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| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h5 class="title"> |
| <a name="spirit.qi.reference.string.symbols"></a><a class="link" href="symbols.html" title="Symbols (symbols)">Symbols (<code class="computeroutput"><span class="identifier">symbols</span></code>)</a> |
| </h5></div></div></div> |
| <a name="spirit.qi.reference.string.symbols.description"></a><h6> |
| <a name="id949658"></a> |
| <a class="link" href="symbols.html#spirit.qi.reference.string.symbols.description">Description</a> |
| </h6> |
| <p> |
| The class <code class="computeroutput"><span class="identifier">symbols</span></code> implements |
| a symbol table: an associative container (or map) of key-value pairs |
| where the keys are strings. The <code class="computeroutput"><span class="identifier">symbols</span></code> |
| class can work efficiently with 8, 16, 32 and even 64 bit characters. |
| </p> |
| <p> |
| Traditionally, symbol table management is maintained separately outside |
| the grammar through semantic actions. Contrary to standard practice, |
| the Spirit symbol table class <code class="computeroutput"><span class="identifier">symbols</span></code> |
| is-a parser, an instance of which may be used anywhere in the grammar |
| specification. It is an example of a dynamic parser. A dynamic parser |
| is characterized by its ability to modify its behavior at run time. Initially, |
| an empty symbols object matches nothing. At any time, symbols may be |
| added, thus, dynamically altering its behavior. |
| </p> |
| <a name="spirit.qi.reference.string.symbols.header"></a><h6> |
| <a name="id949700"></a> |
| <a class="link" href="symbols.html#spirit.qi.reference.string.symbols.header">Header</a> |
| </h6> |
| <pre class="programlisting"><span class="comment">// forwards to <boost/spirit/home/qi/string/symbols.hpp> |
| </span><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">qi_symbols</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| </pre> |
| <p> |
| Also, see <a class="link" href="../../../structure/include.html" title="Include">Include Structure</a>. |
| </p> |
| <a name="spirit.qi.reference.string.symbols.namespace"></a><h6> |
| <a name="id949774"></a> |
| <a class="link" href="symbols.html#spirit.qi.reference.string.symbols.namespace">Namespace</a> |
| </h6> |
| <div class="informaltable"><table class="table"> |
| <colgroup><col></colgroup> |
| <thead><tr><th> |
| <p> |
| Name |
| </p> |
| </th></tr></thead> |
| <tbody> |
| <tr><td> |
| <p> |
| <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">qi</span><span class="special">::</span><span class="identifier">symbols</span></code> |
| </p> |
| </td></tr> |
| <tr><td> |
| <p> |
| <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">qi</span><span class="special">::</span><span class="identifier">tst</span></code> |
| </p> |
| </td></tr> |
| <tr><td> |
| <p> |
| <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">qi</span><span class="special">::</span><span class="identifier">tst_map</span></code> |
| </p> |
| </td></tr> |
| </tbody> |
| </table></div> |
| <a name="spirit.qi.reference.string.symbols.synopsis"></a><h6> |
| <a name="id949934"></a> |
| <a class="link" href="symbols.html#spirit.qi.reference.string.symbols.synopsis">Synopsis</a> |
| </h6> |
| <pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Char</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">T</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Lookup</span><span class="special">></span> |
| <span class="keyword">struct</span> <span class="identifier">symbols</span><span class="special">;</span> |
| </pre> |
| <a name="spirit.qi.reference.string.symbols.template_parameters"></a><h6> |
| <a name="id950012"></a> |
| <a class="link" href="symbols.html#spirit.qi.reference.string.symbols.template_parameters">Template |
| parameters</a> |
| </h6> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Parameter |
| </p> |
| </th> |
| <th> |
| <p> |
| Description |
| </p> |
| </th> |
| <th> |
| <p> |
| Default |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Char</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| The character type of the symbol strings. |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="keyword">char</span></code> |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">T</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| The data type associated with each symbol. |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">unused_type</span></code> |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Lookup</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| The symbol search implementation |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">tst</span><span class="special"><</span><span class="identifier">Char</span><span class="special">,</span> |
