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    <p>The attaributes containing the node's children depend on the type of syntax the node represents. Every node class also has a special <code>_fields</code> attribute, that lists the attribute names for the child nodes that class has. For instance, </p> <pre><code>&gt;&gt;&gt; ast.parse('5+a') &lt;_ast.Module object at 0x02C1F730&gt; &gt;&gt;&gt; ast.parse('5+a').body [&lt;_ast.Expr object at 0x02C1FF50&gt;] &gt;&gt;&gt; ast.parse('5+a').body[0] &lt;_ast.Expr object at 0x02C1FBF0&gt; &gt;&gt;&gt; ast.parse('5+a').body[0]._fields ('value',) &gt;&gt;&gt; ast.parse('5+a').body[0].value &lt;_ast.BinOp object at 0x02C1FF90&gt; &gt;&gt;&gt; ast.parse('5+a').body[0].value._fields ('left', 'op', 'right') &gt;&gt;&gt; ast.parse('5+a').body[0].value.left &lt;_ast.Num object at 0x02C1FB70&gt; </code></pre> <p>and so on.</p> <p><em>Edit, to clarify what's going on</em></p> <p>Before going any further, take a glance at the <a href="http://docs.python.org/library/ast.html#abstract-grammar" rel="nofollow">CPython Abstract Grammar</a></p> <p>Consider: </p> <pre><code>&gt;&gt;&gt; type(ast.parse('5+a')) &lt;class '_ast.Module'&gt; </code></pre> <p>In fact, if you look at the grammar, the first production rule is for Module. It appears to take a sequence of statements, as an argument called body. </p> <pre><code>&gt;&gt;&gt; ast.parse('5+a')._fields ('body',) &gt;&gt;&gt; ast.parse('5+a').body [&lt;_ast.Expr object at 0x02E965B0&gt;] </code></pre> <p>The <code>_fields</code> attribute of the AST is just "body", and the body attribute is a sequence of AST nodes. Back to the grammar, looking in the production rules for <code>stmt</code>, we see that <code>Expr</code> takes a single expr, named <code>value</code></p> <pre><code>&gt;&gt;&gt; ast.parse('5+a').body[0].value &lt;_ast.BinOp object at 0x02E96330&gt; </code></pre> <p>If we look up the definition for BinOp, we see that it takes 3 different arguments, left, op and right. You should be able to proceed from there, I hope.</p>
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    1. COthanks for your reply! However I haven't understood it yet properly... so node._fields will give the children of that particular node? (in form of a tupple?).... then what does body and value signify? thanks for your help!
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