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
Phrases like "returns whether or not the image is opaque" could be
describing what the function does (it always returns, regardless of
the opacity) or what it returns (a boolean indicating the opacity).
Even when the "or not" is missing, the phrasing is bizarre.
Go with "reports whether", which is still clunky but at least makes
it clear we're talking about the return value.
These were edited by hand. A few were cleaned up in other ways.
R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/11699043
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
The String method is called whenever the printing operation wants a string,
not just for %s and %v.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/8638043
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
%g down to two mallocs from four. Also a mild speedup.
fmt_test.BenchmarkSprintfFloat 3016 2703 -10.38%
Fixes#2557.
R=rsc
CC=golang-dev
https://golang.org/cl/5491054
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
Handling os.Error is no different than handling fmt.Stringer
here, so the code is redundant now, but it will be necessary
once error goes in.
Adding it now will make gofix fix it.
R=r
CC=golang-dev
https://golang.org/cl/5331045
Store the reflect.Value in the internal print state. Code is simpler, cleaner,
and a little faster - back to what it was before the change.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/5299046
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
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
https://golang.org/cl/4717045
The public godoc looked confused. I imagine these were
written before current conventions were established.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4662060
This is a core API change.
1) gofix misc src
2) Manual adjustments to the following files under src/pkg:
gob/decode.go
rpc/client.go
os/error.go
io/io.go
bufio/bufio.go
http/request.go
websocket/client.go
as well as:
src/cmd/gofix/testdata/*.go.in (reverted)
test/fixedbugs/bug243.go
3) Implemented gofix patch (oserrorstring.go) and test case (oserrorstring_test.go)
Compiles and runs all tests.
R=r, rsc, gri
CC=golang-dev
https://golang.org/cl/4607052
This change causes Print et al. to catch panics generated by
calls to String, GoString, and Format. The panic is formatted
into the output stream as an error, but the program continues.
As a special case, if the argument was a nil pointer, the
result is just "<nil>", because that's almost certainly enough
information and handles the very common case of String
methods that don't guard against nil.
Scan does not want this change. Input must work; output can
be for debugging and it's nice to get output even when you
make a mistake.
R=dsymonds, r, adg, gri, rsc, gri
CC=golang-dev
https://golang.org/cl/4640043
%+q uses strconv.Quote[Rune]ToASCII, guaranteeing ASCII-only output.
%#U a quoted character if the rune is printable: 'x'=U+0078; otherwise
it's as before: U+000A.
R=golang-dev, gri, rsc
CC=golang-dev
https://golang.org/cl/4589047
