[1003.1(2016)/Issue7+TC2 0001198]: Comparison of numeric string values in awk
The following issue has a resolution that has been APPLIED. == http://austingroupbugs.net/view.php?id=1198 == Reported By:geoffclare Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1198 Category: Shell and Utilities Type: Error Severity: Objection Priority: normal Status: Applied Name: Geoff Clare Organization: The Open Group User Reference: Section:awk Page Number:2489 Line Number:80031 Interp Status: Approved Final Accepted Text:See http://austingroupbugs.net/view.php?id=1198#c4320. Resolution: Accepted As Marked Fixed in Version: == Date Submitted: 2018-08-07 10:40 UTC Last Modified: 2019-11-12 15:08 UTC == Summary:Comparison of numeric string values in awk == Issue History Date ModifiedUsername FieldChange == 2018-08-07 10:40 geoffclare New Issue 2018-08-07 10:40 geoffclare Name => Geoff Clare 2018-08-07 10:40 geoffclare Organization => The Open Group 2018-08-07 10:40 geoffclare Section => awk 2018-08-07 10:40 geoffclare Page Number => 2489 2018-08-07 10:40 geoffclare Line Number => 80031 2018-08-07 10:40 geoffclare Interp Status => --- 2019-03-14 15:45 Don Cragun Note Added: 0004320 2019-03-14 15:46 Don Cragun Final Accepted Text => See http://austingroupbugs.net/view.php?id=1198#c4320. 2019-03-14 15:46 Don Cragun Status New => Interpretation Required 2019-03-14 15:46 Don Cragun Resolution Open => Accepted As Marked 2019-03-14 15:46 Don Cragun Description Updated 2019-03-14 15:46 Don Cragun Tag Attached: tc3-2008 2019-03-14 15:55 Don Cragun Note Edited: 0004320 2019-03-16 06:32 agadminInterp Status--- => Proposed 2019-03-16 06:32 agadminNote Added: 0004325 2019-04-17 10:52 agadminInterp StatusProposed => Approved 2019-04-17 10:52 agadminNote Added: 0004369 2019-11-12 15:08 geoffclare Status Interpretation Required => Applied ==
[1003.1(2016)/Issue7+TC2 0001198]: Comparison of numeric string values in awk
The following issue has been UPDATED. == http://austingroupbugs.net/view.php?id=1198 == Reported By:geoffclare Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1198 Category: Shell and Utilities Type: Error Severity: Objection Priority: normal Status: Interpretation Required Name: Geoff Clare Organization: The Open Group User Reference: Section:awk Page Number:2489 Line Number:80031 Interp Status: Approved Final Accepted Text:See http://austingroupbugs.net/view.php?id=1198#c4320. == Date Submitted: 2018-08-07 10:40 UTC Last Modified: 2019-04-17 10:52 UTC == Summary:Comparison of numeric string values in awk == -- (0004369) agadmin (administrator) - 2019-04-17 10:52 http://austingroupbugs.net/view.php?id=1198#c4369 -- Interpretation approved: 17 April 2019 Issue History Date ModifiedUsername FieldChange == 2018-08-07 10:40 geoffclare New Issue 2018-08-07 10:40 geoffclare Name => Geoff Clare 2018-08-07 10:40 geoffclare Organization => The Open Group 2018-08-07 10:40 geoffclare Section => awk 2018-08-07 10:40 geoffclare Page Number => 2489 2018-08-07 10:40 geoffclare Line Number => 80031 2018-08-07 10:40 geoffclare Interp Status => --- 2019-03-14 15:45 Don Cragun Note Added: 0004320 2019-03-14 15:46 Don Cragun Final Accepted Text => See http://austingroupbugs.net/view.php?id=1198#c4320. 2019-03-14 15:46 Don Cragun Status New => Interpretation Required 2019-03-14 15:46 Don Cragun Resolution Open => Accepted As Marked 2019-03-14 15:46 Don Cragun Description Updated 2019-03-14 15:46 Don Cragun Tag Attached: tc3-2008 2019-03-14 15:55 Don Cragun Note Edited: 0004320 2019-03-16 06:32 agadminInterp Status--- => Proposed 2019-03-16 06:32 agadminNote Added: 0004325 2019-04-17 10:52 agadminInterp StatusProposed => Approved 2019-04-17 10:52 agadminNote Added: 0004369 ==
[1003.1(2016)/Issue7+TC2 0001198]: Comparison of numeric string values in awk
