The XML_TREE signature

The XML_TREE signature defines a tree representation of XML files.

Synopsis

signature XML_TREE

Interface

structure Schema : XML_SCHEMA

datatype doctype = DOCTYPE of string * external_id option

and external_id
  = SYSTEM of string
  | PUBLIC of string * string

datatype content
  = TEXT of string
  | CDATA of string
  | ELEMENT of {
	name : Schema.element,
	attrs : Schema.attribute list,
	content : content list
      }

type tree = {
    xmlDecl : Schema.attribute list option,
    doctype : doctype option,
    content : content
  }

Description

structure Schema : XML_SCHEMA

This substructure defines the representation of elements and attributes.

datatype doctype = DOCTYPE of string * external_id option

This datatype represents the contents of the optional DOCTYPE element found the beginning of the file (following the optional XML declaration). We currently only support external DTDs.

datatype external_id

This datatype represents an external DTD specification; its constructors are defined as follows:

SYSTEM of url

specifies a "private" external DTD, where the string url specifies the DTD’s location.

PUBLIC(name, url)

specifies a "public" external DTD, where the string name is the name of the DTD and url specifies the DTD’s location.

datatype content

This datatype is used to represent the content of an XML file as a tree. The constructors have the following meanings:

TEXT s

represents the text described by the string s. When parsing, entities in the source (e.g., <) are replaced by their definition and, when printing, special characters (e.g., <) are replaced by their entities.

CDATA s

represents the literal text described by the string s.

ELEMENT{name, attrs, content}

represents a subtree enclosed by "`<element>` …​ </element>" tags, where `name is the name of the element, attrs is a list of attributes in the start tag, and content is the stuff between the tags.

type tree

An XML tree, which is a record type with the following fields:

xmlDecl : Schema.attribute list option

This field represents the optional XML declaration at the beginning of a file, where a value of SOME attrs means that there was an XML declaration present with the list of attributes attrs.

doctype : doctype option

This field represents the optional DOCTYPE element that follows the XML declaration.

content : content

This field is the root of the content and will always be an ELEMENT.

See Also

XML_SCHEMA, XMLTreeFn, The XML Library