| <span class="identifier">T</span><span class="special">></span></code> |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <a name="spirit.qi.reference.string.symbols.model_of"></a><h6> |
| <a name="id950205"></a> |
| <a class="link" href="symbols.html#spirit.qi.reference.string.symbols.model_of">Model of</a> |
| </h6> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| <a class="link" href="../parser_concepts/primitiveparser.html" title="PrimitiveParser"><code class="computeroutput"><span class="identifier">PrimitiveParser</span></code></a> |
| </p></blockquote></div> |
| <div class="variablelist"> |
| <p class="title"><b>Notation</b></p> |
| <dl> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">Sym</span></code></span></dt> |
| <dd><p> |
| A <code class="computeroutput"><span class="identifier">symbols</span></code> type. |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">Char</span></code></span></dt> |
| <dd><p> |
| A character type. |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">T</span></code></span></dt> |
| <dd><p> |
| A data type. |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">sym</span></code>, <code class="computeroutput"><span class="identifier">sym2</span></code></span></dt> |
| <dd><p> |
| <code class="computeroutput"><span class="identifier">symbols</span></code> objects. |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">sseq</span></code></span></dt> |
| <dd><p> |
| An <a href="http://www.sgi.com/tech/stl/" target="_top">STL</a> container |
| of strings. |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">dseq</span></code></span></dt> |
| <dd><p> |
| An <a href="http://www.sgi.com/tech/stl/" target="_top">STL</a> container |
| of data with <code class="computeroutput"><span class="identifier">value_type</span></code> |
| <code class="computeroutput"><span class="identifier">T</span></code>. |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code></span></dt> |
| <dd><p> |
| A <a class="link" href="../basics.html#spirit.qi.reference.basics.string">String</a>. |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">d1</span></code>...<code class="computeroutput"><span class="identifier">dN</span></code></span></dt> |
| <dd><p> |
| Objects of type <code class="computeroutput"><span class="identifier">T</span></code>. |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">f</span></code></span></dt> |
| <dd><p> |
| A callable function or function object. |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">f</span></code>, <code class="computeroutput"><span class="identifier">l</span></code></span></dt> |
| <dd><p> |
| <code class="computeroutput"><span class="identifier">ForwardIterator</span></code> |
| first/last pair. |
| </p></dd> |
| </dl> |
| </div> |
| <a name="spirit.qi.reference.string.symbols.expression_semantics"></a><h6> |
| <a name="id950529"></a> |
| <a class="link" href="symbols.html#spirit.qi.reference.string.symbols.expression_semantics">Expression |
| Semantics</a> |
| </h6> |
| <p> |
| Semantics of an expression is defined only where it differs from, or |
| is not defined in <a class="link" href="../parser_concepts/primitiveparser.html" title="PrimitiveParser"><code class="computeroutput"><span class="identifier">PrimitiveParser</span></code></a>. |
| </p> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Expression |
| </p> |
| </th> |
| <th> |
| <p> |
| Semantics |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Sym</span><span class="special">()</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Construct an empty symbols. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Sym</span><span class="special">(</span><span class="identifier">sym2</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Copy construct a symbols from <code class="computeroutput"><span class="identifier">sym2</span></code> |
| (Another <code class="computeroutput"><span class="identifier">symbols</span></code> |
| object). |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Sym</span><span class="special">(</span><span class="identifier">sseq</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Construct symbols from <code class="computeroutput"><span class="identifier">sseq</span></code> |
| (An <a href="http://www.sgi.com/tech/stl/" target="_top">STL</a> container |
| of strings). |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Sym</span><span class="special">(</span><span class="identifier">sseq</span><span class="special">,</span> |
| <span class="identifier">dseq</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Construct symbols from <code class="computeroutput"><span class="identifier">sseq</span></code> |
| and <code class="computeroutput"><span class="identifier">dseq</span></code> (An |
| <a href="http://www.sgi.com/tech/stl/" target="_top">STL</a> container |
| of strings and an <a href="http://www.sgi.com/tech/stl/" target="_top">STL</a> |
| container of data with <code class="computeroutput"><span class="identifier">value_type</span></code> |
