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<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta name="color-scheme" content="light dark"> <title>PEP 294 – Type Names in the types Module | peps.python.org</title> <link rel="shortcut icon" href="../_static/py.png"> <link rel="canonical" href="https://peps.python.org/pep-0294/"> <link rel="stylesheet" href="../_static/style.css" type="text/css"> <link rel="stylesheet" href="../_static/mq.css" type="text/css"> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" media="(prefers-color-scheme: light)" id="pyg-light"> <link rel="stylesheet" href="../_static/pygments_dark.css" type="text/css" media="(prefers-color-scheme: dark)" id="pyg-dark"> <link rel="alternate" type="application/rss+xml" title="Latest PEPs" href="https://peps.python.org/peps.rss"> <meta property="og:title" content='PEP 294 – Type Names in the types Module | peps.python.org'> <meta property="og:description" 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href="#svg-sun-half"></use></svg> <svg aria-hidden="true" class="colour-scheme-icon-when-dark"><use href="#svg-moon"></use></svg> <svg aria-hidden="true" class="colour-scheme-icon-when-light"><use href="#svg-sun"></use></svg> <span class="visually-hidden">Toggle light / dark / auto colour theme</span> </button> </header> <article> <section id="pep-content"> <h1 class="page-title">PEP 294 – Type Names in the types Module</h1> <dl class="rfc2822 field-list simple"> <dt class="field-odd">Author<span class="colon">:</span></dt> <dd class="field-odd">Oren Tirosh <oren at hishome.net></dd> <dt class="field-even">Status<span class="colon">:</span></dt> <dd class="field-even"><abbr title="Formally declined and will not be accepted">Rejected</abbr></dd> <dt class="field-odd">Type<span class="colon">:</span></dt> <dd class="field-odd"><abbr title="Normative PEP with a new feature for Python, implementation change for CPython or interoperability standard for the ecosystem">Standards Track</abbr></dd> <dt class="field-even">Created<span class="colon">:</span></dt> <dd class="field-even">19-Jun-2002</dd> <dt class="field-odd">Python-Version<span class="colon">:</span></dt> <dd class="field-odd">2.5</dd> <dt class="field-even">Post-History<span class="colon">:</span></dt> <dd class="field-even"><p></p></dd> </dl> <hr class="docutils" /> <section id="contents"> <details><summary>Table of Contents</summary><ul class="simple"> <li><a class="reference internal" href="#abstract">Abstract</a></li> <li><a class="reference internal" href="#pronouncement">Pronouncement</a></li> <li><a class="reference internal" href="#rationale">Rationale</a></li> <li><a class="reference internal" href="#specification">Specification</a></li> <li><a class="reference internal" href="#backward-compatibility">Backward compatibility</a></li> <li><a class="reference internal" href="#reference-implementation">Reference Implementation</a></li> <li><a class="reference internal" href="#copyright">Copyright</a></li> </ul> </details></section> <section id="abstract"> <h2><a class="toc-backref" href="#abstract" role="doc-backlink">Abstract</a></h2> <p>This PEP proposes that symbols matching the type name should be added to the types module for all basic Python types in the types module:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">types</span><span class="o">.</span><span class="n">IntegerType</span> <span class="o">-></span> <span class="n">types</span><span class="o">.</span><span class="n">int</span> <span class="n">types</span><span class="o">.</span><span class="n">FunctionType</span> <span class="o">-></span> <span class="n">types</span><span class="o">.</span><span class="n">function</span> <span class="n">types</span><span class="o">.</span><span class="n">TracebackType</span> <span class="o">-></span> <span class="n">types</span><span class="o">.</span><span class="n">traceback</span> <span class="o">...</span> </pre></div> </div> <p>The long capitalized names currently in the types module will be deprecated.</p> <p>With this change the types module can serve as a replacement for the new module. The new module shall be deprecated and listed in <a class="pep reference internal" href="../pep-0004/" title="PEP 4 – Deprecation of Standard Modules">PEP 4</a>.</p> </section> <section id="pronouncement"> <h2><a class="toc-backref" href="#pronouncement" role="doc-backlink">Pronouncement</a></h2> <p>A centralized repository of type names was a mistake. Neither the “types” nor “new” modules should be carried forward to Python 3.0.