View Source xmerl_xpath (xmerl v2.1)

Xpath 1.0 search implementation.

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')")).

Summary

Types

nodeEntity()

option_list()

Options to customize the behaviour of the XPath scanner.

parentList()

xPathString()

Functions

string(String, Doc)

Equivalent to string(String, Doc, [], Doc, []).

string(String, Doc, Options)

Equivalent to string(String, Doc, [], Doc, Options).

string(String, Node, Parents, Doc, Options)

Extract nodes from a parsed XML tree.

Types

nodeEntity()

(not exported)

-type nodeEntity() ::
          xmerl:xmlElement() |
          xmerl:xmlAttribute() |
          xmerl:xmlText() |
          xmerl:xmlPI() |
          xmerl:xmlComment() |
          xmerl:xmlNsNode() |
          xmerl:xmlDocument().

option_list()

(not exported)

-type option_list() :: [{atom(), term()}].

Options to customize the behaviour of the XPath scanner.

Possible options are:

{namespace, #xmlNamespace}: Set namespace nodes, from XmlNamspace, in xmlContext
{namespace, Nodes}: Set namespace nodes in xmlContext.

parentList()

(not exported)

-type parentList() :: [{atom(), integer()}].

xPathString()

(not exported)

-type xPathString() :: string().

Functions

string(String, Doc)

-spec string(String, Doc) -> _ when String :: xPathString(), Doc :: nodeEntity().

Equivalent to string(String, Doc, [], Doc, []).

string(String, Doc, Options)

-spec string(String, Doc, Options) -> _
                when String :: xPathString(), Doc :: nodeEntity(), Options :: option_list().

Equivalent to string(String, Doc, [], Doc, Options).

string(String, Node, Parents, Doc, Options)

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

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.