Text.XML.HXT.Arrow.XmlArrow

Basic arrows for processing XML documents

All arrows use IO and a global state for options, errorhandling, ...

Documentation

class (Arrow a, ArrowList a, ArrowTree a) => ArrowXml a where

Arrows for processing XmlTrees

These arrows can be grouped into predicates, selectors, constructors, and transformers.

All predicates (tests) act like none for failure and this for success. A logical and can be formed by a1 >>> a2 , a locical or by a1 <+> a2 .

Selector arrows will fail, when applied to wrong input, e.g. selecting the text of a node with getText will fail when applied to a none text node.

Edit arrows will remain the input unchanged, when applied to wrong argument, e.g. editing the content of a text node with changeText applied to an element node will return the unchanged element node.

Methods

isText :: a XmlTree XmlTree

test for text nodes

isBlob :: a XmlTree XmlTree

isCharRef :: a XmlTree XmlTree

test for char reference, used during parsing

isEntityRef :: a XmlTree XmlTree

test for entity reference, used during parsing

isCmt :: a XmlTree XmlTree

test for comment

isCdata :: a XmlTree XmlTree

test for CDATA section, used during parsing

isPi :: a XmlTree XmlTree

test for processing instruction

isXmlPi :: a XmlTree XmlTree

test for processing instruction <?xml ...>

isElem :: a XmlTree XmlTree

test for element

isDTD :: a XmlTree XmlTree

test for DTD part, used during parsing

isAttr :: a XmlTree XmlTree

test for attribute tree

isError :: a XmlTree XmlTree

test for error message

isRoot :: a XmlTree XmlTree

test for root node (element with name "/")

hasText :: (String -> Bool) -> a XmlTree XmlTree

test for text nodes with text, for which a predicate holds

example: hasText (all (`elem` " \t\n")) check for text nodes with only whitespace content

isWhiteSpace :: a XmlTree XmlTree

test for text nodes with only white space

implemented with hasTest

hasNameWith :: (QName -> Bool) -> a XmlTree XmlTree

test whether a node (element, attribute, pi) has a name with a special property

hasQName :: QName -> a XmlTree XmlTree

test whether a node (element, attribute, pi) has a specific qualified name useful only after namespace propagation

hasName :: String -> a XmlTree XmlTree

test whether a node has a specific name (prefix:localPart ore localPart), generally useful, even without namespace handling

hasLocalPart :: String -> a XmlTree XmlTree

test whether a node has a specific name as local part, useful only after namespace propagation

hasNamePrefix :: String -> a XmlTree XmlTree

test whether a node has a specific name prefix, useful only after namespace propagation

hasNamespaceUri :: String -> a XmlTree XmlTree

test whether a node has a specific namespace URI useful only after namespace propagation

hasAttr :: String -> a XmlTree XmlTree

test whether an element node has an attribute node with a specific name

hasQAttr :: QName -> a XmlTree XmlTree

test whether an element node has an attribute node with a specific qualified name

hasAttrValue :: String -> (String -> Bool) -> a XmlTree XmlTree

test whether an element node has an attribute with a specific value

hasQAttrValue :: QName -> (String -> Bool) -> a XmlTree XmlTree

test whether an element node has an attribute with a qualified name and a specific value

mkText :: a String XmlTree

text node construction arrow

mkBlob :: a Blob XmlTree

blob node construction arrow

mkCharRef :: a Int XmlTree

char reference construction arrow, useful for document output

mkEntityRef :: a String XmlTree

entity reference construction arrow, useful for document output

mkCmt :: a String XmlTree

comment node construction, useful for document output

mkCdata :: a String XmlTree

CDATA construction, useful for document output

mkError :: Int -> a String XmlTree

error node construction, useful only internally

mkElement :: QName -> a n XmlTree -> a n XmlTree -> a n XmlTree

element construction: | the attributes and the content of the element are computed by applying arrows to the input

mkAttr :: QName -> a n XmlTree -> a n XmlTree

attribute node construction: | the attribute value is computed by applying an arrow to the input

mkPi :: QName -> a n XmlTree -> a n XmlTree

processing instruction construction: | the content of the processing instruction is computed by applying an arrow to the input

mkqelem :: QName -> [a n XmlTree] -> [a n XmlTree] -> a n XmlTree

convenient arrow for element construction, more comfortable variant of mkElement

example for simplifying mkElement :

 mkElement qn (a1 <+> ... <+> ai) (c1 <+> ... <+> cj)

