more dfn

2026-06-05 23:10:17 +00:00 · 2009-06-08 21:46:14 -04:00
parent 7d02bae3a2
commit b32230f7ec
1 changed files with 106 additions and 106 deletions
@@ -45,23 +45,23 @@ td a:link, td a:visited{border:0}
 <tr><th>&#x2460;
 <td>to initialize an instance
 <td><code class=pp>x = MyClass()</code>
-<td><code class=pp>x.__init__()</code>
+<td><code class=pp>x.<dfn>__init__</dfn>()</code>
 <tr><th>&#x2461;
 <td>the &#8220;official&#8221; representation as a string
-<td><code class=pp>repr(x)</code>
-<td><code class=pp>x.__repr__()</code>
+<td><code class=pp><dfn>repr</dfn>(x)</code>
+<td><code class=pp>x.<dfn>__repr__</dfn>()</code>
 <tr><th>&#x2462;
 <td>the &#8220;informal&#8221; value as a string
-<td><code class=pp>str(x)</code>
-<td><code class=pp>x.__str__()</code>
+<td><code class=pp><dfn>str</dfn>(x)</code>
+<td><code class=pp>x.<dfn>__str__</dfn>()</code>
 <tr><th>&#x2463;
 <td>the &#8220;informal&#8221; value as a byte array
-<td><code class=pp>bytes(x)</code>
-<td><code class=pp>x.__bytes__()</code>
+<td><code class=pp><dfn>bytes</dfn>(x)</code>
+<td><code class=pp>x.<dfn>__bytes__</dfn>()</code>
 <tr><th>&#x2464;
 <td>the value as a formatted string
 <td><code class=pp>format(x)</code>
-<td><code class=pp>x.__format__(<var>format_spec</var>)</code>
+<td><code class=pp>x.<dfn>__format__</dfn>(<var>format_spec</var>)</code>
 </table>
 <ol>
 <li>The <code>__init__()</code> method is called <em>after</em> the instance is created. If you want to control the actual creation process, use <a href=#esoterica>the <code>__new__()</code> method</a>.
@@ -82,16 +82,16 @@ td a:link, td a:visited{border:0}
 <th>And Python Calls&hellip;
 <tr><th>&#x2460;
 <td>to iterate through a sequence
-<td><code class=pp>iter(seq)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__iter__><code>seq.__iter__()</code></a>
+<td><code class=pp><dfn>iter</dfn>(seq)</code>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__iter__><code>seq.<dfn>__iter__</dfn>()</code></a>
 <tr><th>&#x2461;
 <td>to get the next value from an iterator
-<td><code class=pp>next(seq)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__next__><code>seq.__next__()</code></a>
+<td><code class=pp><dfn>next</dfn>(seq)</code>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__next__><code>seq.<dfn>__next__</dfn>()</code></a>
 <tr><th>&#x2462;
 <td>to create an iterator in reverse order
-<td><code class=pp>reversed(seq)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__reversed__><code>seq.__reversed__()</code></a>
+<td><code class=pp><dfn>reversed</dfn>(seq)</code>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__reversed__><code>seq.<dfn>__reversed__</dfn>()</code></a>
 </table>
 <ol>
 <li>The <code>__iter__()</code> method is called whenever you create a new iterator. It&#8217;s a good place to initialize the iterator with initial values.
@@ -111,23 +111,23 @@ td a:link, td a:visited{border:0}
 <tr><th>&#x2460;
 <td>to get a computed attribute (unconditionally)
 <td><code class=pp>x.my_property</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__getattribute__><code>x.__getattribute__(<var>'my_property'</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__getattribute__><code>x.<dfn>__getattribute__</dfn>(<var>'my_property'</var>)</code></a>
 <tr><th>&#x2461;
 <td>to get a computed attribute (fallback)
 <td><code class=pp>x.my_property</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__getattr__><code>x.__getattr__(<var>'my_property'</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__getattr__><code>x.<dfn>__getattr__</dfn>(<var>'my_property'</var>)</code></a>
 <tr><th>&#x2462;
 <td>to set an attribute
 <td><code class=pp>x.my_property = value</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__setattr__><code>x.__setattr__(<var>'my_property'</var>, <var>value</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__setattr__><code>x.<dfn>__setattr__</dfn>(<var>'my_property'</var>, <var>value</var>)</code></a>
 <tr><th>&#x2463;
 <td>to delete an attribute
 <td><code class=pp>del x.my_property</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__delattr__><code>x.__delattr__(<var>'my_property'</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__delattr__><code>x.<dfn>__delattr__</dfn>(<var>'my_property'</var>)</code></a>
 <tr><th>&#x2464;
 <td>to list all attributes and methods
 <td><code class=pp>dir(x)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__dir__><code>x.__dir__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__dir__><code>x.<dfn>__dir__</dfn>()</code></a>
 </table>
 <ol>
 <li>If your class defines a <code>__getattribute__()</code> method, Python will call it on <em>every reference to any attribute or method name</em> (except special method names, since that would cause an unpleasant infinite loop).
@@ -217,10 +217,10 @@ AttributeError</samp></pre>
 <tr><th>
 <td>to &#8220;call&#8221; an instance like a function
 <td><code class=pp>my_instance()</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__call__><code>my_instance.__call__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__call__><code>my_instance.<dfn>__call__</dfn>()</code></a>
 </table>

