Safe Haskell	None
Language	Haskell98

Text.XmlHtml

Contents

Types
Manipulating documents
Parsing
Rendering

Description

Parsers and renderers for XML and HTML 5. Although the formats are treated differently, the data types used by each are the same, which makes it easy to write code that works with the element structure of either XML or HTML 5 documents.

Limitations:

The XML parser does not parse internal DOCTYPE subsets. They are just stored as blocks of text, with minimal scanning done to match quotes and brackets to determine the end.
Since DTDs are not parsed, the XML parser fails on entity references, except for those defined internally. You cannot use this library for parsing XML documents with entity references outside the predefined set.
The HTML 5 parser is not a compliant HTML parser. Instead, it is a parser for valid HTML 5 content. It should only be used on content that you have reason to believe is probably correct, since the compatibility features of HTML 5 are missing. This is the wrong library on which to build a web spider.
Both parsers accept fragments of documents, by which is meant that they do not enforce the top-level structure of the document. Files may contain more than one root element, for example.

Synopsis

Types

data Document Source

Represents a document fragment, including the format, encoding, and document type declaration as well as its content.

Constructors

XmlDocument
Fields docEncoding :: !Encoding docType :: !(Maybe DocType) docContent :: ![Node]
HtmlDocument
Fields docEncoding :: !Encoding docType :: !(Maybe DocType) docContent :: ![Node]

Instances

Eq Document
Show Document

data Node Source

A node of a document structure. A node can be text, a comment, or an element. XML processing instructions are intentionally omitted as a simplification, and CDATA and plain text are both text nodes, since they ought to be semantically interchangeable.

Constructors

TextNode !Text
Comment !Text
Element
Fields elementTag :: !Text elementAttrs :: ![(Text, Text)] elementChildren :: ![Node]

Instances

Eq Node
Show Node

data DocType Source

A document type declaration. Note that DTD internal subsets are currently unimplemented.

Constructors

DocType !Text !ExternalID !InternalSubset

Instances

Eq DocType
Show DocType

data ExternalID Source

An external ID, as in a document type declaration. This can be a SYSTEM identifier, or a PUBLIC identifier, or can be omitted.

Constructors

Public !Text !Text
System !Text
NoExternalID

Instances

Eq ExternalID
Show ExternalID

data InternalSubset Source

The internal subset is unparsed, but preserved in case it's actually wanted.

Constructors

InternalText !Text
NoInternalSubset

Instances

Eq InternalSubset
Show InternalSubset

data Encoding Source

The character encoding of a document. Currently only the required character encodings are implemented.

Constructors

UTF8
UTF16BE
UTF16LE

Instances

Eq Encoding
Show Encoding

Manipulating documents

isTextNode :: Node -> Bool Source

Determines whether the node is text or not.

isComment :: Node -> Bool Source

Determines whether the node is a comment or not.

isElement :: Node -> Bool Source

Determines whether the node is an element or not.

tagName :: Node -> Maybe Text Source

Gives the tag name of an element, or Nothing if the node isn't an element.

getAttribute :: Text -> Node -> Maybe Text Source

Retrieves the attribute with the given name. If the Node is not an element, the result is always Nothing

hasAttribute :: Text -> Node -> Bool Source

Checks if a given attribute exists in a Node.

setAttribute :: Text -> Text -> Node -> Node Source

Sets the attribute name to the given value. If the Node is not an element, this is the identity.

nodeText :: Node -> Text Source

Gives the entire text content of a node, ignoring markup.

childNodes :: Node -> [Node] Source

Gives the child nodes of the given node. Only elements have child nodes.

childElements :: Node -> [Node] Source

Gives the child elements of the given node.

childElementsTag :: Text -> Node -> [Node] Source

Gives all of the child elements of the node with the given tag name.

childElementTag :: Text -> Node -> Maybe Node Source

Gives the first child element of the node with the given tag name, or Nothing if there is no such child element.

descendantNodes :: Node -> [Node] Source

Gives the descendants of the given node in the order that they begin in the document.

descendantElements :: Node -> [Node] Source

Gives the descendant elements of the given node, in the order that their start tags appear in the document.

descendantElementsTag :: Text -> Node -> [Node] Source

Gives the descendant elements with a given tag name.

descendantElementTag :: Text -> Node -> Maybe Node Source

Gives the first descendant element of the node with the given tag name, or Nothing if there is no such element.

Parsing

parseXML Source

Arguments

:: String	Name of document source (perhaps a filename) for error messages
-> ByteString	Document contents
-> Either String Document	The document or an error message

Parses the given XML fragment.

parseHTML Source

Arguments

:: String	Name of document source (perhaps a filename) for error messages
-> ByteString	Document contents
-> Either String Document	The document or an error message

Parses the given HTML fragment. This enables HTML quirks mode, which changes the parsing algorithm to parse valid HTML 5 documents correctly.

Rendering

render :: Document -> Builder Source

Renders a Document.

renderXmlFragment :: Encoding -> [Node] -> Builder Source

Function for rendering XML nodes without the overhead of creating a Document structure.

renderHtmlFragment :: Encoding -> [Node] -> Builder Source

Function for rendering HTML nodes without the overhead of creating a Document structure.

renderDocType :: Encoding -> Maybe DocType -> Builder Source