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IADIS International Conference WWW/Internet 2010. . .Figure 1. Example of an extended link.childparentlink:definitionLinklink:locsiblinglink:loclink:definitionArclink:loclink:definitionArcFigure 2. Extended link nodes tree.As an example of XPath expression, the following location path may be used to find, from the XMLdocument root, the element locator whose label is “BankingActivitiesDomain”:/descendant‐or‐self::link:definitionLink/child::link:loc[@xlink:label=”BankingActivitiesDomain”]. The query resulting fromthe computation of this expression is performed in stages called location steps (isolated by “/”), whosegeneral form is: axis::nodeSpecification[Predicate].The axis indicates in each direction from one reference node – called context node – the query must beperformed, placed that in majority of cases this direction regards to one of the relationships of the XML tree.The node specification determines which nodes in this direction must be selected. Besides that, it is possibleto filter the result using a predicate (optional), which consists in a boolean test applied to the selected node:when the result is true, the node is maintained; otherwise, it is discarded. The expression organization insuccessive location steps allows any node in the tree to be accessed, making XPath an ideal tool fornavigating in this type of structure. XPath has been seen as a de facto standard in the XML query researcharea. However, it does not provide a means of navigating through XLink links. As a result, both thesemantics and the processing issues concerning link data are compromised.When the interest is exploring the information according to the extended links perspective, this solutionappears to be insufficient. For example, to formulate a query whose purpose is to select all the destinyelements of arcs, whose source is the element d-ba_TotalBankingActivities, two important issues must beconsidered: (i) differently from a traditional XML tree, the data structure resulting from referencesestablished by the links characterize a network; and (ii) there is no restriction regarding the location of areferred resource, which may be in any part of the XML document or, yet, in a distinct document. Thus,exploring the information related by the extended link using XPath, when it is not possible (in the case ofrefreences between distinct XML documents), demands a formulation of complex queries. With XQuery thesituation is not different, since mechanisms as FLWOR clauses are not proper for navigation in links. It isevident, therefore, the need for a query language specialized in the extended links mechanism. However, it isimportant to ponder that the development of a language based on a completely new syntax would cause abigger difficult assimilation from the users who are already familiar with XPath syntax. To minimize thisimpact, it is desirable the existence of a proximity between these syntaxes. The language proposed in thispaper, XLPath, is based on location path expressions of XPath, in which new axis, node tests and predicateswere developed aiming the navigation through the networks formed by extended links.91