-<p>The <a href=http://docs.python.org/3.0/library/zipfile.html><code>zipfile</code> module</a> uses this to define a class that can decrypt an encrypted zip file with a given password. The zip decryption algorithm requires you to store state during decryption. Defining the decryptor as a class allows you to maintain this state within a single instance of the decryptor class.  The state is initialized in the <code>__init__()</code> method and updated as the file is decrypted. But since the class is also &#8220;callable&#8221; like a function, you can pass the instance as the first argument of the <code>map()</code> function, like so:
+<p>The <a href=http://docs.python.org/3.0/library/zipfile.html><code>zipfile</code> module</a> uses this to define a class that can <dfn>decrypt</dfn> an <dfn>encrypted</dfn> <dfn>zip</dfn> file with a given password. The zip <dfn>decryption</dfn> algorithm requires you to store state during decryption. Defining the decryptor as a class allows you to maintain this state within a single instance of the decryptor class.  The state is initialized in the <code>__init__()</code> method and updated as the file is <dfn>decrypted</dfn>. But since the class is also &#8220;callable&#8221; like a function, you can pass the instance as the first argument of the <code>map()</code> function, like so:

 <pre><code class=pp># excerpt from zipfile.py
 class _ZipDecrypter:
@@ -264,12 +264,12 @@ bytes = zef_file.read(12)
 <th>And Python Calls&hellip;
 <tr><th>
 <td>the length of a sequence
-<td><code class=pp>len(seq)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__len__><code>seq.__len__()</code></a>
+<td><code class=pp><dfn>len</dfn>(seq)</code>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__len__><code>seq.<dfn>__len__</dfn>()</code></a>
 <tr><th>
 <td>to know whether a sequence contains a specific value
 <td><code class=pp>x in seq</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__contains__><code>seq.__contains__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__contains__><code>seq.<dfn>__contains__</dfn>(<var>x</var>)</code></a>
 </table>

 <p id=acts-like-list-example>The <a href=http://docs.python.org/3.0/library/cgi.html><code>cgi</code> module</a> uses these methods in its <code>FieldStorage</code> class, which represents all of the form fields or query parameters submitted to a dynamic web page.
@@ -311,19 +311,19 @@ class FieldStorage:
 <tr><th>
 <td>to get a value by its key
 <td><code class=pp>x[key]</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__getitem__><code>x.__getitem__(<var>'key'</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__getitem__><code>x.<dfn>__getitem__</dfn>(<var>'key'</var>)</code></a>
 <tr><th>
 <td>to set a value by its key
 <td><code class=pp>x[key] = value</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__setitem__><code>x.__setitem__(<var>'key'</var>, <var>value</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__setitem__><code>x.<dfn>__setitem__</dfn>(<var>'key'</var>, <var>value</var>)</code></a>
 <tr><th>
 <td>to delete a key-value pair
 <td><code class=pp>del x[key]</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__delitem__><code>x.__delitem__(<var>'key'</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__delitem__><code>x.<dfn>__delitem__</dfn>(<var>'key'</var>)</code></a>
 <tr><th>
 <td>to provide a default value for missing keys
 <td><code class=pp>x[nonexistent_key]</code>
-<td><a href=http://docs.python.org/3.0/library/collections.html#collections.defaultdict.__missing__><code>x.__missing__(<var>'nonexistent_key'</var>)</code></a>
+<td><a href=http://docs.python.org/3.0/library/collections.html#collections.defaultdict.__missing__><code>x.<dfn>__missing__</dfn>(<var>'nonexistent_key'</var>)</code></a>
 </table>

