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

dtdElement {XML} | R Documentation

## 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. \ One can read a DTD directly (using `parseDTD`) or implicitly when reading a document (using `xmlTreeParse`) 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.net

### See Also

`parseDTD`, `dtdValidElement`

### 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)

[Package XML version 3.99-0.3 Index]