From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE, MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.4 Received: from minnie.tuhs.org (minnie.tuhs.org [IPv6:2600:3c01:e000:146::1]) by inbox.vuxu.org (Postfix) with ESMTP id B071E223C6 for ; Sun, 19 May 2024 16:03:40 +0200 (CEST) Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 3F9484334E; Mon, 20 May 2024 00:03:35 +1000 (AEST) Received: from mail-ot1-x334.google.com (mail-ot1-x334.google.com [IPv6:2607:f8b0:4864:20::334]) by minnie.tuhs.org (Postfix) with ESMTPS id EDEC34334B for ; Mon, 20 May 2024 00:03:30 +1000 (AEST) Received: by mail-ot1-x334.google.com with SMTP id 46e09a7af769-6f0f80b780fso1615864a34.2 for ; Sun, 19 May 2024 07:03:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dartmouth.edu; s=google1; t=1716127410; x=1716732210; darn=tuhs.org; h=to:subject:message-id:date:from:mime-version:from:to:cc:subject :date:message-id:reply-to; bh=X+d1lBCuEpYYacWVvylbEjW9A8SWPl5dzoReaUHEbjs=; b=PM56Lb+TBWF+Q4rXeLqwEeDk7D1EZ5alZa+vhSlsi5lSP7mjpuMvBREHg8HYyF4tNY aCljoDoT0yBt0rTq4JhmPY4o6BXXAMPrSqtUzsThaCVAE08y2Sia02yuzd+zBN8ZUcdz XtVxJn+SFz6699qA523rMuuwpVS+NqHnk6lSdEaMGKnopa6d2YjRUw6+KwS8y/PwyzFG LzI2K8Z81LntkIRDhjyYfGzK2RZqH0dX/7HSGUFXzjt/M/Fo3gmqWAQNcP4LcHutULEG qsWUWfljLRZkPBRt3nv/zgHjA6FiuNGwoxM/DHPMQ6nvDa26OdUNv6PDRWFrJ0H+2PPy nRhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1716127410; x=1716732210; h=to:subject:message-id:date:from:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=X+d1lBCuEpYYacWVvylbEjW9A8SWPl5dzoReaUHEbjs=; b=Ga1mViOjdDisf9ntCPn1U+Stw1T3YtcCk+lMmjQHSrWvVtXW8W8a4bZhOHsV6PqGWl DJE4iwlbUzl1BuS56exMBEBrz41Y4jLUQV5cgQDaRTCkgv6wfLe3s1Si2DlxedQ/ouII g/9MEXFZByhe3y6hmyE3j5zu2LF4n0ktL/NS6ybYB2pomb2yf2xt5mXaiqW8xacw/1yH OJN30p0FeZJbNalgqhtPuEwGzPpVrXhAIBb45vsvQYsWqrYvq3p89NhHKrOeQdHHPJfY X1w/rYx1YNbYDTSzeNRXJmKpffnkahPcVD6jNLvmgS2RiecUVNQC+yei/CRYAOX+qjDS 5GUg== X-Gm-Message-State: AOJu0YzbPQ3pz2+CwU6RGYQcoI6lq2erifsLerCp7dXifJ/GV1rbPnsm Q6LcBa03xyWQ2KvQWvbU+Y7JCkPMpoEK6rqJAXRJXnqDj1Z3ibEaRosRobU+0uecmjWcnpg5mqE whjVwQsfCIClF0AkuuAbvlQaipLKG6V8MWXX3/njaSbepbOl33xA= X-Google-Smtp-Source: AGHT+IGD/c8BEWZkkqHOC5FqP9IHSZ1WAQUceho3sa/aeeBLYuhRT+x4tb4wcdfInK+vj4L8HKrCKGDjPkjALHNnlnU= X-Received: by 2002:a05:6808:1916:b0:3c9:95e2:b080 with SMTP id 5614622812f47-3c997069950mr36614234b6e.25.1716127408350; Sun, 19 May 2024 07:03:28 -0700 (PDT) MIME-Version: 1.0 From: Douglas McIlroy Date: Sun, 19 May 2024 10:03:12 -0400 Message-ID: To: TUHS main list Content-Type: multipart/alternative; boundary="0000000000009084ee0618cf0cae" Message-ID-Hash: P5DZZXGHZ3QRLIYO6CIXQSAP55WFTH2O X-Message-ID-Hash: P5DZZXGHZ3QRLIYO6CIXQSAP55WFTH2O X-MailFrom: douglas.mcilroy@dartmouth.edu X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [TUHS] The 'usage: ...' message. (Was: On Bloat...) List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: --0000000000009084ee0618cf0cae Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable > was =E2=80=98usage: ...=E2=80=99 adopted from an earlier system? "Usage" was one of those lovely ideas, one exposure to which flips its status from unknown to eternal truth. I am sure my first exposure was on Unix, but I don't remember when. Perhaps because it radically departs from Ken's "?" in qed/ed, I have subconsciously attributed it to Dennis. The genius of "usage" and "?" is that they don't attempt to tell one what's wrong. Most diagnostics cite a rule or hidden limit that's been violated or describe the mistake (e.g. "missing semicolon") , sometimes raising more questions than they answer. Another non-descriptive style of error message that I admired was that of Berkeley Pascal's syntax diagnostics. When the LR parser could not proceed, it reported where, and automatically provided a sample token that would allow the parsing to progress. I found this uniform convention to be at least as informative as distinct hand-crafted messages, which almost by definition can't foresee every contingency. Alas, this elegant scheme seems not to have inspired imitators. Doug --0000000000009084ee0618cf0cae Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
> was =E2=80=98usage: ...=E2=80=99 ado= pted from an earlier system?

"Usa= ge" was one of those lovely ideas, one exposure to which flips its sta= tus from unknown to eternal truth. I am sure my first exposure was on Unix,= but I don't remember when. Perhaps because it radically departs from K= en's "?" in qed/ed, I have subconsciously attributed it to De= nnis.

The genius of "usage" and "?&= quot; is that they don't attempt to tell one what's wrong. Most dia= gnostics cite a rule or hidden limit that's been violated or describe t= he mistake (e.g. "missing semicolon") , sometimes raising more qu= estions than they answer.=C2=A0

Another non-descri= ptive style of error message that I admired was that of Berkeley Pascal'= ;s syntax diagnostics. When the LR parser could not proceed, it reported wh= ere, and automatically provided a sample token that would allow the parsing= to progress. I found this uniform convention to be at least as informative= as distinct hand-crafted messages, which almost by definition can't fo= resee every contingency. Alas, this elegant scheme seems not to have inspir= ed imitators.

Doug
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