 <p>The <a href=#acts-like-list-example><code>FieldStorage</code> class</a> from the <a href=http://docs.python.org/3.0/library/cgi.html><code>cgi</code> module</a> also defines these special methods, which means you can do things like this:
@@ -358,7 +358,7 @@ class FieldStorage:

 <h2 id=acts-like-number>Classes That Act Like Numbers</h2>

-<p>Using the appropriate special methods, you can define your own classes that act like numbers. That is, you can add them, subtract them, and perform other mathematical operations on them. This is how <a href=advanced-classes.html#implementing-fractions>fractions are implemented</a> &mdash; the <code>Fraction</code> class implements these special methods, then you can do things like this:
+<p>Using the appropriate special methods, you can define your own classes that act like numbers. That is, you can add them, subtract them, and perform other mathematical operations on them. This is how <a href=advanced-classes.html#implementing-fractions><dfn>fractions</dfn> are implemented</a> &mdash; the <code><dfn>Fraction</dfn></code> class implements these special methods, then you can do things like this:

 <pre class=screen>
 <samp class=p>>>> </samp><kbd>from fractions import Fraction</kbd>
@@ -376,55 +376,55 @@ class FieldStorage:
 <tr><th>
 <td>addition
 <td><code class=pp>x + y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__add__><code>x.__add__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__add__><code>x.<dfn>__add__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>subtraction
 <td><code class=pp>x - y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__sub__><code>x.__sub__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__sub__><code>x.<dfn>__sub__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>multiplication
 <td><code class=pp>x * y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__mul__><code>x.__mul__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__mul__><code>x.<dfn>__mul__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>division
 <td><code class=pp>x / y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__truediv__><code>x.__truediv__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__truediv__><code>x.<dfn>__truediv__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>floor division
 <td><code class=pp>x // y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__floordiv__><code>x.__floordiv__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__floordiv__><code>x.<dfn>__floordiv__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>modulo (remainder)
 <td><code class=pp>x % y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__mod__><code>x.__mod__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__mod__><code>x.<dfn>__mod__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>floor division <i class=baa>&amp;</i> modulo
 <td><code class=pp>divmod(x, y)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__divmod__><code>x.__divmod__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__divmod__><code>x.<dfn>__divmod__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>raise to power
 <td><code class=pp>x ** y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__pow__><code>x.__pow__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__pow__><code>x.<dfn>__pow__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>left bit-shift
 <td><code class=pp>x &lt;&lt; y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__lshift__><code>x.__lshift__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__lshift__><code>x.<dfn>__lshift__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>right bit-shift
 <td><code class=pp>x >> y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rshift__><code>x.__rshift__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rshift__><code>x.<dfn>__rshift__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>bitwise <code>and</code>
 <td><code class=pp>x &amp; y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__and__><code>x.__and__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__and__><code>x.<dfn>__and__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>bitwise <code>xor</code>
 <td><code class=pp>x ^ y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__xor__><code>x.__xor__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__xor__><code>x.<dfn>__xor__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>bitwise <code>or</code>
 <td><code class=pp>x | y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__or__><code>x.__or__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__or__><code>x.<dfn>__or__</dfn>(<var>y</var>)</code></a>
 </table>

