View Source xmerl_xpath (xmerl v1.4)

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

docEntity()

docNodes()

nodeEntity()

option_list()

parentList()

xPathString()

Functions

string(Str,Doc)

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

string(Str,Doc,Options)

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

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

Extracts the nodes from the parsed XML tree according to XPath. xmlObj is a record with fields type and value, where type is boolean | number | string

Types

docEntity()

(not exported)

-type docEntity() :: #xmlDocument{content :: term()} | [docNodes()].

docNodes()

(not exported)

-type docNodes() ::
    #xmlElement{name :: term(),
                expanded_name :: term(),
                nsinfo :: term(),
                namespace :: term(),
                parents :: term(),
                pos :: term(),
                attributes :: term(),
                content :: term(),
                language :: term(),
                xmlbase :: term(),
                elementdef :: term()} |
    #xmlAttribute{name :: term(),
                  expanded_name :: term(),
                  nsinfo :: term(),
                  namespace :: term(),
                  parents :: term(),
                  pos :: term(),
                  language :: term(),
                  value :: term(),
                  normalized :: term()} |
    #xmlText{parents :: term(),
             pos :: term(),
             language :: term(),
             value :: term(),
             type :: term()} |
    #xmlPI{name :: term(), parents :: term(), pos :: term(), value :: term()} |
    #xmlComment{parents :: term(), pos :: term(), language :: term(), value :: term()} |
    #xmlNsNode{parents :: term(), pos :: term(), prefix :: term(), uri :: term()}.

nodeEntity()

(not exported)

-type nodeEntity() ::
    #xmlElement{name :: term(),
                expanded_name :: term(),
                nsinfo :: term(),
                namespace :: term(),
                parents :: term(),
                pos :: term(),
                attributes :: term(),
                content :: term(),
                language :: term(),
                xmlbase :: term(),
                elementdef :: term()} |
    #xmlAttribute{name :: term(),
                  expanded_name :: term(),
                  nsinfo :: term(),
                  namespace :: term(),
                  parents :: term(),
                  pos :: term(),
                  language :: term(),
                  value :: term(),
                  normalized :: term()} |
    #xmlText{parents :: term(),
             pos :: term(),
             language :: term(),
             value :: term(),
             type :: term()} |
    #xmlPI{name :: term(), parents :: term(), pos :: term(), value :: term()} |
    #xmlComment{parents :: term(), pos :: term(), language :: term(), value :: term()} |
    #xmlNsNode{parents :: term(), pos :: term(), prefix :: term(), uri :: term()} |
    #xmlDocument{content :: term()}.

option_list()

(not exported)

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

parentList()

(not exported)

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

xPathString()

(not exported)

-type xPathString() :: string().

Functions

string(Str,Doc)

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

string(Str,Doc,Options)

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

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

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

Extracts the nodes from the parsed XML tree according to XPath. xmlObj is a record with fields type and value, where type is boolean | number | string