Gets the definition of an element or entity from a DTD.

DESCRIPTION:

A DTD in R consists of both element and entity definitions. These two functions provide simple access to individual elements of these two lists, using the name of the element or entity. The DTD is provided to determine where to look for the entry.

USAGE:

 
dtdElement(name,dtd)
dtdEntity(name,dtd)

ARGUMENTS:

name
The name of the element being retrieved/acessed.
dtd
The DTD from which the element is to be retrieved.

DETAILS:

An element within a DTD contains both the list of sub-elements it can contain and a list of attributes that can be used within this tag type. dtdElement retrieves the element by name from the specified DTD definition. Entities within a DTD are like macros or text substitutes used within a DTD and/or XML documents that use it. Each consists of a name/label and a definition, the text that is substituted when the entity is referenced. dtdEntity retrieves the entity definition from the DTD. Note that the entities that are defined only for use within DTD parsing are not returned as part of the DTD definition. One can read a DTD directly (using ) or implicitly when reading a document (using ) The names of all available elements can be obtained from the expression names(dtd$elements) . This function is simply a convenience for indexing this elements list.

VALUE:

An object of class XMLElementDef.

AUTHOR(S):

Duncan Temple Lang

REFERENCES:

http://www.w3.org/XML, http://www.jclark.com/xml, http://www.omegahat.org

SEE ALSO:

,

EXAMPLES:

 dtdFile <- system.file("exampleData", "foo.dtd", package="XML")
 foo.dtd <- parseDTD(dtdFile)

   # Get the definition of the `entry1' element
 tmp <- dtdElement("variable", foo.dtd)
 xmlAttrs(tmp)

 tmp <- dtdElement("entry1", foo.dtd)

  # Get the definition of the `img' entity
 dtdEntity("img", foo.dtd)