| 1 | # From beebe@math.utah.edu Thu Aug 2 15:35:07 2001
|
|---|
| 2 | # Received: from mail.actcom.co.il [192.114.47.13]
|
|---|
| 3 | # by localhost with POP3 (fetchmail-5.7.4)
|
|---|
| 4 | # for arnold@localhost (single-drop); Thu, 02 Aug 2001 15:35:07 +0300 (IDT)
|
|---|
| 5 | # Received: by actcom.co.il (mbox arobbins)
|
|---|
| 6 | # (with Cubic Circle's cucipop (v1.31 1998/05/13) Thu Aug 2 16:02:36 2001)
|
|---|
| 7 | # X-From_: beebe@sunshine.math.utah.edu Thu Aug 2 15:41:13 2001
|
|---|
| 8 | # Received: from lmail.actcom.co.il by actcom.co.il with ESMTP
|
|---|
| 9 | # (8.9.1a/actcom-0.2) id PAA01349 for <arobbins@actcom.co.il>;
|
|---|
| 10 | # Thu, 2 Aug 2001 15:41:06 +0300 (EET DST)
|
|---|
| 11 | # (rfc931-sender: mail.actcom.co.il [192.114.47.13])
|
|---|
| 12 | # Received: from billohost.com (www.billohost.com [209.196.35.10])
|
|---|
| 13 | # by lmail.actcom.co.il (8.11.2/8.11.2) with ESMTP id f72Cf3I21032
|
|---|
| 14 | # for <arobbins@actcom.co.il>; Thu, 2 Aug 2001 15:41:05 +0300
|
|---|
| 15 | # Received: from fencepost.gnu.org (we-refuse-to-spy-on-our-users@fencepost.gnu.org [199.232.76.164])
|
|---|
| 16 | # by billohost.com (8.9.3/8.9.3) with ESMTP id IAA28585
|
|---|
| 17 | # for <arnold@skeeve.com>; Thu, 2 Aug 2001 08:34:38 -0400
|
|---|
| 18 | # Received: from sunshine.math.utah.edu ([128.110.198.2])
|
|---|
| 19 | # by fencepost.gnu.org with esmtp (Exim 3.22 #1 (Debian))
|
|---|
| 20 | # id 15SHjG-00036x-00
|
|---|
| 21 | # for <arnold@gnu.org>; Thu, 02 Aug 2001 08:37:30 -0400
|
|---|
| 22 | # Received: from suncore.math.utah.edu (IDENT:GsUbUdUYCtFLRE4HvnnvhN4JsjooYcfR@suncore0.math.utah.edu [128.110.198.5])
|
|---|
| 23 | # by sunshine.math.utah.edu (8.9.3/8.9.3) with ESMTP id GAA00190;
|
|---|
| 24 | # Thu, 2 Aug 2001 06:37:04 -0600 (MDT)
|
|---|
| 25 | # Received: (from beebe@localhost)
|
|---|
| 26 | # by suncore.math.utah.edu (8.9.3/8.9.3) id GAA20469;
|
|---|
| 27 | # Thu, 2 Aug 2001 06:37:03 -0600 (MDT)
|
|---|
| 28 | # Date: Thu, 2 Aug 2001 06:37:03 -0600 (MDT)
|
|---|
| 29 | # From: "Nelson H. F. Beebe" <beebe@math.utah.edu>
|
|---|
| 30 | # To: arnold@gnu.org
|
|---|
| 31 | # Cc: beebe@math.utah.edu
|
|---|
| 32 | # X-US-Mail: "Center for Scientific Computing, Department of Mathematics, 322
|
|---|
| 33 | # INSCC, University of Utah, 155 S 1400 E RM 233, Salt Lake City, UT
|
|---|
| 34 | # 84112-0090, USA"
|
|---|
| 35 | # X-Telephone: +1 801 581 5254
|
|---|
| 36 | # X-FAX: +1 801 585 1640, +1 801 581 4148
|
|---|
| 37 | # X-URL: http://www.math.utah.edu/~beebe
|
|---|
| 38 | # Subject: awk implementations: a bug, or new dark corner?
