This allows callers to invoke f.Usage() themselves and get the default
usage handler instead of a panic (from calling a nil function).
Fixes#16955.
Change-Id: Ie337fd9e1f85daf78c5eae7b5c41d5ad8c1f89bf
Reviewed-on: https://go-review.googlesource.com/31576
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
The existing implementation of flag values with fmt package uses
more memory and works slower than the implementation with strconv
package.
Change-Id: I9e749179f66d5c50cafe98186641bcdbc546d2db
Reviewed-on: https://go-review.googlesource.com/28914
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Otherwise flag.PrintDefaults will fail when it tries to determine
whether the default is the zero value.
Fixes#16694.
Change-Id: I253fbf11ffc0a9069fd48c2c3cf3074df53e3a03
Reviewed-on: https://go-review.googlesource.com/27003
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@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>
The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.
This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:
$ perl -i -npe 's,^(\s*// .+[a-z]\.) +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.) +([A-Z])')
$ go test go/doc -update
Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This is a subset of https://golang.org/cl/20022 with only the copyright
header lines, so the next CL will be smaller and more reviewable.
Go policy has been single space after periods in comments for some time.
The copyright header template at:
https://golang.org/doc/contribute.html#copyright
also uses a single space.
Make them all consistent.
Change-Id: Icc26c6b8495c3820da6b171ca96a74701b4a01b0
Reviewed-on: https://go-review.googlesource.com/20111
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Adds the clarification that these functions return empty
string if the requested element is not available
Added fullstops
Fixes#11664
Change-Id: I84173862bc785240f7d3ee75a5023673264d172b
Reviewed-on: https://go-review.googlesource.com/12061
Reviewed-by: Rob Pike <r@golang.org>
ContinueOnError is particularly confusing, because it causes
FlagSet.Parse to return as soon as it sees an error. I gather that the
intent is "continue the program" rather than "continue parsing",
compared to exiting or panicking.
Change-Id: I27370ce1f321ea4debcee5b03faff3532495c71a
Reviewed-on: https://go-review.googlesource.com/10740
Reviewed-by: Rob Pike <r@golang.org>
I think "the flag" was a typo, and the word "after" was repetitive.
Change-Id: I81c034ca11a3a778ff1eb4b3af5b96bc525ab985
Reviewed-on: https://go-review.googlesource.com/10195
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Andrew Gerrand <adg@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>
Check for Set error when a boolean flag isn't explicitly given a value.
Fixes#9345
Change-Id: I97a1289f8cf27567d1a726ebe5ef167c800f357c
Reviewed-on: https://go-review.googlesource.com/1897
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Make golint a bit happier
Change-Id: I8a14342f3e492e92bf5efa611f9ef91176624031
Reviewed-on: https://go-review.googlesource.com/1891
Reviewed-by: Minux Ma <minux@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