The following issue has been UPDATED. == http://austingroupbugs.net/view.php?id=1198 == Reported By:geoffclare Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1198 Category: Shell and Utilities Type: Error Severity: Objection Priority: normal Status: Interpretation Required Name: Geoff Clare Organization: The Open Group User Reference: Section:awk Page Number:2489 Line Number:80031 Interp Status: Proposed Final Accepted Text:See http://austingroupbugs.net/view.php?id=1198#c4320. == Date Submitted: 2018-08-07 10:40 UTC Last Modified: 2019-03-16 06:32 UTC == Summary:Comparison of numeric string values in awk == -- (0004325) agadmin (administrator) - 2019-03-16 06:32 http://austingroupbugs.net/view.php?id=1198#c4325 -- Interpretation Proposed: 16 March 2019 Issue History Date ModifiedUsername FieldChange == 2018-08-07 10:40 geoffclare New Issue 2018-08-07 10:40 geoffclare Name => Geoff Clare 2018-08-07 10:40 geoffclare Organization => The Open Group 2018-08-07 10:40 geoffclare Section => awk 2018-08-07 10:40 geoffclare Page Number => 2489 2018-08-07 10:40 geoffclare Line Number => 80031 2018-08-07 10:40 geoffclare Interp Status => --- 2019-03-14 15:45 Don Cragun Note Added: 0004320 2019-03-14 15:46 Don Cragun Final Accepted Text => See http://austingroupbugs.net/view.php?id=1198#c4320. 2019-03-14 15:46 Don Cragun Status New => Interpretation Required 2019-03-14 15:46 Don Cragun Resolution Open => Accepted As Marked 2019-03-14 15:46 Don Cragun Description Updated 2019-03-14 15:46 Don Cragun Tag Attached: tc3-2008 2019-03-14 15:55 Don Cragun Note Edited: 0004320 2019-03-16 06:32 agadminInterp Status--- => Proposed 2019-03-16 06:32 agadminNote Added: 0004325 ==
[1003.1(2016)/Issue7+TC2 0001198]: Comparison of numeric string values in awk
The following issue NEEDS AN INTERPRETATION. == http://austingroupbugs.net/view.php?id=1198 == Reported By:geoffclare Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1198 Category: Shell and Utilities Type: Error Severity: Objection Priority: normal Status: Interpretation Required Name: Geoff Clare Organization: The Open Group User Reference: Section:awk Page Number:2489 Line Number:80031 Interp Status: --- Final Accepted Text:See http://austingroupbugs.net/view.php?id=1198#c4320. == Date Submitted: 2018-08-07 10:40 UTC Last Modified: 2019-03-14 15:46 UTC == Summary:Comparison of numeric string values in awk == Issue History Date ModifiedUsername FieldChange == 2018-08-07 10:40 geoffclare New Issue 2018-08-07 10:40 geoffclare Name => Geoff Clare 2018-08-07 10:40 geoffclare Organization => The Open Group 2018-08-07 10:40 geoffclare Section => awk 2018-08-07 10:40 geoffclare Page Number => 2489 2018-08-07 10:40 geoffclare Line Number => 80031 2018-08-07 10:40 geoffclare Interp Status => --- 2019-03-14 15:45 Don Cragun Note Added: 0004320 2019-03-14 15:46 Don Cragun Final Accepted Text => See http://austingroupbugs.net/view.php?id=1198#c4320. 2019-03-14 15:46 Don Cragun Status New => Interpretation Required 2019-03-14 15:46 Don Cragun Resolution Open => Accepted As Marked 2019-03-14 15:46 Don Cragun Description Updated ==
[1003.1(2016)/Issue7+TC2 0001198]: Comparison of numeric string values in awk
A NOTE has been added to this issue. == http://austingroupbugs.net/view.php?id=1198 == Reported By:geoffclare Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1198 Category: Shell and Utilities Type: Error Severity: Objection Priority: normal Status: New Name: Geoff Clare Organization: The Open Group User Reference: Section:awk Page Number:2489 Line Number:80031 Interp Status: --- Final Accepted Text: == Date Submitted: 2018-08-07 10:40 UTC Last Modified: 2019-03-14 15:45 UTC == Summary:Comparison of numeric string values in awk == -- (0004320) Don Cragun (manager) - 2019-03-14 15:45 http://austingroupbugs.net/view.php?id=1198#c4320 -- Interpretation response The standard states that numeric strings are compared as strings, and conforming implementations must conform to this. However, concerns have been raised about this which are being referred to the sponsor. On the question of whether an uninitialized field has a string value, the standard is unclear on this issue, and no conformance distinction can be made between alternative implementations based on this. This is being referred to the sponsor. Rationale: - This is not the intended behavior. Notes to the Editor (not part of this interpretation): --- Make the following changes: On page 2485 line 79876 section awk change: $expr | Field reference |String | N/A to: $expr | Field reference | Uninitialized or string | N/A On page 2489 line 80031-80033 section awk change: Comparisons (with the '<', "<=", "!