|
|---|
| 39 | # Message-ID: <CMM.0.92.0.996755823.beebe@suncore.math.utah.edu>
|
|---|
| 40 | # Status: RO
|
|---|
| 41 | #
|
|---|
| 42 | # Consider the following program:
|
|---|
| 43 | #
|
|---|
| 44 | # % cat bug.awk
|
|---|
| 45 | BEGIN {
|
|---|
| 46 | split("00/00/00",mdy,"/")
|
|---|
| 47 | if ((mdy[1] == 0) && (mdy[2] == 0) && (mdy[3] == 0))
|
|---|
| 48 | {
|
|---|
| 49 | print "OK: zero strings compare equal to number zero"
|
|---|
| 50 | exit(0)
|
|---|
| 51 | }
|
|---|
| 52 | else
|
|---|
| 53 | {
|
|---|
| 54 | print "ERROR: zero strings compare unequal to number zero"
|
|---|
| 55 | exit(1)
|
|---|
| 56 | }
|
|---|
| 57 | }
|
|---|
| 58 | #
|
|---|
| 59 | # Here are the awk implementation versions (on Sun Solaris 2.7):
|
|---|
| 60 | #
|
|---|
| 61 | # % awk -V
|
|---|
| 62 | # awk version 19990416
|
|---|
| 63 | #
|
|---|
| 64 | # % mawk -W version
|
|---|
| 65 | # mawk 1.3.3 Nov 1996, Copyright (C) Michael D. Brennan
|
|---|
| 66 | #
|
|---|
| 67 | # % nawk -V
|
|---|
| 68 | # awk version 20001115
|
|---|
| 69 | #
|
|---|
| 70 | # % gawk --version
|
|---|
| 71 | # GNU Awk 3.1.10
|
|---|
| 72 | # ...
|
|---|
| 73 | #
|
|---|
| 74 | # Here's what they say about the test program:
|
|---|
| 75 | #
|
|---|
| 76 | # foreach f (awk mawk nawk gawk gawk-*)
|
|---|
| 77 | # echo ======== $f
|
|---|
| 78 | # $f -f ~/bug.awk
|
|---|
| 79 | # end
|
|---|
| 80 | #
|
|---|
| 81 | # ======== awk
|
|---|
| 82 | # OK: zero strings compare equal to number zero
|
|---|
| 83 | # ======== mawk
|
|---|
| 84 | # OK: zero strings compare equal to number zero
|
|---|
| 85 | # ======== nawk
|
|---|
| 86 | # OK: zero strings compare equal to number zero
|
|---|
| 87 | # ======== gawk
|
|---|
| 88 | # ERROR: zero strings compare unequal to number zero
|
|---|
| 89 | # ======== gawk-3.0.0
|
|---|
| 90 | # OK: zero strings compare equal to number zero
|
|---|
| 91 | # ======== gawk-3.0.1
|
|---|
| 92 | # OK: zero strings compare equal to number zero
|
|---|
| 93 | # ======== gawk-3.0.3
|
|---|
| 94 | # OK: zero strings compare equal to number zero
|
|---|
| 95 | # ======== gawk-3.0.4
|
|---|
| 96 | # OK: zero strings compare equal to number zero
|
|---|
| 97 | # ======== gawk-3.0.5
|
|---|
| 98 | # OK: zero strings compare equal to number zero
|
|---|
| 99 | # ======== gawk-3.0.6
|
|---|
| 100 | # OK: zero strings compare equal to number zero
|
|---|
| 101 | # ======== gawk-3.0.60
|
|---|
| 102 | # OK: zero strings compare equal to number zero
|
|---|
| 103 | # ======== gawk-3.0.90
|
|---|
| 104 | # ERROR: zero strings compare unequal to number zero
|
|---|
| 105 | # ======== gawk-3.0.91
|
|---|
| 106 | # ERROR: zero strings compare unequal to number zero
|
|---|
| 107 | # ======== gawk-3.0.92
|
|---|
| 108 | # ERROR: zero strings compare unequal to number zero
|
|---|
| 109 | # ======== gawk-3.0.93
|
|---|
| 110 | # ERROR: zero strings compare unequal to number zero
|
|---|
| 111 | # ======== gawk-3.0.94
|
|---|
