| SGML::Parser::OpenSP(3pm) | User Contributed Perl Documentation | SGML::Parser::OpenSP(3pm) |
SGML::Parser::OpenSP - Parse SGML documents using OpenSP
use SGML::Parser::OpenSP;
my $p = SGML::Parser::OpenSP->new;
my $h = ExampleHandler->new;
$p->catalogs(qw(xhtml.soc));
$p->warnings(qw(xml valid));
$p->handler($h);
$p->parse("example.xhtml");
This module provides an interface to the OpenSP SGML parser. OpenSP and this module are event based. As the parser recognizes parts of the document (say the start or end of an element), then any handlers registered for that type of an event are called with suitable parameters.
The default is true except on platforms, such as Win32, which are known to not support passing file descriptors around in this manner. On platforms which support it you can call this method with a false parameter to force use of temporary file names instead.
In general, this will do the right thing on its own so it's best to consider this an internal method. If your platform is such that you have to force use of the OSFILE storage manager, please report it as a bug and include the values of $^O, $Config{archname}, and a description of the platform (e.g. "Windows Vista Service Pack 42").
<!ENTITY % name "INCLUDE">
occurs at the start of the document type declaration subset in the SGML document entity. Since repeated definitions of an entity are ignored, this definition will take precedence over any other definitions of this entity in the document type declaration. Multiple names are allowed. If the SGML declaration replaces the reserved name INCLUDE then the new reserved name will be the replacement text of the entity. Typically the document type declaration will contain
<!ENTITY % name "IGNORE">
and will use %name; in the status keyword specification of a marked section declaration. In this case the effect of the option will be to cause the marked section not to be ignored.
Additional warnings can be enabled using
$p->warnings([@warnings])
The following values can be used to enable warnings:
A warning can be disabled by using its name prefixed with "no-". Thus calling warnings(qw(all no-duplicate)) will enable all warnings except those about duplicate entity declarations.
The following values for warnings() disable errors:
The following warnings are turned on for the "xml" warning described above:
In order to start processing of a document and receive events, the "parse" method must be called. It takes one argument specifying the path to a file (not a file handle). You must set an event handler using the "handler" method prior to using this method. The return value of "parse" is currently undefined.
In order to receive data from the parser you need to write an event handler. For example,
package ExampleHandler;
sub new { bless {}, shift }
sub start_element
{
my ($self, $elem) = @_;
printf " * %s\n", $elem->{Name};
}
This handler would print all the element names as they are found in the document, for a typical XHTML document this might result in something like
* html * head * title * body * p * ...
The events closely match those in the generic interface to OpenSP, see <http://openjade.sf.net/doc/generic.htm> for more information.
The event names have been changed to lowercase and underscores to separate words and properties are capitalized. Arrays are represented as Perl array references. "Position" information is not passed to the handler but made available through the "get_location" method which can be called from event handlers. Some redundant information has also been stripped and the generic identifier of an element is stored in the "Name" hash entry.
For example, for an EndElementEvent the "end_element" handler gets called with a hash reference
{
Name => 'gi'
}
The following events are defined:
* appinfo * processing_instruction * start_element * end_element * data * sdata * external_data_entity_ref * subdoc_entity_ref * start_dtd * end_dtd * end_prolog * general_entity # set $p->output_general_entities(1) * comment_decl # set $p->output_comment_decls(1) * marked_section_start # set $p->output_marked_sections(1) * marked_section_end # set $p->output_marked_sections(1) * ignored_chars # set $p->output_marked_sections(1) * error * open_entity_change
If the documentation of the generic interface to OpenSP states that certain data is not valid, it will not be available through this interface (i.e., the respective key does not exist in the hash ref).
Event handlers can call the "get_location" method on the parser object to retrieve positioning information, the get_location method will return a hash reference with the following properties:
LineNumber => ..., # line number ColumnNumber => ..., # column number ByteOffset => ..., # number of preceding bytes EntityOffset => ..., # number of preceding bit combinations EntityName => ..., # name of the external entity FileName => ..., # name of the file
These can be "undef" or an empty string.
OpenSP returns error messages in form of a string rather than individual components of the message like line numbers or message text. The "split_message" method on the parser object can be used to post-process these error message strings as reliable as possible. It can be used e.g. from an error event handler if the parser object is accessible like
sub error
{
my $self = shift;
my $erro = shift;
my $mess = $self->{parser}->split_message($erro);
}
See the documentation of "split_message" in the SGML::Parser::OpenSP::Tools documentation.
All strings returned from event handlers and helper routines are UTF-8 encoded with the UTF-8 flag turned on, helper functions like "split_message" expect (but don't check) that string arguments are UTF-8 encoded and have the UTF-8 flag turned on. Behavior of helper functions is undefined when you pass unexpected input and should be avoided.
"parse" has limited support for binary input, but the binary input must be compatible with OpenSP's generic interface requirements and you must specify the encoding through means available to OpenSP to enable it to properly decode the binary input. Any encoding meta data about such binary input specific to Perl (such as encoding disciplines for file handles when you pass a file descriptor) will be ignored. For more specific information refer to the OpenSP manual.
OpenSP supports a number of environment variables to control specific processing aspects such as "SGML_SEARCH_PATH" or "SP_CHARSET_FIXED". Portable applications need to ensure that these are set prior to loading the OpenSP library into memory which happens when the XS code is loaded. This means you need to wrap the code into a "BEGIN" block:
BEGIN { $ENV{SP_CHARSET_FIXED} = 1; }
use SGML::Parser::OpenSP;
# ...
Otherwise changes to the environment might not propagate to OpenSP. This applies specifically to Win32 systems.
Note that you can use the "search_dirs" method instead of using "SGML_SEARCH_PATH" and the "catalogs" method instead of using "SGML_CATALOG_FILES" and attributes on storage object specifications for "SP_BCTF" and "SP_ENCODING" respectively. For example, if "SP_CHARSET_FIXED" is set to 1 you can use
$p->parse("<OSFILE encoding='UTF-8'>example.xhtml");
to process "example.xhtml" using the "UTF-8" character encoding.
OpenSP must be compiled with "SP_MULTI_BYTE" defined and with "SP_WIDE_SYSTEM" undefined, this module will otherwise break at runtime or not compile.
Please report bugs in this module via <http://rt.cpan.org/NoAuth/Bugs.html?Dist=SGML-Parser-OpenSP>
Please report bugs in OpenSP via <http://sf.net/tracker/?group_id=2115&atid=102115>
Please send comments and questions to the spo-devel mailing list, see <http://lists.sf.net/lists/listinfo/spo-devel> for details.
Terje Bless <link@cpan.org> wrote version 0.01. Bjoern Hoehrmann <bjoern@hoehrmann.de> wrote version 0.02+.
Copyright (c) 2006-2008 Bjoern Hoehrmann <bjoern@hoehrmann.de>. This module is licensed under the same terms as Perl itself.
| 2024-03-31 | perl v5.38.2 |