1SVG::Parser(3) User Contributed Perl Documentation SVG::Parser(3)
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6 SVG::Parser - XML Parser for SVG documents
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9 #!/usr/bin/perl -w
10 use strict;
11 use SVG::Parser;
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13 die "Usage: $0 <file>\n" unless @ARGV;
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15 my $xml;
16 {
17 local $/=undef;
18 $xml=<>;
19 }
20
21 my $parser=new SVG::Parser(-debug => 1);
22 my $svg=$parser->parse($xml);
23 print $svg->xmlify;
24
25 and:
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27 #!/usr/bin/perl -w
28 use strict;
29 use SVG::Parser qw(SAX=XML::LibXML::Parser::SAX Expat SAX);
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31 die "Usage: $0 <file>\n" unless @ARGV;
32 my $svg=SVG::Parser->new()->parsefile($ARGV[0]);
33 print $svg->xmlify;
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36 SVG::Parser is an XML parser for SVG Documents. It takes XML as input
37 and produces an SVG object as its output.
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39 SVG::Parser supports both XML::SAX and XML::Parser (Expat) parsers,
40 with SAX preferred by default. Only one of these needs to be installed
41 for SVG::Parser to function.
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43 A list of preferred parsers may be specified in the import list -
44 SVG::Parser will use the first parser that successfully loads. Some
45 basic measures are taken to provide cross-compatability. Applications
46 requiring more advanced parser features should use the relevant parser
47 module directly; see SVG::Parser::Expat and SVG::Parser::SAX.
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49 METHODS
50 SVG::Parser provides all methods supported by its parent parser class.
51 In addition it provides the following:
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53 • new([%attrs])
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55 Create a new SVG::Parser object. Optional attributes may be passed
56 as arguments; all attributes without a leading '-' prefix are
57 passed to the parent constructor. For example:
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59 my $parser=new SVG::Parser(%parser_options);
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61 Note that parser options are dependant on which parser type is
62 selected.
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64 Attributes with a leading '-' are processed by SVG::Parser.
65 Currently the only recognised attribute is '-debug', which
66 generates a simple but possibly useful debug trace of the parsing
67 process to standard error. For example:
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69 my $parser=new SVG::Parser(-debug => 1);
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71 or:
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73 my $parser=SVG::Parser->new(-debug => 1);
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75 Attributes with a leading '--' are passed to the SVG constructor
76 when creating the SVG object returned as the result of the parse:
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78 my $parser=new SVG::Parser(
79 -debug => 1,
80 "--indent" => "\t",
81 "--raiseerror" => 1
82 );
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84 The leading '-' is stripped from attribute names passed this way,
85 so this sets the '-indent' and '-raiseerror' attributes in the SVG
86 module. See SVG for a list of valid SVG options.
87
88 (The "new" constructor is provided by XML::SAX::Expat or
89 SVG::Parser::SAX, but operates identically in either case.)
90
91 • parse($xml)
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93 Parse an XML document and return an SVG object which may then be
94 used to manipulate the SVG content before regenerating the output
95 XML. For example:
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97 my $svg=$parser->parse($svgxml);
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99 Because the parse() method differs in use beteen XML::Parser and
100 XML::SAX, SVG::Parser provides its own parse() method. This calls
101 the parent parser with the correct first argument when given either
102 a filehandle or a string as input.
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104 Additional arguments are passed to the parent parser class, but
105 since XML::Parser and XML::SAX parsers take options in different
106 formats this is of limited use. SVG::Parser does not currently
107 provide any translation of parser options.
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109 See XML::Parser, XML::SAX, and XML::Parser::PerlSAX for other ways
110 to parse input XML.
111
112 • parse_file($filehandle|$filename)
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114 • parsefile($filehandle|$filename)
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116 Since the parse_file() method (XML::SAX) and parsefile() method
117 (XML::Parser) differ in both name and usage, SVG::Parser provides
118 its own version of both methods that determines whether the passed
119 argument is a filehandle or a file name and directs the call to the
120 appropriate parent parser method.