| 112 | # ERROR: zero strings compare unequal to number zero
|
|---|
| 113 | # ======== gawk-3.0.95
|
|---|
| 114 | # ERROR: zero strings compare unequal to number zero
|
|---|
| 115 | # ======== gawk-3.0.96
|
|---|
| 116 | # ERROR: zero strings compare unequal to number zero
|
|---|
| 117 | # ======== gawk-3.0.97
|
|---|
| 118 | # ERROR: zero strings compare unequal to number zero
|
|---|
| 119 | # ======== gawk-3.1.0
|
|---|
| 120 | # ERROR: zero strings compare unequal to number zero
|
|---|
| 121 | # ======== gawk-3.1.10
|
|---|
| 122 | # ERROR: zero strings compare unequal to number zero
|
|---|
| 123 | #
|
|---|
| 124 | # Identical results were obtained on Apple Rhapsody, Apple Darwin,
|
|---|
| 125 | # Compaq/DEC Alpha OSF/1, Intel x86 GNU/Linux, SGI IRIX 6.5, DEC Alpha
|
|---|
| 126 | # GNU/Linux, and Sun SPARC GNU/Linux, so it definitely is not a C
|
|---|
| 127 | # compiler problem.
|
|---|
| 128 | #
|
|---|
| 129 | # However, the gray awk book, p. 44, says:
|
|---|
| 130 | #
|
|---|
| 131 | # In a comparison expression like:
|
|---|
| 132 | # x == y
|
|---|
| 133 | # if both operands have a numeric type, the comparison is numeric;
|
|---|
| 134 | # otherwise, any numeric operand is converted to a string and the
|
|---|
| 135 | # comparison is made on the string values.
|
|---|
| 136 | #
|
|---|
| 137 | # and the new green gawk book, p. 95, says:
|
|---|
| 138 | #
|
|---|
| 139 | # When comparing operands of mixed types, numeric operands are
|
|---|
| 140 | # converted to strings using the value of `CONVFMT'
|
|---|
| 141 | #
|
|---|
| 142 | # This suggests that the OK response in bug.awk is wrong, and the ERROR
|
|---|
| 143 | # response is correct. Only recent gawk releases do the right thing,
|
|---|
| 144 | # and it is awk, mawk, and nawk that have a bug.
|
|---|
| 145 | #
|
|---|
| 146 | # If I change the test program from "00/00/00" to "0/0/0", all versions
|
|---|
| 147 | # tested produce the OK response.
|
|---|
| 148 | #
|
|---|
| 149 | # Comments?
|
|---|
| 150 | #
|
|---|
| 151 | # After reading the two book excerpts, I changed my code to read
|
|---|
| 152 | #
|
|---|
| 153 | # if (((0 + mdy[1]) == 0) && ((0 + mdy[2]) == 0) && ((0 + mdy[3]) == 0))
|
|---|
| 154 | #
|
|---|
| 155 | # and output from all implementations now agrees.
|
|---|
| 156 | #
|
|---|
| 157 | # -------------------------------------------------------------------------------
|
|---|
| 158 | # - Nelson H. F. Beebe Tel: +1 801 581 5254 -
|
|---|
| 159 | # - Center for Scientific Computing FAX: +1 801 585 1640, +1 801 581 4148 -
|
|---|
| 160 | # - University of Utah Internet e-mail: beebe@math.utah.edu -
|
|---|
| 161 | # - Department of Mathematics, 322 INSCC beebe@acm.org beebe@computer.org -
|
|---|
| 162 | # - 155 S 1400 E RM 233 beebe@ieee.org -
|
|---|
| 163 | # - Salt Lake City, UT 84112-0090, USA URL: http://www.math.utah.edu/~beebe -
|
|---|
| 164 | # -------------------------------------------------------------------------------
|
|---|
| 165 | #
|
|---|
