Rationale:
It already is for scanning.
It is accepted for complexes already, but doesn't work.
It's analogous to %G and %E.
C accepts it too, and we try to be roughly compatible.
Fixes#7518.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/77580044
We forgot to include the width of "0x" when computing the crossover
from internal buffer to allocated buffer.
Also add a helper function to the test for formatting large zero-padded
test strings.
Fixes#6777.
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/50820043
This seems to be the best target to benchmark sync.Pool changes.
This is resend of cl/49910043 which was LGTMed by
TBR=bradfitz
R=golang-codereviews
CC=golang-codereviews
https://golang.org/cl/50140045
Space padding still has the same issue, I will send a separate patch for that
if this one gets accepted.
Fixes#6856.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/35660043
In an indexed verb such as %[3]d, if the index is out of range, don't
skip processing the rest of the verbs. The bug was that the bad
index set a bit for the whole format instead of just the verb.
Ok for 1.2 because this is a bug in a 1.2 feature.
Fixes#6434
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/13632058
Update #5000
Should reduce the flakiness a little. Malloc counting is important
to general testing but not to the build dashboard, which uses -short.
R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/12866047
If the padding is huge, we crashed by blowing the buffer. That's easy: make sure
we have a big enough buffer by allocating in problematic cases.
Zero padding floats was just wrong in general: the space would appear in the
middle.
Fixes#6044.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/12498043
The old code put the index before the period in the precision;
it should be after so it's always before the star, as documented.
A little trickier to do in one pass but compensated for by more
tests and catching a couple of other error cases.
R=rsc
CC=golang-dev
https://golang.org/cl/9751044
This text is added to doc.go:
Explicit argument indexes:
In Printf, Sprintf, and Fprintf, the default behavior is for each
formatting verb to format successive arguments passed in the call.
However, the notation [n] immediately before the verb indicates that the
nth one-indexed argument is to be formatted instead. The same notation
before a '*' for a width or precision selects the argument index holding
the value. After processing a bracketed expression [n], arguments n+1,
n+2, etc. will be processed unless otherwise directed.
For example,
fmt.Sprintf("%[2]d %[1]d\n", 11, 22)
will yield "22, 11", while
fmt.Sprintf("%[3]*[2].*[1]f", 12.0, 2, 6),
equivalent to
fmt.Sprintf("%6.2f", 12.0),
will yield " 12.00". Because an explicit index affects subsequent verbs,
this notation can be used to print the same values multiple times
by resetting the index for the first argument to be repeated:
fmt.Sprintf("%d %d %#[1]x %#x", 16, 17)
will yield "16 17 0x10 0x11".
The notation chosen differs from that in C, but I believe it's easier to read
and to remember (we're indexing the arguments), and compatibility with
C's printf was never a strong goal anyway.
While we're here, change the word "field" to "arg" or "argument" in the
code; it was being misused and was confusing.
R=rsc, bradfitz, rogpeppe, minux.ma, peter.armitage
CC=golang-dev
https://golang.org/cl/9680043
This CL also replaces similar loops in other stdlib
package tests with calls to AllocsPerRun.
Fixes#4461.
R=minux.ma, rsc
CC=golang-dev
https://golang.org/cl/7002055
Silly and small but easy to be consistent.
To make it worthwhile, I eliminated an allocation when using
%x on a byte slice.
Fixes#4149.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6574046
Before, pointers always appeared as 0x1234ABCD. This CL
keeps that as the default for %p and %v, but lets explicit
numeric verbs override the default.
Fixes#3936.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/6441152
The reordering speedup in CL 6245068 changed the semantics
of %#v by delaying the clearing of some flags. Restore the old
semantics and add a test.
Fixes#3706.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6302048
The check for Stringer etc. can only fire if the test is not a builtin, so avoid
the expensive check if we know there's no chance.
Also put in a fast path for pad, which saves a more modest amount.
benchmark old ns/op new ns/op delta
BenchmarkSprintfEmpty 148 152 +2.70%
BenchmarkSprintfString 585 497 -15.04%
BenchmarkSprintfInt 441 396 -10.20%
BenchmarkSprintfIntInt 718 603 -16.02%
BenchmarkSprintfPrefixedInt 676 621 -8.14%
BenchmarkSprintfFloat 1003 953 -4.99%
BenchmarkManyArgs 2945 2312 -21.49%
BenchmarkScanInts 1704152 1734441 +1.78%
BenchmarkScanRecursiveInt 1837397 1828920 -0.46%
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6245068
Unexports runtime.MemStats and rename MemStatsType to MemStats.
The new accessor requires passing a pointer to a user-allocated
MemStats structure.
Fixes#2572.
R=bradfitz, rsc, bradfitz, gustavo
CC=golang-dev, remy
https://golang.org/cl/5616072
We need to avoid allocating an extra word for the interface value
passing the floating-point value as an interface{}. It's easy.
Fixes#2722.
R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/5553044
On 32-bit machines, %g takes an extra malloc. I don't know why yet,
but this makes the test pass again, and enables it even for -short.
Fixes#2653.
R=golang-dev, bradfitz, r
CC=golang-dev
https://golang.org/cl/5542055
This is a slight change to fmt's semantics, but means that if you use
%d to print an integer with a Stringable value, it will print as an integer.
This came up because Time.Month() couldn't cleanly print as an integer
rather than a name. Using %d on Stringables is silly anyway, so there
should be no effect outside the fmt tests.
As a mild bonus, certain recursive failures of String methods
will also be avoided this way.
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/5453053
Got rid of all the magic mystery globals. Now
for %N, %T, and %S, the flags +,- and # set a sticky
debug, sym and export mode, only visible in the new fmt.c.
Default is error mode. Handle h and l flags consistently with
the least side effects, so we can now change
things without worrying about unrelated things
breaking.
fixes#2361
R=rsc
CC=golang-dev
https://golang.org/cl/5316043
Had been allowing it for use by fmt, but it is too hard to lock down.
Fix other packages not to depend on it.
R=r, r
CC=golang-dev
https://golang.org/cl/5266054
Interesting that Fprintf can do zero mallocs.
(Sprintf must allocate the returned string.)
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/4977049
