Text.XML.HXT.XPath.XPathFct

The module contains the core-functions of the XPath function library. All functions are implemented as XFct. Each XFct contains the evaluation context, the variable environment and the function arguments.

Documentation

type XFct = Context -> Env -> [XPathValue] -> XPathValue

Type signature for all functions which can be used in the XPath module.

evalFct :: FctName -> Env -> Context -> [XPathValue] -> XPathValue

Evaluates a function. Calculation of the function value is done by looking up the function name in the function table, check the number of arguments and calculate the funtion, if no argument evaluation returns an error.

• returns : the function value as XPathValue

toXValue :: XFct -> Context -> Env -> [XPathValue] -> [XPathValue]

Converts a list of different XPathValue types in a list of one XPathValue type.

• 1.parameter fct : the conversion function

xnumber :: XFct

number number(object?): converts its argument to a number

xboolean :: XFct

boolean boolean(object): converts its argument to a boolean value

xstring :: XFct

string string(object?): converts an object to a string

getConvFct :: XPathValue -> Maybe XFct

Returns the conversion function for the XPath results: string, boolean and number A nodeset can not be converted.

stringValue :: NavXmlTree -> XPathValue

Returns the string-value of a node, the value of a namespace node is not supported

isNotInNodeList :: NavXmlTree -> [NavXmlTree] -> Bool

Check whether a node is not a part of a node list. Needed to implement matching & testing in xslt.

getVarTab :: Env -> VarTab

Returns the table of variables from the environment

getKeyTab :: Env -> KeyTab

Returns the table of keys, needed by xslt, from the environment