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mirror of https://github.com/golang/go synced 2024-11-13 19:00:25 -07:00

go/printer, gofmt: smarter handling of multi-line raw strings

If a multi-line raw string is the first token on a line, it
should not be indented because the following lines (belonging
to the raw string) are not indented either.

Adjusted src of ebnf/ebnf_test.go manually as it now is formatted
as expected.

gofmt -w src misc

Fixes #1072.

R=r
CC=golang-dev
https://golang.org/cl/4119056
This commit is contained in:
Robert Griesemer 2011-02-04 17:34:16 -08:00
parent 42973dddf4
commit d812e8c994
5 changed files with 311 additions and 40 deletions

View File

@ -15,20 +15,20 @@ var fset = token.NewFileSet()
var grammars = []string{
`Program = .
`,
`Program = .
`,
`Program = foo .
foo = "foo" .
`,
`Program = foo .
foo = "foo" .
`,
`Program = "a" | "b" "c" .
`,
`Program = "a" | "b" "c" .
`,
`Program = "a" ... "z" .
`,
`Program = "a" ... "z" .
`,
`Program = