fmt: handle precision 0 format stings in standard way

fmt: handle precision 0 format stings in standard way The C-stdlib heritage of printf/fprintf/sprintf has two odd aspects for precisions of zero with integers. First, the zero can be specified in any of these ways, "%4.0d", "%.0d" and "%.d" which was not previously supported here. Secondly, the seemingly universal interpretation of precision for integers is that precision==0 and value==0 means print nothing at all. The code here now handles this for integers just as the code in big/int.c does the same for the Int type. New tests are added to fmt_test.go to verify these changes.

[r, 2011-07-21 06:45:15]

http://codereview.appspot.com/4717045/diff/2001/src/pkg/fmt/fmt_test.go File src/pkg/fmt/fmt_test.go (right): http://codereview.appspot.com/4717045/diff/2001/src/pkg/fmt/fmt_test.go#newco... src/pkg/fmt/fmt_test.go:185: {"%.d", 0, ""}, shouldn't there be non-zero test cases, the reason for the change?

[r, 2011-07-21 06:46:00]

apologies, never mind. i'm a CL behind. LGTM

[r, 2011-07-21 06:47:06]

*** Submitted as http://code.google.com/p/go/source/detail?r=8f4c6113ed2d *** fmt: handle precision 0 format stings in standard way The C-stdlib heritage of printf/fprintf/sprintf has two odd aspects for precisions of zero with integers. First, the zero can be specified in any of these ways, "%4.0d", "%.0d" and "%.d" which was not previously supported here. Secondly, the seemingly universal interpretation of precision for integers is that precision==0 and value==0 means print nothing at all. The code here now handles this for integers just as the code in big/int.c does the same for the Int type. New tests are added to fmt_test.go to verify these changes. R=r, r CC=golang-dev http://codereview.appspot.com/4717045 Committer: Rob Pike <r@golang.org>

[mtj1, 2011-07-21 06:51:01]

Great, thanks. One less dangling change in my tree! Michael T. Jones | Chief Technology Advocate | mtj@google.com | +1 650-335-5765 On Wed, Jul 20, 2011 at 11:47 PM, <r@golang.org> wrote: > *** Submitted as > http://code.google.com/p/go/**source/detail?r=8f4c6113ed2d<http://code.google... > > fmt: handle precision 0 format stings in standard way > > The C-stdlib heritage of printf/fprintf/sprintf has two odd > aspects for precisions of zero with integers. First, the zero > can be specified in any of these ways, "%4.0d", "%.0d" and > "%.d" which was not previously supported here. Secondly, the > seemingly universal interpretation of precision for integers > is that precision==0 and value==0 means print nothing at all. > The code here now handles this for integers just as the code > in big/int.c does the same for the Int type. New tests are > added to fmt_test.go to verify these changes. > > R=r, r > CC=golang-dev > > http://codereview.appspot.com/**4717045<http://codereview.appspot.com/4717045> > > Committer: Rob Pike <r@golang.org> > > > > http://codereview.appspot.com/**4717045/<http://codereview.appspot.com/4717045/> >