Text.XML.HXT.XPath.XPathDataTypes

The core data types of XPath. The Type NodeSet is based on the module NavTree which was adapted from HXML (http://www.flightlab.com/~joe/hxml/)

Documentation

data Expr

Represents expression

Constructors

GenExpr Op [Expr]

generic expression with an operator and one or more operands

PathExpr (Maybe Expr) (Maybe LocationPath)

a path expression contains an optional filter-expression or an optional locationpath. one expression is urgently necessary, both are possible

FilterExpr [Expr]

filter-expression with zero or more predicates

VarExpr VarName

variable

LiteralExpr Literal

string

NumberExpr XPNumber

number

FctExpr FctName FctArguments

a function with a name and an optional list of arguments

Instances

Eq Expr

Show Expr

data Op

Represents XPath operators

Constructors

Or

And

Eq

NEq

Less

Greater

LessEq

GreaterEq

Plus

Minus

Div

Mod

Mult

Unary

Union

Instances

Eq Op

Show Op

data XPNumber

Represents a floating-point number according the IEEE 754 standard

The standard includes a special Not-a-Number (NaN) value, positive and negative infinity, positive and negative zero.

Constructors

Float Float

floating-point number

NaN

not-a-number

NegInf

negative infinity

Neg0

negative zero

Pos0

positive zero

PosInf

positive infinity

Instances

Eq XPNumber

Ord XPNumber

Show XPNumber

data LocationPath

Represents location path

A location path consists of a sequence of one or more location steps.

Constructors

LocPath Path [XStep]

Instances

Eq LocationPath

Show LocationPath

data Path

A location path is either a relative or an absolute path.

Constructors

Rel

Abs

Instances

Eq Path

Show Path

data XStep

Represents location step

A location step consists of an axis, a node-test and zero or more predicates.

Constructors

Step AxisSpec NodeTest [Expr]

Instances

Eq XStep

Show XStep

data AxisSpec

Represents XPath axis

Constructors

Ancestor

AncestorOrSelf

Attribute

Child

Descendant

DescendantOrSelf

Following

FollowingSibling

Namespace

Parent

Preceding

PrecedingSibling

Self

Instances

Eq AxisSpec

Show AxisSpec

data NodeTest

Represents XPath node-tests

Constructors

NameTest QName

name-test

PI String

processing-instruction-test with a literal argument

TypeTest XPathNode

all nodetype-tests

Instances

Eq NodeTest

Show NodeTest

data XPathNode

Represents nodetype-tests

Constructors

XPNode

all 7 nodetypes (root, element, attribute, namespace, pi, comment, text)

XPCommentNode

comment-nodes

XPPINode

processing-instruction-nodes

XPTextNode

text-nodes: cdata, character data

Instances

Eq XPathNode

Show XPathNode

type Name = (NamePrefix, LocalName)

type NamePrefix = String

type LocalName = String

type VarName = Name

Variable name

type Literal = String

a string

type FctName = String

Function name

type FctArguments = [Expr]

Function arguments

type Context = (ConPos, ConLen, ConNode)

Evaluation context

type ConPos = Int

Context position

type ConLen = Int

Context length

type ConNode = NavXmlTree

Context node

data XPathValue

Represents XPath results

Constructors

XPVNode NodeSet

node-set

XPVBool Bool

boolean value

XPVNumber XPNumber

number according the IEEE 754 standard

XPVString String

string value

XPVError String

error message with text

Instances

Eq XPathValue

Ord XPathValue

Show XPathValue

type NavXmlTree = NavTree XNode

Node of navigable tree representation

type NavXmlTrees = [NavXmlTree]

List of nodes of navigable tree representation

newtype NodeSet

Set of navigable trees identified by their document position (NodePath)

Constructors

NS

Fields

unNS :: Map NodePath NavXmlTree

Instances

Eq NodeSet

Ord NodeSet

Show NodeSet

type NodePath = [Int]

path represented as list of indices starting at root

type XPathFilter = XPathValue -> XPathValue

A functions that takes a XPath result and returns a XPath result

withXPVNode :: String -> (NodeSet -> XPathValue) -> XPathFilter

emptyNodeSet :: NodeSet

node set functions

singletonNodeSet :: NavXmlTree -> NodeSet

nullNodeSet :: NodeSet -> Bool

cardNodeSet :: NodeSet -> Int

deleteNodeSet :: NodePath -> NodeSet -> NodeSet

insertNodeSet :: NavXmlTree -> NodeSet -> NodeSet

unionNodeSet :: NodeSet -> NodeSet -> NodeSet

unionsNodeSet :: [NodeSet] -> NodeSet

elemsNodeSet :: NodeSet -> [(NodePath, NavXmlTree)]

fromNodeSet :: NodeSet -> NavXmlTrees

toNodeSet :: NavXmlTrees -> NodeSet

headNodeSet :: NodeSet -> NavXmlTree

withNodeSet :: (NavXmlTrees -> NavXmlTrees) -> NodeSet -> NodeSet

type VarTab = [(VarName, XPathValue)]

XPath environment

All variables are stored in the environment, each variable name is bound to a value.

type KeyTab = [(QName, String, NavXmlTree)]

type Env = (VarTab, KeyTab)

varEnv :: Env

module Text.XML.HXT.XPath.NavTree