tm (version 0.6-1)

XMLSource: XML Source

Description

Create an XML source.

Usage

XMLSource(x, parser, reader)

Arguments

x

a character giving a uniform resource identifier.

parser

a function accepting an XML tree (as delivered by xmlTreeParse in package XML) as input and returning a list of XML elements.

reader

a function capable of turning XML elements as returned by parser into a subclass of TextDocument.

Value

• An object inheriting from XMLSource, SimpleSource, and Source.

See Also

Source for basic information on the source infrastructure employed by package tm.

Vignette 'Extensions: How to Handle Custom File Formats', and readXML.

Examples

## An implementation for readGmane is provided as an example in ?readXML
example(readXML)

## Construct a source for a Gmane mailing list RSS feed.
GmaneSource <-
function(x)
    XMLSource(x,
              function(tree) {
                  nodes <- XML::xmlChildren(XML::xmlRoot(tree))
                  nodes[names(nodes) == "item"]
              },
              readGmane)
gs <- GmaneSource("http://rss.gmane.org/gmane.comp.lang.r.general")
elem <- getElem(stepNext(gs))
(gmane <- readGmane(elem, language = "en", id = "id1"))
meta(gmane)