| <code class="computeroutput"><span class="identifier">T</span></code>). |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">sym</span> <span class="special">=</span> |
| <span class="identifier">sym2</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Assign <code class="computeroutput"><span class="identifier">sym2</span></code> |
| to <code class="computeroutput"><span class="identifier">sym</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">sym</span> <span class="special">=</span> |
| <span class="identifier">s1</span><span class="special">,</span> |
| <span class="identifier">s2</span><span class="special">,</span> |
| <span class="special">...,</span> <span class="identifier">sN</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Assign one or more symbols (<code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code>) to <code class="computeroutput"><span class="identifier">sym</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">sym</span> <span class="special">+=</span> |
| <span class="identifier">s1</span><span class="special">,</span> |
| <span class="identifier">s2</span><span class="special">,</span> |
| <span class="special">...,</span> <span class="identifier">sN</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Add one or more symbols (<code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code>) to <code class="computeroutput"><span class="identifier">sym</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">add</span><span class="special">(</span><span class="identifier">s1</span><span class="special">)(</span><span class="identifier">s2</span><span class="special">)...(</span><span class="identifier">sN</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Add one or more symbols (<code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code>) to <code class="computeroutput"><span class="identifier">sym</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">add</span><span class="special">(</span><span class="identifier">s1</span><span class="special">,</span> |
| <span class="identifier">d1</span><span class="special">)(</span><span class="identifier">s2</span><span class="special">,</span> |
| <span class="identifier">d2</span><span class="special">)...(</span><span class="identifier">sN</span><span class="special">,</span> |
| <span class="identifier">dN</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Add one or more symbols (<code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code>) with associated data |
| (<code class="computeroutput"><span class="identifier">d1</span></code>...<code class="computeroutput"><span class="identifier">dN</span></code>) to <code class="computeroutput"><span class="identifier">sym</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">sym</span> <span class="special">-=</span> |
| <span class="identifier">s1</span><span class="special">,</span> |
| <span class="identifier">s2</span><span class="special">,</span> |
| <span class="special">...,</span> <span class="identifier">sN</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Remove one or more symbols (<code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code>) from <code class="computeroutput"><span class="identifier">sym</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">remove</span><span class="special">(</span><span class="identifier">s1</span><span class="special">)(</span><span class="identifier">s2</span><span class="special">)...(</span><span class="identifier">sN</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Remove one or more symbols (<code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code>) from <code class="computeroutput"><span class="identifier">sym</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">clear</span><span class="special">()</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Erase all of the symbols in <code class="computeroutput"><span class="identifier">sym</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">at</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Return a reference to the object associated with symbol, <code class="computeroutput"><span class="identifier">s</span></code>. If <code class="computeroutput"><span class="identifier">sym</span></code> |
| does not already contain such an object, <code class="computeroutput"><span class="identifier">at</span></code> |
| inserts the default object <code class="computeroutput"><span class="identifier">T</span><span class="special">()</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">find</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Return a pointer to the object associated with symbol, <code class="computeroutput"><span class="identifier">s</span></code>. If <code class="computeroutput"><span class="identifier">sym</span></code> |
| does not already contain such an object, <code class="computeroutput"><span class="identifier">find</span></code> |
