always return an object! Even when you get a
135       final key. So this actually returns another object, pointhing (inside
136       it) to the key:
137
138         $addr = $XML->{hosts}{server}{address}[0] ;
139
140         ## Since $addr is an object you can TRY to access more data:
141         $addr->{foo}{bar} ; ## This doens't make warnings! just return UNDEF.
142
143         ## But you can use it like a normal SCALAR too:
144
145         print "$addr\n" ;
146
147         $addr .= ':80' ; ## After this $addr isn't an object any more, just a SCALAR!
148
149   When I generate the XML data new lines (\n) are added to the content!
150       You should use the options for the method data() and save() to not add
151       identation to the generated data:
152
153         $XML->data( noident => 1 ) ;
154
155         ## or better:
156
157         $XML->data( nospace => 1 ) ;
158
159   Your question is not here?
160       Just send me an e-mail. ;-P
161

AUTHOR

163       Graciliano M. P. <gm@virtuasites.com.br>
164
165       I will appreciate any type of feedback (include your opinions and/or
166       suggestions). ;-P
167
168       Enjoy and thanks for who are enjoying this tool and have sent e-mails!
169       ;-P
170

ePod

172       This document was written in ePod (easy-POD), than converted to POD,
173       and from here you know the way.
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177perl v5.34.0                      2021-07-23                XML::Smart::FAQ(3)