 <p>That&#8217;s all well and good if <var>x</var> is an instance of a class that implements those methods. But what if it doesn&#8217;t implement one of them? Or worse, what if it implements it, but it can&#8217;t handle certain kinds of arguments? For example:
@@ -454,55 +454,55 @@ class FieldStorage:
 <tr><th>
 <td>addition
 <td><code class=pp>x + y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__radd__><code>y.__radd__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__radd__><code>y.<dfn>__radd__</dfn>(<var>x</var>)</code></a>
 <tr><th>
 <td>subtraction
 <td><code class=pp>x - y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rsub__><code>y.__rsub__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rsub__><code>y.<dfn>__rsub__</dfn>(<var>x</var>)</code></a>
 <tr><th>
 <td>multiplication
 <td><code class=pp>x * y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rmul__><code>y.__rmul__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rmul__><code>y.<dfn>__rmul__</dfn>(<var>x</var>)</code></a>
 <tr><th>
 <td>division
 <td><code class=pp>x / y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rtruediv__><code>y.__rtruediv__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rtruediv__><code>y.<dfn>__rtruediv__</dfn>(<var>x</var>)</code></a>
 <tr><th>
 <td>floor division
 <td><code class=pp>x // y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rfloordiv__><code>y.__rfloordiv__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rfloordiv__><code>y.<dfn>__rfloordiv__</dfn>(<var>x</var>)</code></a>
 <tr><th>
 <td>modulo (remainder)
 <td><code class=pp>x % y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rmod__><code>y.__rmod__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rmod__><code>y.<dfn>__rmod__</dfn>(<var>x</var>)</code></a>
 <tr><th>
 <td>floor division <i class=baa>&amp;</i> modulo
 <td><code class=pp>divmod(x, y)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rdivmod__><code>y.__rdivmod__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rdivmod__><code>y.<dfn>__rdivmod__</dfn>(<var>x</var>)</code></a>
 <tr><th>
 <td>raise to power
 <td><code class=pp>x ** y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rpow__><code>y.__rpow__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rpow__><code>y.<dfn>__rpow__</dfn>(<var>x</var>)</code></a>
 <tr><th>
 <td>left bit-shift
 <td><code class=pp>x &lt;&lt; y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rlshift__><code>y.__rlshift__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rlshift__><code>y.<dfn>__rlshift__</dfn>(<var>x</var>)</code></a>
 <tr><th>
 <td>right bit-shift
 <td><code class=pp>x >> y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rrshift__><code>y.__rrshift__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rrshift__><code>y.<dfn>__rrshift__</dfn>(<var>x</var>)</code></a>
 <tr><th>
 <td>bitwise <code>and</code>
 <td><code class=pp>x &amp; y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rand__><code>y.__rand__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rand__><code>y.<dfn>__rand__</dfn>(<var>x</var>)</code></a>
 <tr><th>
 <td>bitwise <code>xor</code>
 <td><code class=pp>x ^ y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rxor__><code>y.__rxor__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__rxor__><code>y.<dfn>__rxor__</dfn>(<var>x</var>)</code></a>
 <tr><th>
 <td>bitwise <code>or</code>
 <td><code class=pp>x | y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ror__><code>y.__ror__(<var>x</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ror__><code>y.<dfn>__ror__</dfn>(<var>x</var>)</code></a>
 </table>

 <p>But wait! There&#8217;s more! If you&#8217;re doing &#8220;in-place&#8221; operations, like <code>x /= 3</code>, there are even more special methods you can define.
@@ -515,51 +515,51 @@ class FieldStorage:
 <tr><th>
 <td>in-place addition
 <td><code class=pp>x += y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__iadd__><code>x.__iadd__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__iadd__><code>x.<dfn>__iadd__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>in-place subtraction
 <td><code class=pp>x -= y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__isub__><code>x.__isub__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__isub__><code>x.<dfn>__isub__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>in-place multiplication
 <td><code class=pp>x *= y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__imul__><code>x.__imul__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__imul__><code>x.<dfn>__imul__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>in-place division
 <td><code class=pp>x /= y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__itruediv__><code>x.__itruediv__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__itruediv__><code>x.<dfn>__itruediv__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>in-place floor division
 <td><code class=pp>x //= y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ifloordiv__><code>x.__ifloordiv__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ifloordiv__><code>x.<dfn>__ifloordiv__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>in-place modulo
 <td><code class=pp>x %= y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__imod__><code>x.__imod__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__imod__><code>x.<dfn>__imod__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>in-place raise to power
 <td><code class=pp>x **= y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ipow__><code>x.__ipow__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ipow__><code>x.<dfn>__ipow__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>in-place left bit-shift
 <td><code class=pp>x &lt;&lt;= y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ilshift__><code>x.__ilshift__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ilshift__><code>x.<dfn>__ilshift__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>in-place right bit-shift
 <td><code class=pp>x >>= y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__irshift__><code>x.__irshift__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__irshift__><code>x.<dfn>__irshift__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>in-place bitwise <code>and</code>
 <td><code class=pp>x &amp;= y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__iand__><code>x.__iand__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__iand__><code>x.<dfn>__iand__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>in-place bitwise <code>xor</code>
 <td><code class=pp>x ^= y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ixor__><code>x.__ixor__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ixor__><code>x.<dfn>__ixor__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>in-place bitwise <code>or</code>
 <td><code class=pp>x |= y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ior__><code>x.__ior__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ior__><code>x.<dfn>__ior__</dfn>(<var>y</var>)</code></a>
 </table>

