sprintf behavior or documentation bug #14773
Comments
From saint.snit@gmail.comThis is a bug report for perl from saint.snit@gmail.com, Hi, I've found a discrepancy between documentation and behavior. I'm not perldoc -f sprintf says, "When a space and a plus sign are given as printf '<%+ d>', 12; # prints "<+12>" However, the plus sign is printed even in the case of one number that printf '<%+ d>', 0; # prints "<+0>" instead of "<0>" or "< 0>" Is the documentation supposed to say "a plus sign is used to prefix a Thank you. Flags: Site configuration information for perl 5.20.2: Configured by Gentoo at Mon Apr 6 15:25:39 CDT 2015. Summary of my perl5 (revision 5 version 20 subversion 2) configuration: Locally applied patches: @INC for perl 5.20.2: Environment for perl 5.20.2: |
From @cowensSUSv3 says "+ The result of a signed conversion shall always begin with a This tells me that our documentation incorrectly used the word positive as Inline Patchdiff --git a/pod/perlfunc.pod b/pod/perlfunc.pod
index 650ad0e..a781158 100644
--- a/pod/perlfunc.pod
+++ b/pod/perlfunc.pod
@@ -7244,10 +7244,15 @@ For example:
printf '<%#B>', 12; # prints "<0B1100>"
When a space and a plus sign are given as the flags at once,
-a plus sign is used to prefix a positive number.
-
- printf '<%+ d>', 12; # prints "<+12>"
- printf '<% +d>', 12; # prints "<+12>"
+a plus sign is used to prefix a non-negative number in addition
+to the default prefixing of negative numbers.
+
+ printf '<%+ d>', -12; # prints "<-12>"
+ printf '<% +d>', -12; # prints "<-12>"
+ printf '<%+ d>', 0; # prints "<+0>"
+ printf '<% +d>', 0; # prints "<+0>"
+ printf '<%+ d>', 12; # prints "<+12>"
+ printf '<% +d>', 12; # prints "<+12>"
When the # flag and a precision are given in the %o conversion,
the precision is incremented if it's necessary for the leading "0".
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The RT System itself - Status changed from 'new' to 'open' |
From @tonycozOn Tue Jun 23 19:46:09 2015, saint.snit@gmail.com wrote:
I expect it's meant to ignore the space flag if the + flag is present, perl's sprintf() formatting mostly follows the C standard where applicable, which states: If the space and + flags both appear, the space flag is ignored. So it looks like: When a space and a plus sign are given as the flags at once, should be: When a space and a plus sign are given as the flags at once, Tony |
From saint.snit@gmail.com
This is a *much* clearer way to explain it than documenting the combined behavior anew. Even if the second explanation is fixed to say "nonnegative" rather than "positive," repeating the explanation at all only leaves the reader scrutinizing the two behavior descriptions to see what, if anything, is different. On the other hand, if you just say that adding a space has no effect on the +, the user will know immediately what to expect--and there's no chance of getting details wrong in the repeated explanation, because there isn't one. The benefits of modularization are just as applicable to documentation as to code. :-) |
From @jkeenanOn Thu Jun 25 06:08:14 2015, saint.snit@gmail.com wrote:
TonyC: Do you think we should go forward with this documentation change? Thank you very much. -- |
From @jkeenanOn Wed Dec 09 15:39:04 2015, jkeenan wrote:
TonyC: ping ^^ |
From @tonycozOn Fri Jan 22 19:29:02 2016, jkeenan wrote:
Here's an actualy patch. Tony |
From @tonycoz0001-perl-125471-clarify-sprintf-handling-of-and-space-fl.patchFrom 810a9637b4679691eb50c0b307b951411f23542b Mon Sep 17 00:00:00 2001
From: Tony Cook <tony@develop-help.com>
Date: Wed, 3 Feb 2016 11:35:28 +1100
Subject: [perl #125471] clarify sprintf() handling of + and space flags
---
pod/perlfunc.pod | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod
index 1dba05a..126bcb1 100644
--- a/pod/perlfunc.pod
+++ b/pod/perlfunc.pod
@@ -7167,7 +7167,11 @@ one or more of:
For example:
printf '<% d>', 12; # prints "< 12>"
+ printf '<% d>', 0; # prints "< 0>"
+ printf '<% d>', -12; # prints "<-12>"
printf '<%+d>', 12; # prints "<+12>"
+ printf '<%+d>', 0; # prints "<+0>"
+ printf '<%+d>', -12; # prints "<-12>"
printf '<%6s>', 12; # prints "< 12>"
printf '<%-6s>', 12; # prints "<12 >"
printf '<%06s>', 12; # prints "<000012>"
@@ -7178,7 +7182,7 @@ For example:
printf '<%#B>', 12; # prints "<0B1100>"
When a space and a plus sign are given as the flags at once,
-a plus sign is used to prefix a positive number.
+the space is ignored.
printf '<%+ d>', 12; # prints "<+12>"
printf '<% +d>', 12; # prints "<+12>"
--
2.1.4
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@jkeenan - Status changed from 'open' to 'resolved' |
Migrated from rt.perl.org#125471 (status was 'resolved')
Searchable as RT125471$
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