SAXState-class {XML} | R Documentation

## A virtual base class defining methods for SAX parsing

### Description

This is a degenerate virtual class which others are expected to sub-class so as to define when they want to use S4 methods as handler functions for SAX-based XML parsing. The idea is that one can pass both i) a collection of handlers to `xmlEventParse` which are simply the generic functions for the different SAX actions, and ii) a suitable object to maintain state across the different SAX calls. This is used to perform the method dispatching to get the appropriate behavior for the action. Each of these methods is expected to return the updated state object and the SAX parser will pass this in the next callback.

We define this class here so that we can provide default methods for each of the different handler actions. This allows other programmers to define new classes to maintain state that are sub-class of `SAXState` and then they do not have to implement methods for each of the different handlers.

### Objects from the Class

A virtual Class: No objects may be created from it.

### Methods

comment.SAX
  `signature(content = "ANY", .state = "SAXState")`: ...
endElement.SAX
  `signature(name = "ANY", .state = "SAXState")`: ...
entityDeclaration.SAX
  `signature(name = "ANY", base = "ANY", sysId = "ANY", publicId = "ANY", notationName = "ANY", .state = "SAXState")`: ...
processingInstruction.SAX
  `signature(target = "ANY", content = "ANY", .state = "SAXState")`: ...
startElement.SAX
  `signature(name = "ANY", atts = "ANY", .state = "SAXState")`: ...
text.SAX
  `signature(content = "ANY", .state = "SAXState")`: ...

### Author(s)

Duncan Temple Lang

### References

http://www.w3.org/XML, http://www.xmlsoft.org

### See Also

`xmlEventParse`

### Examples

[Package XML version 0.97-7 Index]