| returns a null pointer. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">prefix_find</span><span class="special">(</span><span class="identifier">f</span><span class="special">,</span> |
| <span class="identifier">l</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Return a pointer to the object associated with longest symbol |
| that matches the beginning of the range <code class="computeroutput"><span class="special">[</span><span class="identifier">f</span><span class="special">,</span> |
| <span class="identifier">l</span><span class="special">)</span></code>, |
| and updates <code class="computeroutput"><span class="identifier">f</span></code> |
| to point to one past the end of that match. If no symbol matches, |
| then return a null pointer, and <code class="computeroutput"><span class="identifier">f</span></code> |
| is unchanged. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">for_each</span><span class="special">(</span><span class="identifier">f</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| For each symbol in <code class="computeroutput"><span class="identifier">sym</span></code>, |
| <code class="computeroutput"><span class="identifier">s</span></code>, a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_string</span><span class="special"><</span><span class="identifier">Char</span><span class="special">></span></code> |
| with associated data, <code class="computeroutput"><span class="identifier">d</span></code>, |
| an object of type <code class="computeroutput"><span class="identifier">T</span></code>, |
| invoke <code class="computeroutput"><span class="identifier">f</span><span class="special">(</span><span class="identifier">s</span><span class="special">,</span> |
| <span class="identifier">d</span><span class="special">)</span></code>. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <a name="spirit.qi.reference.string.symbols.attributes"></a><h6> |
| <a name="id951758"></a> |
| <a class="link" href="symbols.html#spirit.qi.reference.string.symbols.attributes">Attributes</a> |
| </h6> |
| <p> |
| The attribute of <code class="computeroutput"><span class="identifier">symbol</span><span class="special"><</span><span class="identifier">Char</span><span class="special">,</span> <span class="identifier">T</span><span class="special">></span></code> is <code class="computeroutput"><span class="identifier">T</span></code>. |
| </p> |
| <a name="spirit.qi.reference.string.symbols.complexity"></a><h6> |
| <a name="id951808"></a> |
| <a class="link" href="symbols.html#spirit.qi.reference.string.symbols.complexity">Complexity</a> |
| </h6> |
| <p> |
| The default implementation uses a Ternary Search Tree (TST) with complexity: |
| </p> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| O(log n+k) |
| </p></blockquote></div> |
| <p> |
| Where k is the length of the string to be searched in a TST with n strings. |
| </p> |
| <p> |
| TSTs are faster than hashing for many typical search problems especially |
| when the search interface is iterator based. TSTs are many times faster |
| than hash tables for unsuccessful searches since mismatches are discovered |
| earlier after examining only a few characters. Hash tables always examine |
| an entire key when searching. |
| </p> |
| <p> |
| An alternative implementation uses a hybrid hash-map front end (for the |
| first character) plus a TST: <code class="computeroutput"><span class="identifier">tst_map</span></code>. |
| This gives us a complexity of |
| </p> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| O(1 + log n+k-1) |
| </p></blockquote></div> |
| <p> |
| This is found to be significantly faster than plain TST, albeit with |
| a bit more memory usage requirements (each slot in the hash-map is a |
| TST node). If you require a lot of symbols to be searched, use the <code class="computeroutput"><span class="identifier">tst_map</span></code> implementation. This can be |
| done by using <code class="computeroutput"><span class="identifier">tst_map</span></code> |
| as the third template parameter to the symbols class: |
| </p> |
| <pre class="programlisting"><span class="identifier">symbols</span><span class="special"><</span><span class="identifier">Char</span><span class="special">,</span> <span class="identifier">T</span><span class="special">,</span> <span class="identifier">tst_map</span><span class="special"><</span><span class="identifier">Char</span><span class="special">,</span> <span class="identifier">T</span><span class="special">></span> <span class="special">></span> <span class="identifier">sym</span><span class="special">;</span> |
| </pre> |
| <a name="spirit.qi.reference.string.symbols.example"></a><h6> |
| <a name="id951940"></a> |
| <a class="link" href="symbols.html#spirit.qi.reference.string.symbols.example">Example</a> |
| </h6> |
| <div class="note"><table border="0" summary="Note"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../images/note.png"></td> |
