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15 <h1 align="center">MathQL-1</h1>
17 <h2 align="center">A query language for RDF metadata</h2>
19 <table cellpadding="10" cellspacing="2" border="0" width="95%"
23 <td valign="top" align="left">
26 <li><a href="index.html">Forward</a><br>
33 <li><a href="features.html">Features</a></li>
44 <li><a href="documentation.html">Documentation</a></li>
50 <li><a href="implementation.html">Implementation</a><br>
56 <li><a href="authors.html">The authors</a><br>
63 <li><a href="links.html">Links</a><br>
71 <div align="right"><b>What's new</b><br>
74 This page reports the newly <a href="implementation.html">implemented</a>
75 features of MathQL-1 that are not included in the ufficial <a
76 href="documentation.html">documentation</a> yet.<br>
78 Changes and additions to MathQL-1 operators:<br>
80 <li>The <b>add</b> operator now accepts a syntax extension allowing
81 to specify more than one explicit attribute group.</li>
83 <blockquote>The syntax now is:</blockquote>
84 <blockquote><query> := "add" [ "distr" ]? [ <groups> |
85 <avar> ] "in" <query><br>
86 <groups> := <group> [ ";" <group> ]*<br>
87 <group> := <attribute> [ "," <attribute> ]*<br>
88 <attribute> := <value> "as" <path><br>
91 the query <b>add "1" as "a", "2" as "b" in subj "A"</b> gives the result
92 <b>"A" attr {"a"="1"; "b"="2"}</b> while<br>
93 the query <b>add "1" as "a"; "2" as "b" in subj "A"</b> gives the result
94 <b>"A" attr {"a"="1"}, {"b"="2"}</b>.<br>
97 <li>The new <b>align</b> operator takes an integer <i>i</i> (represented
98 as a string), a multiple string value <i>v</i> and returns the same <i>v</i>
99 where each string with length <i>n < i</i> is prefixed with <i>i - n</i>
100 spaces. The syntax of the add operator is:</li>
102 <blockquote><value> := "align" <string> "in" <value><br>
104 This operators aligns strings containing numbers so that their alphabetic
105 order agrees with their numeric order.<br>
109 <li>The <b>intersect</b> operator now intersects the attribute groups
110 of the mathing subject strings set-theoretically rather than making their
111 "Cartesian product". This semantics reduces the computational costs and makes
112 intersection the dual of union.</li>
115 <li>The <b>property</b> operator now accepts more than one <b>isfalse</b>
116 clause to increase the complexity of the constraint condition used to filter
117 the query results. This feature is exploited in the queries produced by the
118 <a href="implementation.html">HELM query generator</a>. <br>