=", "==", '>', and ">=" operators) shall be made numerically if both operands are numeric, if one is numeric and the other has a string value that is a numeric string, or if one is numeric and the other has the uninitialized value. to: Comparisons (with the '<', "<=", "!=", "==", '>', and ">=" operators) shall be made numerically: . if both operands are numeric, . if one is numeric and the other has a string value that is a numeric string, . if both have string values that are numeric strings, or . if one is numeric and the other has the uninitialized value. Issue History Date ModifiedUsername FieldChange == 2018-08-07 10:40 geoffclare New Issue 2018-08-07 10:40 geoffclare Name => Geoff Clare 2018-08-07 10:40 geoffclare Organization => The Open Group 2018-08-07 10:40 geoffclare Section => awk 2018-08-07 10:40 geoffclare Page Number => 2489 2018-08-07 10:40 geoffclare Line Number => 80031 2018-08-07 10:40 geoffclare Interp Status => --- 2019-03-14 15:45 Don Cragun Note Added: 0004320 ==
Re: [1003.1(2016)/Issue7+TC2 0001198]: Comparison of numeric string values in awk
Date:Wed, 8 Aug 2018 14:42:38 +0100 From:Stephane Chazelas Message-ID: <20180808134238.ga16...@chaz.gmail.com> | By the way, you can also convert a string to numeric with: | if (x+0 < y+0) Yes, thanks, I knew how to convert, just not whether it was supposed to be necessary or not. In the actual script, the variables should be numeric, the real bug is that one of them is defined to be a string. | BSDs at the time. I don't know if they're still affected, you | may want to check on NetBSD. NetBSD uses nawk, which is still affected it seems. I will see if that can get fixed. kre ps: I do not believe that "print x < y" is valid awk, because of the ambiguity with "print x > y" I assume, and that it would be bizarre to allow < and not > in that context. To use the relational ops, parentheses are needed, as in "print (x < y)".
Re: [1003.1(2016)/Issue7+TC2 0001198]: Comparison of numeric string values in awk
2018-08-08 16:26:25 +0700, Robert Elz:
> Date:Wed, 8 Aug 2018 09:28:57 +0100
> From:Geoff Clare
> Message-ID: <20180808082857.GA6879@lt2.masqnet>
>
> | No it can't.
>
> Thanks, that's sort of what we thought, but the script exists, and
> rather than blindly just "fix" it we wanted to be sure.
>
> It "works" as it is, I believe, puerly because the "numbers" it is
> comparing all are the same order of magnitude (have the same
> number of digits) so a string comparison gives the same answer
> as a numeric one (which is what it should be doing) would.
[...]
By the way, you can also convert a string to numeric with:
if (x+0 < y+0)
It also covers the case where the content of x is from one of
those sources that can be considered as numeric strings (like
-v, $1...) but are not considered as such because they have
trailing garbage.
For instance:
awk -v 'x=10$' -v 'y=2$' 'BEGIN{print x < y}'
would print 1.
awk -v 'x=10$' -v 'y=2$' 'BEGIN{print 0+x < 0+y}'
would print 0 as x and y have been converted to 10 and 2
numbers.
BTW, some people use:
awk -v 'x=10$' -v 'y=2$' 'BEGIN{print +x < +y}'
But that's not portable. In historical implementations, the
unary + is a no-op and doesn't force conversion to number.
That's a conformance bug. I did report it to bwk, but not to
BSDs at the time. I don't know if they're still affected, you
may want to check on NetBSD.