| <th align="left">Note</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| The test harness for the example(s) below is presented in the <a class="link" href="../basics.html#spirit.qi.reference.basics.examples">Basics Examples</a> |
| section. |
| </p></td></tr> |
| </table></div> |
| <p> |
| Some using declarations: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">qi</span><span class="special">::</span><span class="identifier">symbols</span><span class="special">;</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| Symbols with data: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="identifier">symbols</span><span class="special"><</span><span class="keyword">char</span><span class="special">,</span> <span class="keyword">int</span><span class="special">></span> <span class="identifier">sym</span><span class="special">;</span> |
| |
| <span class="identifier">sym</span><span class="special">.</span><span class="identifier">add</span> |
| <span class="special">(</span><span class="string">"Apple"</span><span class="special">,</span> <span class="number">1</span><span class="special">)</span> |
| <span class="special">(</span><span class="string">"Banana"</span><span class="special">,</span> <span class="number">2</span><span class="special">)</span> |
| <span class="special">(</span><span class="string">"Orange"</span><span class="special">,</span> <span class="number">3</span><span class="special">)</span> |
| <span class="special">;</span> |
| |
| <span class="keyword">int</span> <span class="identifier">i</span><span class="special">;</span> |
| <span class="identifier">test_parser_attr</span><span class="special">(</span><span class="string">"Banana"</span><span class="special">,</span> <span class="identifier">sym</span><span class="special">,</span> <span class="identifier">i</span><span class="special">);</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">i</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| When <code class="computeroutput"><span class="identifier">symbols</span></code> is used |
| for case-insensitive parsing (in a <a class="link" href="../directive/no_case.html" title="Inhibiting Case Sensitivity (no_case[])"><code class="computeroutput"><span class="identifier">no_case</span></code></a> directive), added symbol |
| strings should be in lowercase. Symbol strings containing one or more |
| uppercase characters will not match any input when symbols is used in |
| a <code class="computeroutput"><span class="identifier">no_case</span></code> directive. |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="identifier">symbols</span><span class="special"><</span><span class="keyword">char</span><span class="special">,</span> <span class="keyword">int</span><span class="special">></span> <span class="identifier">sym</span><span class="special">;</span> |
| |
| <span class="identifier">sym</span><span class="special">.</span><span class="identifier">add</span> |
| <span class="special">(</span><span class="string">"apple"</span><span class="special">,</span> <span class="number">1</span><span class="special">)</span> <span class="comment">// symbol strings are added in lowercase... |
| </span> <span class="special">(</span><span class="string">"banana"</span><span class="special">,</span> <span class="number">2</span><span class="special">)</span> |
| <span class="special">(</span><span class="string">"orange"</span><span class="special">,</span> <span class="number">3</span><span class="special">)</span> |
| <span class="special">;</span> |
| |
| <span class="keyword">int</span> <span class="identifier">i</span><span class="special">;</span> |
| <span class="comment">// ...because sym is used for case-insensitive parsing |
| </span><span class="identifier">test_parser_attr</span><span class="special">(</span><span class="string">"Apple"</span><span class="special">,</span> <span class="identifier">no_case</span><span class="special">[</span> <span class="identifier">sym</span> <span class="special">],</span> <span class="identifier">i</span><span class="special">);</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">i</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> |
| <span class="identifier">test_parser_attr</span><span class="special">(</span><span class="string">"ORANGE"</span><span class="special">,</span> <span class="identifier">no_case</span><span class="special">[</span> <span class="identifier">sym</span> <span class="special">],</span> <span class="identifier">i</span><span class="special">);</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">i</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> |
| </pre> |
| <p> |
| </p> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2001-2010 Joel de Guzman, Hartmut Kaiser<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) |
| </p> |
| </div></td> |
| </tr></table> |
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