Added test

doc/jsonpath

@@ -527,6 +527,51 @@ basic_json<Char,Alloc> json_query(const basic_json<Char,Alloc>&
 </tr>
 </tbody>
 </table>
+<h3 id="filter-expression">Filter expression</h3>
+<table>
+<thead>
+<tr>
+<th>Operator</th>
+<th>Description</th>
+</tr>
+</thead>
+<tbody>
+<tr>
+<td><code>==</code></td>
+<td>Left is equal to right </td>
+</tr>
+<tr>
+<td><code>!=</code></td>
+<td>Left is not equal to right</td>
+</tr>
+<tr>
+<td><code>&lt;</code></td>
+<td>Left is less than right</td>
+</tr>
+<tr>
+<td><code>&lt;=</code></td>
+<td>Left is less or equal to right</td>
+</tr>
+<tr>
+<td><code>&gt;</code></td>
+<td>Left is greater than right</td>
+</tr>
+<tr>
+<td><code>&gt;=</code></td>
+<td>Left is greater than or equal to right</td>
+</tr>
+<tr>
+<td><code>&amp;&amp;</code></td>
+<td>Left and right</td>
+</tr>
+<tr>
+<td>`</td>
+<td>`</td>
+<td>Left or right</td>
+</tr>
+</tbody>
+</table>
+<p>In this implementation, binary expressions must appear within parentheses.</p>
 <h3 id="examples">Examples</h3>
 <p>The examples below use the JSON text from <a href="http://goessner.net/articles/JsonPath/">Stefan Goessner&#39;s JsonPath</a> (store.json).</p>
 <pre><code>{ &quot;store&quot;: {
@@ -586,6 +631,11 @@ std::cout &lt;&lt; pretty_print(result) &lt;&lt; std::endl;
 </thead>
 <tbody>
 <tr>
+<td><code>$..book.length</code></td>
+<td>The number of books</td>
+<td><code>length</code> is a property of an array</td>
+</tr>
+<tr>
 <td><code>$.store.book[*].author</code></td>
 <td>All authors of books in the store</td>
 </tr>
@@ -646,10 +696,6 @@ std::cout &lt;&lt; pretty_print(result) &lt;&lt; std::endl;
 <td>Everything in the store.</td>
 </tr>
 <tr>
-<td><code>$..book.length</code></td>
-<td>The number of books</td>
-</tr>
-<tr>
 <td>`$.store.book[ ?((@.author == &#39;Nigel Rees&#39;)</td>
 <td>(@.author == &#39;Evelyn Waugh&#39;)) ].title`</td>
 <td>The titles of all books by Nigel Rees and Evelyn Waugh</td>

src/doc/Reference/jsonpath.md

@@ -25,6 +25,21 @@ JSONPath|	Description
 `?()`	|Applies a filter expression.
 `()`	|Filter expression.
 
+### Filter expression
+
+Operator|	Description
+--------|--------------------------------
+`==`	|Left is equal to right 
+`!=`	|Left is not equal to right
+`<`	    |Left is less than right
+`<=`	|Left is less or equal to right
+`>`	    |Left is greater than right
+`>=`	|Left is greater than or equal to right
+`&&`	|Left and right
+`||`	|Left or right
+
+In this implementation, binary expressions must appear within parentheses.
+
 ### Examples
 
 The examples below use the JSON text from [Stefan Goessner's JsonPath](http://goessner.net/articles/JsonPath/) (store.json).
@@ -84,6 +99,7 @@ A list of sample JSON paths and results follows.
 
 JSONPath |Result|Notes
 ---------|--------------------------------------------------------|------
+`$..book.length`	|The number of books|`length` is a property of an array
 `$.store.book[*].author`	|All authors of books in the store
 `$..author`	            |All authors
 `$.store.*`	            |Everything in the store, including books and a bicycle.
@@ -98,6 +114,5 @@ JSONPath |Result|Notes
 `$..book[?(@.isbn)]`	    |All books that have isbn number
 `$..book[?(@.price<10)]`	|All books that are cheaper than $10
 `$..*`	                |Everything in the store.
-`$..book.length`	|The number of books
 `$.store.book[ ?((@.author == 'Nigel Rees') || (@.author == 'Evelyn Waugh')) ].title`|The titles of all books by Nigel Rees and Evelyn Waugh
 

test_suite/src/jsonpath_tests.cpp

@@ -279,9 +279,11 @@ BOOST_AUTO_TEST_CASE(test_jsonpath_array_length)
     json result = json_query(root,"$..book.length");
 
 	std::cout << pretty_print(result) << std::endl;
+
+    BOOST_CHECK_EQUAL(1,result.size());
+    BOOST_CHECK_EQUAL(root["store"]["book"].size(),result[0].as<size_t>());
 }
 
-
 BOOST_AUTO_TEST_CASE(test_jsonpath_book_category)
 {
     json root = json::parse_string(jsonpath_fixture::book_text());