equals

 mkqelem qn [a1,...,ai] [c1,...,cj]

mkelem :: String -> [a n XmlTree] -> [a n XmlTree] -> a n XmlTree

convenient arrow for element construction with strings instead of qualified names as element names, see also mkElement and mkelem

aelem :: String -> [a n XmlTree] -> a n XmlTree

convenient arrow for element constrution with attributes but without content, simple variant of mkelem and mkElement

selem :: String -> [a n XmlTree] -> a n XmlTree

convenient arrow for simple element constrution without attributes, simple variant of mkelem and mkElement

eelem :: String -> a n XmlTree

convenient arrow for constrution of empty elements without attributes, simple variant of mkelem and mkElement

root :: [a n XmlTree] -> [a n XmlTree] -> a n XmlTree

construction of an element node with name "/" for document roots

qattr :: QName -> a n XmlTree -> a n XmlTree

alias for mkAttr

attr :: String -> a n XmlTree -> a n XmlTree

convenient arrow for attribute constrution, simple variant of mkAttr

txt :: String -> a n XmlTree

constant arrow for text nodes

blb :: Blob -> a n XmlTree

constant arrow for blob nodes

charRef :: Int -> a n XmlTree

constant arrow for char reference nodes

entityRef :: String -> a n XmlTree

constant arrow for entity reference nodes

cmt :: String -> a n XmlTree

constant arrow for comment

warn :: String -> a n XmlTree

constant arrow for warning

err :: String -> a n XmlTree

constant arrow for errors

fatal :: String -> a n XmlTree

constant arrow for fatal errors

spi :: String -> String -> a n XmlTree

constant arrow for simple processing instructions, see mkPi

sqattr :: QName -> String -> a n XmlTree

constant arrow for attribute nodes, attribute name is a qualified name and value is a text, | see also mkAttr, qattr, attr

sattr :: String -> String -> a n XmlTree

constant arrow for attribute nodes, attribute name and value are | given by parameters, see mkAttr

getText :: a XmlTree String

select the text of a text node

getCharRef :: a XmlTree Int

select the value of a char reference

getEntityRef :: a XmlTree String

select the name of a entity reference node

getCmt :: a XmlTree String

select the comment of a comment node

getCdata :: a XmlTree String

select the content of a CDATA node

getPiName :: a XmlTree QName

select the name of a processing instruction

getPiContent :: a XmlTree XmlTree

select the content of a processing instruction

getElemName :: a XmlTree QName

select the name of an element node

getAttrl :: a XmlTree XmlTree

select the attribute list of an element node

getDTDPart :: a XmlTree DTDElem

select the DTD type of a DTD node

getDTDAttrl :: a XmlTree Attributes

select the DTD attributes of a DTD node

getAttrName :: a XmlTree QName

select the name of an attribute

getErrorLevel :: a XmlTree Int

select the error level (c_warn, c_err, c_fatal) from an error node

getErrorMsg :: a XmlTree String

select the error message from an error node

getQName :: a XmlTree QName

select the qualified name from an element, attribute or pi

getName :: a XmlTree String

select the prefix:localPart or localPart from an element, attribute or pi

getUniversalName :: a XmlTree String

select the univeral name ({namespace URI} ++ localPart)

getUniversalUri :: a XmlTree String

select the univeral name (namespace URI ++ localPart)

getLocalPart :: a XmlTree String

select the local part

getNamePrefix :: a XmlTree String

select the name prefix

getNamespaceUri :: a XmlTree String

select the namespace URI

getAttrValue :: String -> a XmlTree String

select the value of an attribute of an element node, always succeeds with empty string as default value ""

getAttrValue0 :: String -> a XmlTree String

like getAttrValue, but fails if the attribute does not exist

getQAttrValue :: QName -> a XmlTree String

like getAttrValue, but select the value of an attribute given by a qualified name, always succeeds with empty string as default value ""

getQAttrValue0 :: QName -> a XmlTree String

like getQAttrValue, but fails if attribute does not exist

changeText :: (String -> String) -> a XmlTree XmlTree

edit the string of a text node

changeBlob :: (Blob -> Blob) -> a XmlTree XmlTree

edit the blob of a blob node

changeCmt :: (String -> String) -> a XmlTree XmlTree

edit the comment string of a comment node

changeQName :: (QName -> QName) -> a XmlTree XmlTree

edit an element-, attribute- or pi- name

changeElemName :: (QName -> QName) -> a XmlTree XmlTree

edit an element name

changeAttrName :: (QName -> QName) -> a XmlTree XmlTree

edit an attribute name

changePiName :: (QName -> QName) -> a XmlTree XmlTree

edit a pi name

changeAttrValue :: (String -> String) -> a XmlTree XmlTree

edit an attribute value

changeAttrl :: (XmlTrees -> XmlTrees -> XmlTrees) -> a XmlTree XmlTree -> a XmlTree XmlTree