 <p>Note: for the most part, the in-place operation methods are not required. If you don&#8217;t define an in-place method for a particular operation, Python will try the methods. For example, to execute the expression <code>x /= y</code>, Python will:
@@ -582,55 +582,55 @@ class FieldStorage:
 <tr><th>
 <td>negative number
 <td><code class=pp>-x</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__neg__><code>x.__neg__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__neg__><code>x.<dfn>__neg__</dfn>()</code></a>
 <tr><th>
 <td>positive number
 <td><code class=pp>+x</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__pos__><code>x.__pos__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__pos__><code>x.<dfn>__pos__</dfn>()</code></a>
 <tr><th>
 <td>absolute value
 <td><code class=pp>abs(x)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__abs__><code>x.__abs__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__abs__><code>x.<dfn>__abs__</dfn>()</code></a>
 <tr><th>
 <td>inverse
 <td><code class=pp>~x</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__invert__><code>x.__invert__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__invert__><code>x.<dfn>__invert__</dfn>()</code></a>
 <tr><th>
 <td>complex number
 <td><code class=pp>complex(x)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__complex__><code>x.__complex__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__complex__><code>x.<dfn>__complex__</dfn>()</code></a>
 <tr><th>
 <td>integer
 <td><code class=pp>int(x)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__int__><code>x.__int__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__int__><code>x.<dfn>__int__</dfn>()</code></a>
 <tr><th>
 <td>floating point number
 <td><code class=pp>float(x)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__float__><code>x.__float__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__float__><code>x.<dfn>__float__</dfn>()</code></a>
 <tr><th>
 <td>number rounded to nearest integer
 <td><code class=pp>round(x)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__round__><code>x.__round__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__round__><code>x.<dfn>__round__</dfn>()</code></a>
 <tr><th>
 <td>number rounded to nearest <var>n</var> digits
 <td><code class=pp>round(x, n)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__round__><code>x.__round__(n)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__round__><code>x.<dfn>__round__</dfn>(n)</code></a>
 <tr><th>
 <td>smallest integer <code>>= x</code>
 <td><code class=pp>math.ceil(x)</code>
-<td><a href=http://docs.python.org/3.0/library/math.html#math.ceil><code>x.__ceil__()</code></a>
+<td><a href=http://docs.python.org/3.0/library/math.html#math.ceil><code>x.<dfn>__ceil__</dfn>()</code></a>
 <tr><th>
 <td>largest integer <code>&lt;= x</code>
 <td><code class=pp>math.floor(x)</code>
-<td><a href=http://docs.python.org/3.0/library/math.html#math.floor><code>x.__floor__()</code></a>
+<td><a href=http://docs.python.org/3.0/library/math.html#math.floor><code>x.<dfn>__floor__</dfn>()</code></a>
 <tr><th>
 <td>truncate <code>x</code> to nearest integer toward <code>0</code>
 <td><code class=pp>math.trunc(x)</code>
-<td><a href=http://docs.python.org/3.0/library/math.html#math.trunc><code>x.__trunc__()</code></a>
+<td><a href=http://docs.python.org/3.0/library/math.html#math.trunc><code>x.<dfn>__trunc__</dfn>()</code></a>
 <tr><th><a href=http://www.python.org/dev/peps/pep-0357/>PEP 357</a>
 <td>number as a list index
 <td><code class=pp>a_list[<var>x</var>]</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__index__><code>x.__index__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__index__><code>x.<dfn>__index__</dfn>()</code></a>
 </table>

