Links: Next Previous Up Top

What are the generic events?

sgmlspl recognises the twelve generic events listed in table 1. You may provide any one of these as the first argument to sgml to declare a handler (string or subroutine) for that event.

Table 1: `sgmlspl` generic events

Event: 'start'
Description: Execute handler (with no arguments) at the beginning of the parse.

Event: 'end'
Description: Execute handler (with no arguments) at the end of the parse.

Event: 'start_element'
Description: Execute handler at the beginning of every element without a specific start handler.

Event: 'end_element'
Description: Execute handler at the end of every element without a specific end handler.

Event: 'cdata'
Description: Execute handler for every character-data string.

Event: 'sdata'
Description: Execute handler for every special-data string without a specific handler.

Event: 're'
Description: Execute handler for every record end.

Event: 'pi'
Description: Execute handler for every processing instruction.

Event: 'entity'
Description: Execute handler for every external data entity without a specific handler.

Event: 'start_subdoc'
Description: Execute handler at the beginning of every subdocument entity without a specific handler.

Event: 'end_subdoc'
Description: Execute handler at the end of every subdocument entity without a specific handler.

Event: 'conforming'
Description: Execute handler once, at the end of the document parse, if and only if the document was conforming.

The handlers for all of these except the document events 'start' and 'end' will receive two arguments whenever they are called: the first will be the data associated with the event (if any), and the second will be the SGMLS_Event object itself (see the document for SGMLS.pm). Note the following example, which allows processing instructions for including the date or the hostname in the document at parse time:

sgml('pi', sub {
    my ($instruction) = @_;
    if ($instruction eq 'date') {
      output `date`;
    } elsif ($instruction eq 'hostname') {
      output `hostname`;
    } else {
      print STDERR "Warning: unknown processing instruction: $instruction\n";
    }
});

With this handler, any occurance of <?date> in the original SGML document would be replaced by the current date and time, and any occurance of <?hostname> would be replaced by the name of the host.

Links: Next Previous Up Top

David Megginson <dmeggins@aix1.uottawa.ca>

What are the generic events?

Table 1: sgmlspl generic events

Table 1: `sgmlspl` generic events