It was discussed here a few years ago:
http://thread.gmane.org/gmane.comp.standards.posix.austin.general/11391
--
Stephane
Re: [1003.1(2016)/Issue7+TC2 0001198]: Comparison of numeric string values in awk
Robert Elz wrote, on 08 Aug 2018: > > This is not really about issue 1198, but a question raised by > thinking about issue 1198 ... > > The question is, when an awk script does (not on the command > line, but in the script) > > x="10" > > can the value of x ever be considered a numeric string (in the > awk definition technical sense) ? No it can't. The standard has a list of 8 sources of string values that are eligible for it to be considered a numeric string, and variable assignment from a string literal does not qualify as any of them. -- Geoff Clare The Open Group, Apex Plaza, Forbury Road, Reading, RG1 1AX, England
Re: [1003.1(2016)/Issue7+TC2 0001198]: Comparison of numeric string values in awk
This is not really about issue 1198, but a question raised by
thinking about issue 1198 ...
The question is, when an awk script does (not on the command
line, but in the script)
x="10"
can the value of x ever be considered a numeric string (in the
awk definition technical sense) ?
This arose because a real-life awk script is written (for whatever
reason) starting something like
awk "
BEGIN {
x = \"$x\" ;
}
/* and all the rest */
"
and 'x' is clearly intended to be treated numerically.I suspect that
the embedded quotes are to allow for the possibility that the shell
variable x (the $x) is not set (or null), since
x= ;
is not valid awk syntax... I would have written it (in the BEGIN block) ...
x = ${x:-0};
or
${x:+x=${x};}
or just made it a cmd line var assignment (I suspect that was not done as
there are actually quite a lot of them, not just this one) but I did not write
it.
kre
[1003.1(2016)/Issue7+TC2 0001198]: Comparison of numeric string values in awk
The following issue has been SUBMITTED. == http://austingroupbugs.net/view.php?id=1198 == Reported By:geoffclare Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1198 Category: Shell and Utilities Type: Error Severity: Objection Priority: normal Status: New Name: Geoff Clare Organization: The Open Group User Reference: Section:awk Page Number:2489 Line Number:80031 Interp Status: --- Final Accepted Text: == Date Submitted: 2018-08-07 10:40 UTC Last Modified: 2018-08-07 10:40 UTC == Summary:Comparison of numeric string values in awk Description: [The following was reported to The Open Group help desk.] The "Expressions In Awk" section of the standard says: --- Comparisons (with the '<', "<=", "!=", "==", '>', and ">=" operators) shall be made numerically if both operands are numeric, if one is numeric and the other has a string value that is a numeric string, or if one is numeric and the other has the uninitialized value. Otherwise, operands shall be converted to strings as required and a string comparison shall be made --- That's means that when a comparison involves 2 numeric strings it is a string comparison but of course in reality in all awks it is treated as a numeric comparison so that, for example, this: echo '5.0 10.0' | awk '$1 < $2' evaluates to true rather than false. There are some other confusing/misleading statements (at best) in the standard around the type of input fields and their value that could be written far more clearly - see https://groups.google.com/d/msg/comp.lang.awk/qYhgpz08pN8/9wbMr9XKCQAJ and https://stackoverflow.com/q/51632945/1745001 for discussions that have taken place recently on different forums around this area. [The comp.lang.awk discussion also talks about uninitialized fields behaving differently than uninitialized variables in some awks when compared to 0, but I think the standard is clear and intends what it says, so this is simply non-conforming behaviour in those awks. I think it is certainly undesirable for uninitialized fields to behave differently than uninitialized variables.] [The stackoverflow.com discussion is also about uninitialized fields but includes an answer which points out that the expressions table has this entry: Syntax | Name | Type of Result | Associativity $expr | Field reference |String | N/A which conflicts with the descriptive text in that it implies field variables always yield string values when used in an expression.] Desired Action: On page 2489 line 80031 section awk change:... shall be made numerically if both operands are numeric, ...to:... shall be made numerically if both operands are numeric, if both have string values that are numeric strings, ... On page 2485 line 79876 section awk change:$expr | Field reference |String | N/Ato:$expr | Field reference | Uninitialized or string | N/A == Issue History Date ModifiedUsername FieldChange == 2018-08-07 10:40 geoffclare New Issue 2018-08-07 10:40 geoffclare Name => Geoff Clare 2018-08-07 10:40 geoffclare Organization => The Open Group 2018-08-07 10:40 geoffclare Section => awk 2018-08-07 10:40 geoffclare Page Number => 2489 2018-08-07 10:40 geoffclare Line Number => 80031 2018-08-07 10:40 geoffclare Interp Status => --- ==
