Move the decision if zero padding is allowed to doPrintf
where the other formatting decisions are made.
Removes some dead code for negative f.wid that was never used
due to f.wid always being positive and f.minus deciding if left
or right padding should be used.
New padding code writes directly into the buffer and is as fast
as the old version but avoids the cost of needing package init.
name old time/op new time/op delta
SprintfPadding-2 246ns ± 5% 245ns ± 4% ~ (p=0.345 n=50+47)
Change-Id: I7dfddbac8e328f4ef0cdee8fafc0d06c784b2711
Reviewed-on: https://go-review.googlesource.com/19957
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
The construction
fmt.Printf("%*d", n, 4)
reads the argument n as a width specifier to use when printing 4.
Until now, only strict int type was accepted here and it couldn't
be fixed because the fix, using reflection, broke escape analysis
and added an extra allocation in every Printf call, even those that
do not use this feature.
The compiler has been fixed, although I am not sure when exactly,
so let's fix Printf and then write
Fixes#10732.
Change-Id: I79cf0c4fadd876265aa39d3cb62867247b36ab65
Reviewed-on: https://go-review.googlesource.com/14491
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Negative width arguments now left align the way a minus-width in the
format string aligns. The minus in the format string overrides the sign
of the argument as in C.
Precision behavior is modified to include an error if the argument is
negative. This differs from a negative precision in a format string
which just terminates the format.
Additional checks for large magnitude widths and precisions are added to
make the runtime behavior (failure, but with different error messages),
more consistent between format string specified width/precision and
argument specified width/precision.
Fixes#11376
Change-Id: I8c7ed21088e9c18128a45d4c487c5ab9fafd13ef
Reviewed-on: https://go-review.googlesource.com/11405
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Rob Pike <r@golang.org>
The old one was inferior.
Fixes#10695.
Change-Id: Ia7fb88c9ceb1b10197b77a54f729865385288d98
Reviewed-on: https://go-review.googlesource.com/9709
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
When a reflect.Value is passed to Printf (etc.), fmt called the
String method, which does not disclose its contents. To get the
contents, one could call Value.Interface(), but that is illegal
if the Value is not exported or otherwise forbidden.
This CL improves the situation with a trivial change to the
fmt package: when we see a reflect.Value as an argument,
we treat it exactly as we treat a reflect.Value we make inside
the package. This means that we always print the
contents of the Value as if _that_ was the argument to Printf.
This is arguably a breaking change but I think it is a genuine
improvement and no greater a break than many other tweaks
we have made to formatted output from this package.
Fixes#8965.
Change-Id: Ifc2a4ce3c1134ad5160e101d2196c22f1542faab
Reviewed-on: https://go-review.googlesource.com/8731
Reviewed-by: roger peppe <rogpeppe@gmail.com>
Reviewed-by: Russ Cox <rsc@golang.org>
It was inconsistent.
Also test these better.
Also document the default format for types.
This wasn't written down.
Fixes#8470.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/154870043
Apply a similar transformation to %+v that we did to %#v, making it
a top-level setting separate from the + flag itself. This fixes the
appearance of flags in Formatters and cleans up the code too,
probably making it a little faster.
Fixes#8835.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/154820043
The %#v verb is special: it says all values below need to print as %#v.
However, for some situations the # flag has other meanings and this
causes some issues, particularly in how Formatters work. Since %#v
dominates all formatting, translate it into actual state of the formatter
and decouple it from the # flag itself within the calculations (although
it must be restored when methods are doing the work.)
The result is cleaner code and correct handling of # for Formatters.
TODO: Apply the same thinking to the + flag in a followup CL.
Also, the wasString return value in handleMethods is always false,
so eliminate it.
Update #8835
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/146650043
This thing should never be called, but before
151960044 it was being called, incorrectly.
This is now just a precaution but let's pretend it
Fixes#8843
even though that was fixed by 151960044.
The test case was already there and ran, another mystery.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/151970043