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122 Both methods will work equally well whichever parent parser class
123 is in use:
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125 my $svg=$parser->parse_file($svgxml);
126 my $svg=$parser->parsefile($svgxml);
127 my $svg=$parser->parse_file(*SVGIN);
128 my $svg=$parser->parsefile(*SVGIN);
129 ...etc...
130
131 (These methods will also work when using SVG::Parser::Expat or
132 SVG::Parser::SAX directly.)
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134 EXPORTS
135 None. However, a list of preferred parsers can be specified by passing
136 the package name to SVG::Parser in the import list. This allows an SVG
137 parser application to use the best parser available without knowing
138 what XML parsers might be available on the target platform. SAX is
139 generally preferred to Expat, but an Expat-based parser may be
140 preferable to the slow Perl-based SAX parser XML::SAX::PurePerl. (See
141 XML::SAX::PurePerl.)
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143 Each parser specification consists of one of the two supported SVG
144 parsers, SVG::Parser::Expat or SVG::Parser::SAX, optionally followed by
145 an '=' and an explicit parser package. For example:
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147 use SVG::Parser qw(SVG::Parser::SAX SVG::Parser::Expat);
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149 Instead of specifying the full SVG parser name, 'Expat' and 'SAX' may
150 be used as shorthand. For example:
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152 use SVG::Parser qw(SAX Expat);
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154 Both the above examples produce the default behaviour. To prefer Expat
155 over SAX use either of:
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157 use SVG::Parser qw(SVG::Parser::Expat SVG::Parser::SAX);
158 use SVG::Parser qw(Expat SAX);
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160 To use Expat with a specific XML::Parser subclass:
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162 use SVG::Parser qw(SVG::Parser::Expat=My::XML::Parser::Subclass);
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164 To use SAX with the XML::LibXML SAX parser:
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166 use SVG::Parser qw(SVG::Parser::SAX=XML::LibXML::SAX::Parser);
167
168 A number of specifications can be listed to have SVG::Parse try a
169 number of possible parser alternatives in decreasing order of
170 preference:
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172 use SVG::Parser qw(
173 SAX=My::SAXParser
174 Expat=My::Best::ExpatParser
175 SAX=XML::LibXML::SAX::Parser
176 Expat=My::Other::ExpatParser
177 Expat
178 SAX
179 )
180
181 You can test different scenarios from the command line. For example:
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183 perl -MSVG::Parser=SAX mysvgapp.pl
184 perl -MSVG::Parser=Expat,SAX mysvgapp.pl
185 perl -MSVG::Parser=SAX=XML::LibXML::SAX::Parser,Expat mysvgapp.pl
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187 To pass additional items in the import list to the parent Expat or SAX
188 parser class, use additional '=' separators in the parser
189 specification. In the case of XML::SAX a minimum version number may be
190 required this way:
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192 # require version 1.40+ of the LibXML SAX parser, otherwise use Perl
193 use SVG::Parser qw(
194 SAX=XML::LibXML::SAX::Parser=1.40
195 SAX=XML::SAX::PurePerl
196 );
197
198 Similarly, from the command line:
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200 perl -MSVG::Parser=SAX=XML::LibXML::SAX::Parser=1.40,SAX=XML::SAX::PurePerl mysvgapp.pl
201
202 EXAMPLES
203 See "svgparse", "svgparse2", and "svgparse3" in the examples directory
204 of the distribution, along with "svgexpatparse" and "svgsaxparse" for
205 examples of using the SVG::Parser::Expat and SVG::Parser::SAX modules
206 directly.
207
209 Peter Wainwright, peter.wainwright@cybrid.net
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212 SVG, SVG::Parser::Expat, SVG::Parser::SAX, XML::Parser, XML::SAX
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216perl v5.34.0 2021-07-22 SVG::Parser(3)