Allows code that operates on a FlagSet to know the name and error
handling behavior of the FlagSet without having to call FlagSet.Init.
Fixes#17628Fixes#21888
Change-Id: Ib0fe4c8885f9ccdacf5a7fb761d5ecb23f3bb055
Reviewed-on: https://go-review.googlesource.com/70391
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Previously, a multi-line flag usage string would not be indented with the
rest of the usage strings. This made long usage strings difficult to read.
For example, the usage for flag.String("A", "", "1\n2\n3") would be printed
as:
-A 1
2
3
But will now be printed as:
-A 1
2
3
Also fixes a slight error in the FlagSet.PrintDefaults documentation.
Fixes#20799
Change-Id: I4379c6b7590fdb93a2809a01046a0f6ae32c3e5d
Reviewed-on: https://go-review.googlesource.com/66711
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
CommandLine (exported in Go 1.2) has default output of os.Stderr.
Before it was exported, it made sense to have the global Usage func
(the implicit usage func if CommandLine.Usage is nil) hard-code
os.Stderr has its output. But once CommandLine was exported, Usage
should use it if provided.
Fixes#20998
Change-Id: I9e1c0415a563a982634b9808199c9ee175d72f4c
Reviewed-on: https://go-review.googlesource.com/48390
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Implemented by using a reflect-based approach to recognize the zero
value of any non-interface type that implements flag.Value. Interface
types will fall back to the old code.
Fixes#15904.
Change-Id: I594c3bfb30e9ab1aca3e008ef7f70be20aa41a0b
Reviewed-on: https://go-review.googlesource.com/23581
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Four spaces is what works well for both 4- and 8-space tab stops.
Screen with fixed-width font and 4-space tab stops:
http://imgur.com/lps5Lbb
Change-Id: I7d2b813d674c3e0a68f79d63bc5d5ec5bd4f87bb
Reviewed-on: https://go-review.googlesource.com/7503
Reviewed-by: Rob Pike <r@golang.org>
Make PrintDefaults print an easier-to-read format, and allow the user
to control it a bit by putting a hint into the usage string.
Here is the new doc comment for PrintDefaults, which does the work:
PrintDefaults prints, to standard error unless configured otherwise, a
usage message showing the default settings of all defined command-line
flags. For an integer valued flag x, the default output has the form
-x int
usage-message-for-x (default 7)
The usage message will appear on a separate line except for single-
letter boolean flags. Boolean flags omit the type, since they can be
used without an actual value, and the parenthetical default is omitted
if the default is the zero value for the type. The type, here int, can
be replaced by a string of the user's choosing by placing in the usage
string for the flag a back-quoted name; the first such item in the
message is taken to be a parameter name to show in the message and the
back quotes are stripped from the message when displayed. For instance,
given
flag.String("I", "", "search `directory` for include files")
the output will be
-I directory
search directory for include files.
Given
A = flag.Bool("A", false, "for bootstrapping, allow 'any' type")
B = flag.Bool("Alongflagname", false, "disable bounds checking")
C = flag.Bool("C", true, "a boolean defaulting to true")
D = flag.String("D", "", "set relative `path` for local imports")
F = flag.Float64("F", 2.7, "a non-zero float")
G = flag.Float64("G", 0, "a float that defaults to zero")
N = flag.Int("N", 27, "a non-zero int")
Z = flag.Int("Z", 0, "an int that defaults to zero")
T = flag.Duration("deltaT", 0, "a duration")
the old output was
-A=false: for bootstrapping, allow 'any' type
-Alongflagname=false: disable bounds checking
-C=true: a boolean defaulting to true
-D="": set relative `path` for local imports
-F=2.7: a non-zero float
-G=0: a float that defaults to zero
-N=27: a non-zero int
-Z=0: an int that defaults to zero
-deltaT=0: a duration
and the new output is
-A for bootstrapping, allow 'any' type
-Alongflagname
disable bounds checking
-C a boolean defaulting to true (default true)
-D path
set relative path for local imports
-F float
a non-zero float (default 2.7)
-G float
a float that defaults to zero
-N int
a non-zero int (default 27)
-Z int
an int that defaults to zero
-deltaT duration
a duration
Change-Id: I54ab3cd5610d551422b004d95ab78305e06a395d
Reviewed-on: https://go-review.googlesource.com/7330
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Shell scripts depend on the old behavior too often.
It's too late to make this change.
LGTM=bradfitz
R=rsc, bradfitz
CC=golang-codereviews
https://golang.org/cl/161890044
This is a day 1 error in the flag package: It did not check
that a flag was set at most once on the command line.
Because user-defined flags may have more general
properties, the check applies only to the standard flag
types in this package: bool, string, etc.
Fixes#8960.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/156390043
