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|ID||Category||Severity||Type||Date Submitted||Last Update|
|0001130||[1003.1(2016/18)/Issue7+TC2] Shell and Utilities||Objection||Error||2017-03-21 17:07||2019-10-31 11:39|
|Reporter||Antonio Diaz||View Status||public|
|Priority||normal||Resolution||Accepted As Marked|
|Final Accepted Text||See Note: 0004105|
|Summary||0001130: Address 0 does not make sense for the c command|
The synopsis of the c command states that "Address 0 shall be valid for this command; it shall be interpreted as if address 1 were specified".
The RATIONALE of the ed utility states that "For consistency with the a and r commands and better user functionality, the i and c commands must also accept an address of 0, in which case 0i is treated as 1i and likewise for the c command".
But accepting 0 as a valid address for the c command does not make sense because the c command executes a d command, which does not admit an address of 0. With respect to addresses, the c command should be treated as the d command, not as the a, i or r commands, because a, i and r do not delete anything.
See discussion at http://lists.gnu.org/archive/html/bug-ed/2016-04/msg00009.html [^]
Remove from the synopsis of the c command and from the RATIONALE the requirement that the c command must accept address 0.
I did some digging into the history...
This requirement was not in the original POSIX.2-1992. It came into the standard via the .2b amendment. Unfortunately .2b does not give a clear explanation for the change. It specifies this change followed by a change to the Global command, and then says "The preceding two changes are the result of interpretation request PASC 1003.2-92 #119 submitted for IEEE Std 1003.2-1992." Interpretation #119 can be found in this online zip file:
but it is entirely about the Global command; there is no mention of the Change command. Presumably the update to the Change command arose when discussion of interpretation #119 digressed, but it is a shame that the .2b developers did not capture the reason for the change as rationale in .2b.
I wonder whether they were considering ranges - it makes sense for 0,2c to work the same as 1,2c - however I agree with Antonio that specifying 0c to be the same as 1c makes no sense. The only behaviour for 0c that makes sense to me would be for it to work like 0a, by analogy with s/^/string/ which inserts the string at the beginning of a line.
Since most ed implementations changed to support address 0 in order to conform to .2b, I suggest that rather than removing the requirement, we should make support for address 0 optional and say that if it is supported, the behaviour is unspecified.
Suggested change: On page 2682, line 87448, delete "Address 0 shall be valid for this command; it shall be interpreted as if address 1 were specified."
On page 2691, lines 87803-87805, change
edited on: 2018-09-06 16:43
Note that the resolution in Note: 0004105 includes rationale for the change in 0001131
|2017-03-21 17:07||Antonio Diaz||New Issue|
|2017-03-21 17:07||Antonio Diaz||Name||=> Antonio Diaz|
|2017-03-21 17:07||Antonio Diaz||Organization||=> GNU|
|2017-03-21 17:07||Antonio Diaz||Section||=> ed|
|2017-03-21 17:07||Antonio Diaz||Page Number||=> 0|
|2017-03-21 17:07||Antonio Diaz||Line Number||=> 0|
|2017-03-21 17:10||Antonio Diaz||Issue Monitored: Antonio Diaz|
|2017-03-21 18:26||salty-horse||Issue Monitored: salty-horse|
|2018-08-30 16:24||nick||Page Number||0 => 2682|
|2018-08-30 16:24||nick||Line Number||0 => 87448-87449|
|2018-08-30 16:24||nick||Interp Status||=> ---|
|2018-08-31 14:16||geoffclare||Note Added: 0004098|
|2018-09-06 16:33||geoffclare||Relationship added||related to 0001131|
|2018-09-06 16:36||nick||Note Added: 0004105|
|2018-09-06 16:37||nick||Final Accepted Text||=> See Bugnote:0004105|
|2018-09-06 16:37||nick||Status||New => Resolution Proposed|
|2018-09-06 16:37||nick||Resolution||Open => Accepted As Marked|
|2018-09-06 16:37||nick||Tag Attached: tc3-2008|
|2018-09-06 16:38||nick||Status||Resolution Proposed => Resolved|
|2018-09-06 16:43||nick||Note Added: 0004107|
|2018-09-06 16:43||nick||Note Edited: 0004107|
|2018-09-07 08:17||geoffclare||Final Accepted Text||See Bugnote:0004105 => See Note: 0004105|
|2019-10-31 11:39||geoffclare||Status||Resolved => Applied|
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