https://nalar.dev/tags/protocols/ Recent content in Protocols on Nalar Hugo en-us Tue, 01 Sep 2026 00:00:00 +0700 https://nalar.dev/python-protocols-and-structural-subtyping/ Tue, 01 Sep 2026 00:00:00 +0700 https://nalar.dev/python-protocols-and-structural-subtyping/ <p>Python code often depends on behavior rather than a specific class hierarchy. A function may only need an object with a <code>send()</code> method, a <code>read()</code> method, or a pair of repository operations.</p> <p><code>typing.Protocol</code> lets type checkers describe those behavioral requirements directly. A class satisfies a protocol by having compatible members; it does not need to inherit from the protocol.</p> <p>This is structural subtyping: &ldquo;if it has the required shape, it can be used here.&rdquo;</p>