xmerl_xpath(3)

NAME
xmerl_xpath - Xpath 1.0 search implementation.

DESCRIPTION

The xmerl_xpath module handles the entire XPath 1.0 spec. XPath expressions typically occur in XML attributes and are used to address parts of an XML document. The grammar is defined in xmerl_xpath_parse.yrl. The core functions are defined in xmerl_xpath_pred.erl.

Some useful shell commands for debugging the XPath parser

     c(xmerl_xpath_scan).
     yecc:yecc("xmerl_xpath_parse.yrl", "xmerl_xpath_parse", true, []).
     c(xmerl_xpath_parse).
     xmerl_xpath_parse:parse(xmerl_xpath_scan:tokens("position() > -1")).
     xmerl_xpath_parse:parse(xmerl_xpath_scan:tokens("5 * 6 div 2")).
     xmerl_xpath_parse:parse(xmerl_xpath_scan:tokens("5 + 6 mod 2")).
     xmerl_xpath_parse:parse(xmerl_xpath_scan:tokens("5 * 6")).
     xmerl_xpath_parse:parse(xmerl_xpath_scan:tokens("-----6")).
     xmerl_xpath_parse:parse(xmerl_xpath_scan:tokens("parent::node()")).
     xmerl_xpath_parse:parse(xmerl_xpath_scan:tokens("descendant-or-self::node()")).
     xmerl_xpath_parse:parse(xmerl_xpath_scan:tokens("parent::processing-instruction('foo')")).

DATA TYPES

nodeEntity() :: xmerl:xmlElement() | xmerl:xmlAttribute() | xmerl:xmlText() | xmerl:xmlPI() | xmerl:xmlComment() | xmerl:xmlNsNode() | xmerl:xmlDocument().
option_list() :: [{atom(), term()}].

    Options to customize the behaviour of the XPath scanner.

    Possible options are:

    <dl> <dt><code>{namespace, #xmlNamespace}</code></dt> <dd>Set namespace nodes, from XmlNamspace, in xmlContext</dd> <dt><code>{namespace, Nodes}</code></dt> <dd>Set namespace nodes in xmlContext.</dd> </dl>
parentList() :: [{atom(), integer()}].
xPathString() :: string().

FUNCTIONS

string(String, Node, Parents, Doc, Options) -> [nodeEntity()] | Scalar when String :: xPathString(), Node :: nodeEntity(), Parents :: parentList(), Doc :: nodeEntity(), Options :: option_list(), Scalar :: #xmlObj{}.

    Extract nodes from a parsed XML tree.

    Extracts the nodes from the parsed XML tree according the XPath String.

    Scalar is an #xmlObj{} record record with the fields type and value, where #xmlObj.type is boolean | number | string.