---
name: "XML::SAX::Expat::Incremental"
section: "3pm"
platform: "linux"
package: "libxml-sax-expat-incremental-perl"
version: "0.05-3"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/XML::SAX::Expat::Incremental"
---

# XML::SAX::Expat::Incremental(3pm)

XML::SAX::Expat subclass for non-blocking (incremental) parsing, with XML::Parser::ExpatNB.

## NAME

XML::SAX::Expat::Incremental - XML::SAX::Expat subclass for non-blocking (incremental) parsing, with XML::Parser::ExpatNB.

## SYNOPSIS

```
        use XML::SAX::Expat::Incremental;
        # don't do this, use XML::SAX::ParserFactory
        my $p = XML::SAX::Expat::Incremental->new( Handler => MyHandler->new );
        $p->parse_start;
        while (<DATA>){
                $p->parse_more($_); # or $p->parse_string($_);
        }
        $p->parse_done;
```

## DESCRIPTION

Most XML parsers give a callback interface within an encapsulated loop. That is, you call

```
        $p->parse_whatever($whatever);
```

And eventually, when `$whatever` is depleted by the parser, `"$p->parse"` will return.

Sometimes you don't want the parser to control the loop for you. For example, if you need to retrieve your XML in chunks in a funny way, you might need to do something like

```
        my $doc = '';
        while (defined(my $buffer = get_more_xml())) {
                $doc .= $buffer;
        }
        $p->parse_string($doc);
```

which is not very convenient, or efficient. You could use perltie to tie a filehandle which does this for you, but that only works some of the time (for example, say you have two inputs coming in simultaneously).

XML::Parser::ExpatNB solves this by providing three methods:

- parse\_start

  - parse\_more

  - parse\_done

  This interface lets you move the loop to outside the parser, retaining control.

The callbacks are executed in the same manner, just that now, when there is no left to parse, instead of taking more data from a source on it's own, the parser returns control to you.

```
        $p->parse_start; # you can omit this - parse_start will
                         # be called automatically as needed
        while(defined(my $buffer = get_more_xml())) {
                $p->parse_more($buffer);
        }
        $p->parse_done;
```

This module is a subclass of XML::SAX::Expat which is to XML::Parser::ExpatXS as XML::SAX::Expat is to XML::Parser itself.

## METHODS

- parse\_string STRING

  - parse\_more STRING

  These have the same effect, except that parse\_more actually calls parse\_string with `@_`. You might want to use parse\_string because in theory it's more efficient.

  This simply continues parsing with the new string, and sends SAX events for the data that is complete in the string.

- parse\_start

  This calls parse\_start on the underlying XML::Parser::ExpatNB object. It's called implicitly when you first call parse\_string, though, so you don't have to worry about it.

- parse\_done

  This calls parse\_done on the underlying XML::Parser::ExpatNB object. You use it to tell the parser you have no more data to give it.

- parse

  This is used internally as a sort of parse-anything method. Don't use it, instead use `"parse_string"`, which invokes this method correctly, and takes simpler options.

## SEE ALSO

XML::Parser, XML::SAX, XML::SAX::Expat, XML::SAX::ExpatNB

## VERSION CONTROL

This module is maintained using Darcs. You can get the latest version from \<http://nothingmuch.woobling.org/XML-SAX-Expat-Incremental/\>, and use `"darcs` `send"` to commit changes.

## AUTHOR

Yuval Kogman \<nothingmuch@woobling.org\>

## COPYRIGHT & LICENSE

```
        Copyright (c) 2005 Yuval Kogman. All rights reserved
        This program is free software; you can redistribute
        it and/or modify it under the same terms as Perl itself.
```