edit an attribute list of an element node

setQName :: QName -> a XmlTree XmlTree

replace an element, attribute or pi name

setElemName :: QName -> a XmlTree XmlTree

replace an element name

setAttrName :: QName -> a XmlTree XmlTree

replace an attribute name

setPiName :: QName -> a XmlTree XmlTree

replace an element name

setAttrl :: a XmlTree XmlTree -> a XmlTree XmlTree

replace an atribute list of an element node

addAttrl :: a XmlTree XmlTree -> a XmlTree XmlTree

add a list of attributes to an element

addAttr :: String -> String -> a XmlTree XmlTree

add (or replace) an attribute

removeAttr :: String -> a XmlTree XmlTree

remove an attribute

removeQAttr :: QName -> a XmlTree XmlTree

remove an attribute with a qualified name

processAttrl :: a XmlTree XmlTree -> a XmlTree XmlTree

process the attributes of an element node with an arrow

processTopDownWithAttrl :: a XmlTree XmlTree -> a XmlTree XmlTree

process a whole tree inclusive attribute list of element nodes see also: processTopDown

(+=) :: a b XmlTree -> a b XmlTree -> a b XmlTree

convenient op for adding attributes or children to a node

usage: tf += cf

the tf arrow computes an element node, and all trees computed by cf are added to this node, if a tree is an attribute, it is inserted in the attribute list else it is appended to the content list.

attention: do not build long content list this way because += is implemented by ++

examples:

 eelem "a"
   += sattr "href" "page.html"
   += sattr "name" "here"
   += txt "look here"

is the same as

 mkelem [ sattr "href" "page.html"
        , sattr "name" "here"
        ]
        [ txt "look here" ]

and results in the XML fragment: <a href="page.html" name="here">look here</a>

advantage of the += operator is, that attributes and content can be added any time step by step. if tf computes a whole list of trees, e.g. a list of "td" or "tr" elements, the attributes or content is added to all trees. useful for adding "class" or "style" attributes to table elements.

xshow :: a n XmlTree -> a n String

apply an arrow to the input and convert the resulting XML trees into a string representation

xshowBlob :: a n XmlTree -> a n Blob

apply an arrow to the input and convert the resulting XML trees into a string representation

Instances

ArrowXml LA

ArrowXml IOLA

(Arrow (SLA s), ArrowList (SLA s), ArrowTree (SLA s)) => ArrowXml (SLA s)

(Arrow (IOSLA s), ArrowList (IOSLA s), ArrowTree (IOSLA s)) => ArrowXml (IOSLA s)

class ArrowXml a => ArrowDTD a where

Document Type Definition arrows

These are separated, because they are not needed for document processing, only when processing the DTD, e.g. for generating access funtions for the toolbox from a DTD (se example DTDtoHaskell in the examples directory)

Methods

isDTDDoctype :: a XmlTree XmlTree

isDTDElement :: a XmlTree XmlTree

isDTDContent :: a XmlTree XmlTree

isDTDAttlist :: a XmlTree XmlTree

isDTDEntity :: a XmlTree XmlTree

isDTDPEntity :: a XmlTree XmlTree

isDTDNotation :: a XmlTree XmlTree

isDTDCondSect :: a XmlTree XmlTree

isDTDName :: a XmlTree XmlTree

isDTDPERef :: a XmlTree XmlTree

hasDTDAttr :: String -> a XmlTree XmlTree

getDTDAttrValue :: String -> a XmlTree String

setDTDAttrValue :: String -> String -> a XmlTree XmlTree

mkDTDElem :: DTDElem -> Attributes -> a n XmlTree -> a n XmlTree

mkDTDDoctype :: Attributes -> a n XmlTree -> a n XmlTree

mkDTDElement :: Attributes -> a n XmlTree

mkDTDEntity :: Attributes -> a n XmlTree

mkDTDPEntity :: Attributes -> a n XmlTree

Instances

ArrowDTD LA

ArrowDTD IOLA

ArrowXml (SLA s) => ArrowDTD (SLA s)

ArrowXml (IOSLA s) => ArrowDTD (IOSLA s)