XQuilla/docs/xqc-api/xqc-context-item_8c-example.html

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<div class="title">xqc-context-item.c</div> </div>
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<p>This example parses a document and sets it as the context item. It then executes an XQuery expression that navigates relative to the context item.</p>
<div class="fragment"><div class="line"><span class="preprocessor">#include &lt;<a class="code" href="xqilla-xqc_8h.html">xqilla/xqilla-xqc.h</a>&gt;</span></div>
<div class="line"></div>
<div class="line"><span class="keywordtype">int</span> main(<span class="keywordtype">int</span> argc, <span class="keywordtype">char</span> *argv[])</div>
<div class="line">{</div>
<div class="line"> <a name="_a0"></a><a class="code" href="structXQC__Implementation__s.html">XQC_Implementation</a> *impl;</div>
<div class="line"> <a name="_a1"></a><a class="code" href="structXQC__Expression__s.html">XQC_Expression</a> *expr;</div>
<div class="line"> <a name="_a2"></a><a class="code" href="structXQC__DynamicContext__s.html">XQC_DynamicContext</a> *context;</div>
<div class="line"> <a name="_a3"></a><a class="code" href="structXQC__Sequence__s.html">XQC_Sequence</a> *seq, *doc;</div>
<div class="line"> <a class="code" href="xqc_8h.html#aeb1ad206e9c38a7f84749cafe04d7a3f">XQC_Error</a> err;</div>
<div class="line"> <span class="keyword">const</span> <span class="keywordtype">char</span> *value;</div>
<div class="line"></div>
<div class="line"> <span class="comment">// XQilla specific way to create an XQC_Implementation struct</span></div>
<div class="line"> impl = <a name="a4"></a><a class="code" href="xqilla-xqc_8h.html#acd9659e93bbfafcd0cac9d7c4c12e13c">createXQillaXQCImplementation</a>(<a name="a5"></a><a class="code" href="xqc_8h.html#a8fbc00dfcf0a3527e0ccba36322e1c84">XQC_VERSION_NUMBER</a>);</div>
<div class="line"> <span class="keywordflow">if</span>(impl == 0) <span class="keywordflow">return</span> 1;</div>
<div class="line"></div>
<div class="line"> <span class="comment">// Parse an XQuery expression</span></div>
<div class="line"> err = impl-&gt;<a name="a6"></a><a class="code" href="structXQC__Implementation__s.html#a4f82aa0b0e5c675f95f6c78b3bf76216">prepare</a>(impl, <span class="stringliteral">&quot;foo/bar/@baz&quot;</span>, 0, &amp;expr);</div>
<div class="line"> <span class="keywordflow">if</span>(err != 0) <span class="keywordflow">goto</span> free_impl;</div>
<div class="line"></div>
<div class="line"> <span class="comment">// Parse a document</span></div>
<div class="line"> err = impl-&gt;<a name="a7"></a><a class="code" href="structXQC__Implementation__s.html#a1e3a2cd7fdb4becb469d179bcb4c2396">parse_document</a>(impl, <span class="stringliteral">&quot;&lt;foo&gt;&lt;bar baz=&#39;hello&#39;/&gt;&lt;/foo&gt;&quot;</span>, &amp;doc);</div>
<div class="line"> <span class="keywordflow">if</span>(err != 0) <span class="keywordflow">goto</span> free_expr;</div>
<div class="line"></div>
<div class="line"> <span class="comment">// Create a dynamic context</span></div>
<div class="line"> err = expr-&gt;<a name="a8"></a><a class="code" href="structXQC__Expression__s.html#a04be56651df9f3f47aecd99a0b0ad66e">create_context</a>(expr, &amp;context);</div>
<div class="line"> <span class="keywordflow">if</span>(err != 0) <span class="keywordflow">goto</span> free_doc;</div>
<div class="line"></div>
<div class="line"> <span class="comment">// Set the document as the context item</span></div>
<div class="line"> doc-&gt;<a name="a9"></a><a class="code" href="structXQC__Sequence__s.html#ab84594b06f7e69fd870c41f55ae5c6c6">next</a>(doc);</div>
<div class="line"> context-&gt;<a name="a10"></a><a class="code" href="structXQC__DynamicContext__s.html#a0c69d262bfe4fd038832db4e4db600af">set_context_item</a>(context, doc);</div>
<div class="line"></div>
<div class="line"> <span class="comment">// Execute the query</span></div>
<div class="line"> err = expr-&gt;<a name="a11"></a><a class="code" href="structXQC__Expression__s.html#a3181579fa2677d43c29efd31a649726c">execute</a>(expr, context, &amp;seq);</div>
<div class="line"> <span class="keywordflow">if</span>(err != 0) <span class="keywordflow">goto</span> free_context;</div>
<div class="line"></div>
<div class="line"> <span class="comment">// Iterate over the results, printing them</span></div>
<div class="line"> <span class="keywordflow">while</span>((err = seq-&gt;<a class="code" href="structXQC__Sequence__s.html#ab84594b06f7e69fd870c41f55ae5c6c6">next</a>(seq)) == <a name="a12"></a><a class="code" href="xqc_8h.html#aeb1ad206e9c38a7f84749cafe04d7a3fa975a11c6557d4d849e48f4034380a375">XQC_NO_ERROR</a>) {</div>
<div class="line"> seq-&gt;<a name="a13"></a><a class="code" href="structXQC__Sequence__s.html#a3bd3b6dab0c68652af816438407dd037">string_value</a>(seq, &amp;value);</div>
<div class="line"> printf(<span class="stringliteral">&quot;%s\n&quot;</span>, value);</div>
<div class="line"> }</div>
<div class="line"></div>
<div class="line"> <span class="keywordflow">if</span>(err == <a name="a14"></a><a class="code" href="xqc_8h.html#aeb1ad206e9c38a7f84749cafe04d7a3fadfd1d8eea45c90655b98cfd728bfee2e">XQC_END_OF_SEQUENCE</a>)</div>
<div class="line"> err = <a class="code" href="xqc_8h.html#aeb1ad206e9c38a7f84749cafe04d7a3fa975a11c6557d4d849e48f4034380a375">XQC_NO_ERROR</a>;</div>
<div class="line"></div>
<div class="line"> <span class="comment">// free everything</span></div>
<div class="line"> seq-&gt;<a name="a15"></a><a class="code" href="structXQC__Sequence__s.html#a13ab651edb4e0754cb8a032e2bce50b0">free</a>(seq);</div>
<div class="line">free_context:</div>
<div class="line"> context-&gt;<a name="a16"></a><a class="code" href="structXQC__DynamicContext__s.html#ad40117a7e2dd660ea7478c4cc5124eab">free</a>(context);</div>
<div class="line">free_doc:</div>
<div class="line"> doc-&gt;<a class="code" href="structXQC__Sequence__s.html#a13ab651edb4e0754cb8a032e2bce50b0">free</a>(doc);</div>
<div class="line">free_expr:</div>
<div class="line"> expr-&gt;<a name="a17"></a><a class="code" href="structXQC__Expression__s.html#a6aa28a94f0ff6732c26f131bbe4d44a9">free</a>(expr);</div>
<div class="line">free_impl:</div>
<div class="line"> impl-&gt;<a name="a18"></a><a class="code" href="structXQC__Implementation__s.html#afb636b6cbd236831652a518d9e71418d">free</a>(impl);</div>
<div class="line"></div>
<div class="line"> <span class="keywordflow">return</span> err;</div>
<div class="line">}</div>
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