</p> <p>In the meantime, it does not make sense to make the proposed updates to the modules. This would cause disruption without any compensating benefit.</p> <p>Instead, the problem that some internal types (frames, functions, etc.) don’t live anywhere outside those modules may be addressed by either adding them to <code class="docutils literal notranslate"><span class="pre">__builtin__</span></code> or sys. This will provide a smoother transition to Python 3.0.</p> </section> <section id="rationale"> <h2><a class="toc-backref" href="#rationale" role="doc-backlink">Rationale</a></h2> <p>Using two sets of names for the same objects is redundant and confusing.</p> <p>In Python versions prior to 2.2 the symbols matching many type names were taken by the factory functions for those types. Now all basic types have been unified with their factory functions and therefore the type names are available to be consistently used to refer to the type object.</p> <p>Most types are accessible as either builtins or in the new module but some types such as traceback and generator are only accessible through the types module under names which do not match the type name. This PEP provides a uniform way to access all basic types under a single set of names.</p> </section> <section id="specification"> <h2><a class="toc-backref" href="#specification" role="doc-backlink">Specification</a></h2> <p>The types module shall pass the following test:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">types</span> <span class="k">for</span> <span class="n">t</span> <span class="ow">in</span> <span class="nb">vars</span><span class="p">(</span><span class="n">types</span><span class="p">)</span><span class="o">.</span><span class="n">values</span><span class="p">():</span> <span class="k">if</span> <span class="nb">type</span><span class="p">(</span><span class="n">t</span><span class="p">)</span> <span class="ow">is</span> <span class="nb">type</span><span class="p">:</span> <span class="k">assert</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">types</span><span class="p">,</span> <span class="n">t</span><span class="o">.</span><span class="vm">__name__</span><span class="p">)</span> <span class="ow">is</span> <span class="n">t</span> </pre></div> </div> <p>The types ‘class’, ‘instance method’ and ‘dict-proxy’ have already been renamed to the valid Python identifiers ‘classobj’, ‘instancemethod’ and ‘dictproxy’, making this possible.</p> </section> <section id="backward-compatibility"> <h2><a class="toc-backref" href="#backward-compatibility" role="doc-backlink">Backward compatibility</a></h2> <p>Because of their widespread use it is not planned to actually remove the long names from the types module in some future version. However, the long names should be changed in documentation and library sources to discourage their use in new code.</p> </section> <section id="reference-implementation"> <h2><a class="toc-backref" href="#reference-implementation" role="doc-backlink">Reference Implementation</a></h2> <p>A reference implementation is available in <a class="reference external" href="https://bugs.python.org/issue569328">issue #569328</a>.</p> </section> <section id="copyright"> <h2><a class="toc-backref" href="#copyright" role="doc-backlink">Copyright</a></h2> <p>This document has been placed in the public domain.</p> </section> </section> <hr class="docutils" /> <p>Source: <a class="reference external" href="https://github.com/python/peps/blob/main/peps/pep-0294.rst">https://github.com/python/peps/blob/main/peps/pep-0294.rst</a></p> <p>Last modified: <a class="reference external" href="https://github.com/python/peps/commits/main/peps/pep-0294.rst">2025-02-01 08:55:40 GMT</a></p> </article> <nav id="pep-sidebar"> <h2>Contents</h2> <ul> <li><a class="reference internal" href="#abstract">Abstract</a></li> <li><a class="reference internal" href="#pronouncement">Pronouncement</a></li> <li><a class="reference internal" href="#rationale">Rationale</a></li> <li><a class="reference internal" href="#specification">Specification</a></li> <li><a class="reference internal" href="#backward-compatibility">Backward compatibility</a></li> <li><a class="reference internal" href="#reference-implementation">Reference Implementation</a></li> <li><a class="reference internal" href="#copyright">Copyright</a></li> </ul> <br> <a id="source" href="https://github.com/python/peps/blob/main/peps/pep-0294.rst">Page Source (GitHub)</a> </nav> </section> <script src="../_static/colour_scheme.js"></script> <script src="../_static/wrap_tables.js"></script> <script src="../_static/sticky_banner.js"></script> </body> </html>