 <h2 id=rich-comparisons>Classes That Can Be Compared</h2>
@@ -645,31 +645,31 @@ class FieldStorage:
 <tr><th>
 <td>equality
 <td><code class=pp>x == y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__eq__><code>x.__eq__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__eq__><code>x.<dfn>__eq__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>inequality
 <td><code class=pp>x != y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ne__><code>x.__ne__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ne__><code>x.<dfn>__ne__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>less than
 <td><code class=pp>x &lt; y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__lt__><code>x.__lt__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__lt__><code>x.<dfn>__lt__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>less than or equal to
 <td><code class=pp>x &lt;= y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__le__><code>x.__le__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__le__><code>x.<dfn>__le__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>greater than
 <td><code class=pp>x >  y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__gt__><code>x.__gt__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__gt__><code>x.<dfn>__gt__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>greater than or equal to
 <td><code class=pp>x >= y</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ge__><code>x.__ge__(<var>y</var>)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__ge__><code>x.<dfn>__ge__</dfn>(<var>y</var>)</code></a>
 <tr><th>
 <td>truth value in a boolean context
 <td><code class=pp>if x:</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__bool__><code>x.__bool__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__bool__><code>x.<dfn>__bool__</dfn>()</code></a>
 </table>

 <h2 id=pickle>Classes That Can Be Serialized</h2>
@@ -685,31 +685,31 @@ class FieldStorage:
 <tr><th>
 <td>a custom object copy
 <td><code class=pp>copy.copy(x)</code>
-<td><a href=http://docs.python.org/3.0/library/copy.html><code>x.__copy__()</code></a>
+<td><a href=http://docs.python.org/3.0/library/copy.html><code>x.<dfn>__copy__</dfn>()</code></a>
 <tr><th>
 <td>a custom object deepcopy
 <td><code class=pp>copy.deepcopy(x)</code>
-<td><a href=http://docs.python.org/3.0/library/copy.html><code>x.__deepcopy__()</code></a>
+<td><a href=http://docs.python.org/3.0/library/copy.html><code>x.<dfn>__deepcopy__</dfn>()</code></a>
 <tr><th>
 <td>to get an object&#8217;s state before pickling
 <td><code class=pp>pickle.dump(x, <var>file</var>)</code>
-<td><a href=http://docs.python.org/3.0/library/pickle.html#pickle-state><code>x.__getstate__()</code></a>
+<td><a href=http://docs.python.org/3.0/library/pickle.html#pickle-state><code>x.<dfn>__getstate__</dfn>()</code></a>
 <tr><th>
 <td>to serialize an object
 <td><code class=pp>pickle.dump(x, <var>file</var>)</code>
-<td><a href=http://docs.python.org/3.0/library/pickle.html#pickling-class-instances><code>x.__reduce__()</code></a>
+<td><a href=http://docs.python.org/3.0/library/pickle.html#pickling-class-instances><code>x.<dfn>__reduce__</dfn>()</code></a>
 <tr><th>
 <td>to serialize an object (new pickling protocol)
 <td><code class=pp>pickle.dump(x, <var>file</var>, <var>protocol_version</var>)</code>
-<td><a href=http://docs.python.org/3.0/library/pickle.html#pickling-class-instances><code>x.__reduce_ex__(<var>protocol_version</var>)</code></a>
+<td><a href=http://docs.python.org/3.0/library/pickle.html#pickling-class-instances><code>x.<dfn>__reduce_ex__</dfn>(<var>protocol_version</var>)</code></a>
 <tr><th>
 <td>control over how an object is created during unpickling
 <td><code class=pp>x = pickle.load(<var>file</var>)</code>
-<td><a href=http://docs.python.org/3.0/library/pickle.html#pickling-class-instances><code>x.__getnewargs__()</code></a>
+<td><a href=http://docs.python.org/3.0/library/pickle.html#pickling-class-instances><code>x.<dfn>__getnewargs__</dfn>()</code></a>
 <tr><th>
 <td>to restore an object&#8217;s state after unpickling
 <td><code class=pp>x = pickle.load(<var>file</var>)</code>
-<td><a href=http://docs.python.org/3.0/library/pickle.html#pickle-state><code>x.__setstate__()</code></a>
+<td><a href=http://docs.python.org/3.0/library/pickle.html#pickle-state><code>x.<dfn>__setstate__</dfn>()</code></a>
 </table>

