Newsgroups: php.internals Path: news.php.net Xref: news.php.net php.internals:114218 Return-Path: Delivered-To: mailing list internals@lists.php.net Received: (qmail 49771 invoked from network); 27 Apr 2021 22:43:53 -0000 Received: from unknown (HELO php-smtp4.php.net) (45.112.84.5) by pb1.pair.com with SMTP; 27 Apr 2021 22:43:53 -0000 Received: from php-smtp4.php.net (localhost [127.0.0.1]) by php-smtp4.php.net (Postfix) with ESMTP id 961761804DF for ; Tue, 27 Apr 2021 15:48:16 -0700 (PDT) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on php-smtp4.php.net X-Spam-Level: X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,HTML_MESSAGE, RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.2 X-Spam-Virus: No X-Envelope-From: Received: from mail-oi1-f175.google.com (mail-oi1-f175.google.com [209.85.167.175]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by php-smtp4.php.net (Postfix) with ESMTPS for ; Tue, 27 Apr 2021 15:48:16 -0700 (PDT) Received: by mail-oi1-f175.google.com with SMTP id k25so61242719oic.4 for ; Tue, 27 Apr 2021 15:48:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dTyXgHDFsXRv9YLhg+8f9o9KOTXvZv0d8xLlCPur9x8=; b=hoPR2mvlFt1rvnu5Bg8GcbsuCbopozpD4dGTEa8kXSr1z79sMrZ5ddqJuxuEJkkYab xjrvnEBcYuEU1SdKXWfEbv7Dv01wG/3fmmU+Kq/MtsisJuSl0SxwbRLX4hVGdLitjmc0 e2zS53UxJM8f9BdCpQ4OBeaB05rZWuNSOPNQofSQOlcLG/DYG37L/6/V0m0CJbLzI145 4A2BB+lFux7+apyLPxq3bLWHen0HxI+ZrBgq9SZoAdhx67Eh2JYov9wGYYGRcyobMcBn E8aLN5VQ7w/WNPlX4/ARPf9wfHAqWMDEQ6ZO9woz+f1NFuQ+1qaqYv+3IFEGyMHBYc2b An7g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=dTyXgHDFsXRv9YLhg+8f9o9KOTXvZv0d8xLlCPur9x8=; b=EEAQAl06on+uMiwxpmuzSKVeTW7wPv8R4KgCy23iZxb4Fy7rpidOPsYe4fyQoayGFk pCYkJ7ONilh0WJGcM2+jucYGmLqUB0Ojy/V7I+PzMIg+5rbsBzMCr6owaFfq8/1VL5aS 8/4FTDhvbYTbYjS81grJdI+np8ep4SPyll1Nw+xXav0G+QSD3+AnIwTMubqLewiVl5hQ gC5hFbqrT8D5BqVBUf7Py5Y7cNdWeQ2xRMH0Elo6to5FvQi67ToJHm27Gz7U6ZNPSOHj jYNhfusSDpc3gEVGPAjEQTpxSi4TiTW7rkwiw/6We3krIh3uU9oo2WvcI+DkXf/N7qfj utlA== X-Gm-Message-State: AOAM5305liqJTzS9M5NWU3ReN0aSyMI2EjAIXFdLWx+AunzJPXjfGk8H s6ktehsOOMTKCzZb1VG329LDwzS8LChk8k2N3F1cff8frij7ILf9 X-Google-Smtp-Source: ABdhPJwIiZ4CE8eUxJiuwdW4ztjG8whqVRG0hFw6e4u4sjVFWgpieffsRSc5uRL5W8jFdMfG03w6qhcSGqOnARkTNDY= X-Received: by 2002:aca:c395:: with SMTP id t143mr425179oif.152.1619563695434; Tue, 27 Apr 2021 15:48:15 -0700 (PDT) MIME-Version: 1.0 References: <5b9f1500-615a-48f1-815f-1d48b327ef90@processus.org> <179049b1475.11134368b213512.254739612773841999@void.tn> <722ed544-69e3-3be4-f828-185914617228@processus.org> <51fffd88-03c7-463d-a6d7-94c086cb5893@www.fastmail.com> In-Reply-To: <51fffd88-03c7-463d-a6d7-94c086cb5893@www.fastmail.com> Date: Tue, 27 Apr 2021 23:48:04 +0100 Message-ID: To: Larry Garfield Cc: php internals Content-Type: multipart/alternative; boundary="000000000000c1f03305c0fc0e00" Subject: Re: [PHP-DEV] [RFC][Draft] Sealed Classes From: davidgebler@gmail.com (David Gebler) --000000000000c1f03305c0fc0e00 Content-Type: text/plain; charset="UTF-8" On Tue, Apr 27, 2021 at 11:23 PM Larry Garfield wrote: The two options to prevent such errors are: > > 1. Sealed classes. > 2. Extend Enums into ADTs. > Unless I've misunderstood your example, there is a third option which quite possibly prevents the error in a nicer, easier to reason about, more flexible pattern. class Perhaps extends Maybe implements OperatesOnTheValueInterface { ... } --000000000000c1f03305c0fc0e00--