gofmt
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gofmt
Overview 概述
Gofmt formats Go programs. It uses tabs for indentation and blanks for alignment. Alignment assumes that an editor is using a fixed-width font.
gofmt可以格式化Go程序。它使用制表符来缩进，使用空白来对齐。对齐的前提是编辑器使用固定宽度的字体。
Without an explicit path, it processes the standard input. Given a file, it operates on that file; given a directory, it operates on all .go files in that directory, recursively. (Files starting with a period are ignored.) By default, gofmt prints the reformatted sources to standard output.
没有明确的路径，它处理标准输入。给定一个文件，它就对该文件进行操作；给定一个目录，它就对该目录中的所有.go文件进行递归操作。(以句号开头的文件被忽略。)默认情况下，gofmt将重新格式化的源文件打印到标准输出。
Usage:
使用方法：
gofmt [flags] [path ...]
The flags are:
标志是：
-d
Do not print reformatted sources to standard output.
If a file's formatting is different than gofmt's, print diffs
to standard output.
=> 不将重新格式化的源文件打印到标准输出。
如果一个文件的格式与gofmt的不同，则将差异打印到标准输出。到标准输出。
-e
Print all (including spurious) errors.
=> 打印所有（包括假的）错误。
-l
Do not print reformatted sources to standard output.
If a file's formatting is different from gofmt's, print its name
to standard output.
=> 不打印重新格式化的来源到标准输出。
如果一个文件的格式与gofmt不同，则打印其名称
到标准输出。
-r rule
Apply the rewrite rule to the source before reformatting.
=> 在重新格式化前对源文件应用重写规则。
-s
Try to simplify code (after applying the rewrite rule, if any).
=> 尝试简化代码（在应用重写规则后，如果有的话）。
-w
Do not print reformatted sources to standard output.
If a file's formatting is different from gofmt's, overwrite it
with gofmt's version. If an error occurred during overwriting,
the original file is restored from an automatic backup.
=> 不将重新格式化的源文件打印到标准输出。
如果一个文件的格式与gofmt的不同，就用gofmt的版本覆盖它。 用gofmt的版本覆盖。如果在覆盖的过程中发生错误。 原始文件将从自动备份中恢复。
Debugging support:
调试支持：
-cpuprofile filename
Write cpu profile to the specified file.
The rewrite rule specified with the -r flag must be a string of the form:
用-r标志指定的重写规则必须是一个形式的字符串：
pattern -> replacement
Both pattern and replacement must be valid Go expressions. In the pattern, single-character lowercase identifiers serve as wildcards matching arbitrary sub-expressions; those expressions will be substituted for the same identifiers in the replacement.
pattern和replacement都必须是有效的Go表达式。在模式中，单字符小写标识符作为通配符匹配任意子表达式；这些表达式将被替换为替换中的相同标识符。
When gofmt reads from standard input, it accepts either a full Go program or a program fragment. A program fragment must be a syntactically valid declaration list, statement list, or expression. When formatting such a fragment, gofmt preserves leading indentation as well as leading and trailing spaces, so that individual sections of a Go program can be formatted by piping them through gofmt.
当gofmt从标准输入读取时，它接受一个完整的Go程序或程序片段。程序片段必须是一个语法上有效的声明列表、语句列表或表达式。当格式化这样的片段时，gofmt 会保留前导缩进以及前导和后导空格，因此 Go 程序的各个部分可以通过 gofmt 的管道来进行格式化。
Examples 例子
To check files for unnecessary parentheses:
检查文件是否有不必要的括号：
gofmt -r '(a) -> a' -l *.go
To remove the parentheses:
要删除括号：
gofmt -r '(a) -> a' -w *.go
To convert the package tree from explicit slice upper bounds to implicit ones:
将包树从明确的片断上界转换为隐含的上界：
gofmt -r 'α[β:len(α)] -> α[β:]' -w $GOROOT/src
The simplify command 简化命令
When invoked with -s gofmt will make the following source transformations where possible.
当与-s一起调用时，gofmt将尽可能地进行以下源转换。
An array, slice, or map composite literal of the form:
[]T{T{}, T{}}
will be simplified to:
[]T{{}, {}}
A slice expression of the form:
s[a:len(s)]
will be simplified to:
s[a:]
A range of the form:
for x, _ = range v {...}
will be simplified to:
for x = range v {...}
A range of the form:
for _ = range v {...}
will be simplified to:
for range v {...}
This may result in changes that are incompatible with earlier versions of Go.
这可能会导致与Go早期版本不兼容的变化。
Notes 注意事项
Bugs
- The implementation of -r is a bit slow.
- -r的实现有点慢。
- If -w fails, the restored original file may not have some of the original file attributes.
- 如果-w失败，恢复的原始文件可能没有一些原始文件的属性。