Boulder::XML(3pm)

1Boulder::XML(3)       User Contributed Perl Documentation      Boulder::XML(3)
2
3
4

NAME

6       Boulder::XML - XML format input/output for Boulder streams
7

SYNOPSIS

9          use Boulder::XML;
10
11          $stream = Boulder::XML->newFh;
12
13          while ($stone = <$stream>) {
14               print $stream $stone;
15          }
16

DESCRIPTION

18       Boulder::XML generates BoulderIO streams from XML files and/or streams.
19       It is also able to output Boulder Stones in XML format.  Its semantics
20       are similar to those of Boulder::Stream, except that there is never any
21       pass-through behavior.
22
23       Because XML was not designed for streaming, some care must be taken
24       when reading an XML document into a series of Stones.  Consider this
25       XML document:
26
27        <?xml version="1.0" standalone="yes"?>
28
29        <Paper>
30          <Author>Lincoln Stein</Author>
31          <Author>Jean Siao</Author>
32          <Date>September 29, 1999</Date>
33          <Copyright copyrighted="yes">1999 Lincoln Stein</Copright>
34          <Abstract>
35              This is the abstract.  It is not anything very fancy,
36              but it will do.
37          </Abstract>
38          <Citation>
39               <Author>Fitchberg J</Author>
40               <Journal>Journal of Irreproducible Results</Journal>
41               <Volume>23</Volume>
42               <Year>1998</Volume>
43          </Citation>
44          <Citation>
45               <Author>Clemenson V</Author>
46               <Journal>Ecumenica</Journal>
47               <Volume>10</Volume>
48               <Year>1968</Volume>
49          </Citation>
50          <Citation>
51               <Author>Ruggles M</Author>
52               <Journal>Journal of Aesthetic Surgery</Journal>
53               <Volume>10</Volume>
54               <Year>1999</Volume>
55          </Citation>
56        </Paper>
57
58       Ordinarily the document will be construed as a single Paper tag
59       containing subtags Author, Date, Copyright, Abstract, and so on.
60       However it might be desirable to fetch out just the citation tags as a
61       series of Stones.  In this case, you can declare Citation to be the top
62       level tag by passing the -tag argument to new(). Now calling get() will
63       return each of the three Citation sections in turn.  If no tag is
64       explicitly declared to be the top level tag, then Boulder::XML will
65       take the first tag it sees in the document.
66
67       It is possible to stream XML files.  You can either separate them into
68       separate documents and use the automatic ARGV processing features of
69       the BoulderIO library, or separate the XML documents using a delimiter
70       string similar to the delimiters used in MIME multipart documents.  By
71       default, BoulderIO uses a delimiter of <!--Boulder::XML-->.
72
73       This is not a general XML parsing engine! Instead, it is a way to
74       represent BoulderIO tag/value streams in XML format.  The module uses
75       XML::Parser to parse the XML streams, and therefore any syntactic error
76       in the stream can cause the XML parser to quit with an error.  Another
77       thing to be aware of is that there are certain XML constructions that
78       will not translate into BoulderIO format, specifically free text that
79       contains embedded tags.  This is OK:
80
81         <Author>Jean Siao</Author>
82
83       but this is not:
84
85         <Author>The <Emphatic>extremely illustrious</Emphatic> Jean Siao</Author>
86
87       In BoulderIO format, tags can contain other tags or text, but cannot
88       contain a mixture of tags and text.
89
90   CONSTRUCTORS
91       $stream = Boulder::XML->new(*IN,*OUT);
92       $stream =
93       Boulder::XML->new(-in=>*IN,-out=>*OUT,-tag=>$tag,-delim=>$delim,-strip=>$strip)
94           new() creates a new Boulder::XML stream that can be read from or
95           written to.  All arguments are optional.
96
97            -in    Filehandle to read from.
98                   If a file name is provided, will open the file.
99                   Defaults to the magic <> filehandle.
100
101            -out   Filehandle to write to.
102                   If a file name is provided, will open the file for writing.
103                   Defaults to STDOUT
104
105            -tag   The top-level XML tag to consider as the Stone record.  Defaults
106                   to the first tag seen when reading from an XML file, or to
107                   E<lt>StoneE<gt> when writing to an output stream without
108                   previously having read.
109
110            -delim Delimiter to use for delimiting multiple Stone objects in an
111                   XML stream.
112
113            -strip If true, automatically strips leading and trailing whitespace
114                   from text contained within tags.
115
116       $fh = Boulder::XML->newFh(*IN,*OUT);
117       $fh =
118       Boulder::XML->newFh(-in=>*IN,-out=>*OUT,-tag=>$tag,-delim=>$delim,-strip=>$strip)
119           The newFh() constructor creates a tied filehandle that can read and
120           write Boulder::XML streams.  Invoking <> on the filehandle will
121           perform a get(), returning a Stone object.  Calling print() on the
122           filehandle will perform a put(), writing a Stone object to output
123           in XML format.
124
125   METHODS
126       $stone = $stream->get()
127       $stream->put($stone)
128       $done = $stream->done
129           All these methods have the same semantics as the similar methods in
130           Boulder::Stream, except that pass-through behavior doesn't apply.
131

AUTHOR

133       Lincoln D. Stein <lstein@cshl.org>, Cold Spring Harbor Laboratory, Cold
134       Spring Harbor, NY.  This module can be used and distributed on the same
135       terms as Perl itself.
136

NAME

SYNOPSIS

DESCRIPTION

AUTHOR

SEE ALSO