 <h2 id=context-managers>Classes That Can Be Used in a <code>with</code> Block</h2>
@@ -726,11 +726,11 @@ class FieldStorage:
 <tr><th>
 <td>do something special when entering a <code>with</code> block
 <td><code class=pp>with x:</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__enter__><code>x.__enter__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__enter__><code>x.<dfn>__enter__</dfn>()</code></a>
 <tr><th>
 <td>do something special when leaving a <code>with</code> block
 <td><code class=pp>with x:</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__exit__><code>x.__exit__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__exit__><code>x.<dfn>__exit__</dfn>()</code></a>
 </table>

 <p>This is how the [FIXME-xref] <code>with <var>file</var></code> idiom works.
@@ -775,43 +775,43 @@ def __exit__(self, *args) -> None:
 <tr><th>
 <td>a class constructor
 <td><code class=pp>x = MyClass()</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__new__><code>x.__new__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__new__><code>x.<dfn>__new__</dfn>()</code></a>
 <tr><th>
 <td>a class destructor
 <td><code class=pp>del x</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__del__><code>x.__del__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__del__><code>x.<dfn>__del__</dfn>()</code></a>
 <tr><th>
 <td>only a specific set of attributes to be defined
 <td>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__slots__><code>x.__slots__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__slots__><code>x.<dfn>__slots__</dfn>()</code></a>
 <tr><th>
 <td>a custom hash value
 <td><code class=pp>hash(x)</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__hash__><code>x.__hash__()</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__hash__><code>x.<dfn>__hash__</dfn>()</code></a>
 <tr><th>
 <td>to get an attribute&#8217;s value
 <td><code class=pp>x.color</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__get__><code>type(x).__dict__['color'].__get__(x, type(x))</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__get__><code>type(x).<dfn>__dict__</dfn>['color'].__get__(x, type(x))</code></a>
 <tr><th>
 <td>to set an attribute&#8217;s value
 <td><code class=pp>x.color = 'PapayaWhip'</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__set__><code>type(x).__dict__['color'].__set__(x, 'PapayaWhip')</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__set__><code>type(x).<dfn>__dict__</dfn>['color'].__set__(x, 'PapayaWhip')</code></a>
 <tr><th>
 <td>to delete an attribute
 <td><code class=pp>del x.color</code>
-<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__delete__><code>type(x).__dict__['color'].__del__(x)</code></a>
+<td><a href=http://www.python.org/doc/3.0/reference/datamodel.html#object.__delete__><code>type(x).<dfn>__dict__</dfn>['color'].__del__(x)</code></a>
 <tr><th>
 <td>to control whether an object is an instance of your class
 <td><code class=pp>isinstance(x, MyClass)</code>
-<td><a href=http://www.python.org/dev/peps/pep-3119/#overloading-isinstance-and-issubclass><code>MyClass.__instancecheck__(x)</code></a>
+<td><a href=http://www.python.org/dev/peps/pep-3119/#overloading-isinstance-and-issubclass><code>MyClass.<dfn>__instancecheck__</dfn>(x)</code></a>
 <tr><th>
 <td>to control whether a class is a subclass of your class
 <td><code class=pp>issubclass(C, MyClass)</code>
-<td><a href=http://www.python.org/dev/peps/pep-3119/#overloading-isinstance-and-issubclass><code>MyClass.__subclasscheck__(C)</code></a>
+<td><a href=http://www.python.org/dev/peps/pep-3119/#overloading-isinstance-and-issubclass><code>MyClass.<dfn>__subclasscheck__</dfn>(C)</code></a>
 <tr><th>
 <td>to control whether a class is a subclass of your abstract base class
 <td><code class=pp>issubclass(C, MyABC)</code>
-<td><a href=http://docs.python.org/3.0/library/abc.html#abc.ABCMeta.__subclasshook__><code>MyABC.__subclasshook__(C)</code></a>
+<td><a href=http://docs.python.org/3.0/library/abc.html#abc.ABCMeta.__subclasshook__><code>MyABC.<dfn>__subclasshook__</dfn>(C)</code></a>
 </table>

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