README
¶
gofmt2
strict version of gofmt improved and idempotent
Desc
Gofmt formats Go programs. This is improved version.
Features
- remove empty lines between import specs in block (-import_whitespaces enabled by default)
- join all import blocks (-join_imports)
- fix lines
- show ast (-ast)
Code style changes to original gofmt
func always separated by an empty line if its not sequential block of one-liners:
func a() {}
func b() {}
<-- added
func c() {
//
}
<-- added
func d() {}
empty blocks are not allowed on multiple lines:
func a() {
} -> func a() {}
func b() {
} -> func b() {}
for {
} -> for {}
switch {
} -> switch {}
no empty lines are allowed before closing right bracket and after opening left bracket:
func a() int {
<-- would be deleted
if {
<-- would be deleted
fmt.Print(1)
<-- would be deleted
}
return 1
<-- would be deleted
}
by default imports in a single block are concatenated.
Usage:
gofmt [flags] [path ...]
The flags are:
-d
Do not print reformatted sources to standard output.
If a file's formatting is different than gofmt's, print diffs
to standard output.
-e
Print all (including spurious) errors.
-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.
-r rule
Apply the rewrite rule to the source before reformatting.
-s
Try to simplify code (after applying the rewrite rule, if any).
-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.
-import_whitespaces
Remove empty lines in import blocks (default true).
-join_imports
Join imports blocks (default false).
-ast
Print AST.
TODO
- rewrite expressions in which
{rvalue ? lvalue} -> {lvalue ? rvalue} - do not allow comments in form
//*,***,/** - surround operators with spaces
- remove unnec tabs for comments
Documentation
¶
Overview ¶
Gofmt formats Go programs. It uses tabs (width = 8) for indentation and blanks for alignment.
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.
Usage:
gofmt [flags] [path ...]
The flags are:
-d Do not print reformatted sources to standard output. If a file's formatting is different than gofmt's, print diffs to standard output. -e Print all (including spurious) errors. -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. -r rule Apply the rewrite rule to the source before reformatting. -s Try to simplify code (after applying the rewrite rule, if any). -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.
Debugging support:
-cpuprofile filename Write cpu profile to the specified file.
The rewrite rule specified with the -r flag must be a string of the form:
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.
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.
Examples ¶
To check files for unnecessary parentheses:
gofmt -r '(a) -> a' -l *.go
To remove the parentheses:
gofmt -r '(a) -> a' -w *.go
To convert the package tree from explicit slice upper bounds to implicit ones:
gofmt -r 'α[β:len(α)] -> α[β:]' -w $GOROOT/src
The simplify command ¶
When invoked with -s gofmt will make the following source transformations where possible.
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.
Notes ¶
Bugs ¶
The implementation of -r is a bit slow.
If -w fails, the restored original file may not have some of the
original file attributes.
Source Files
Directories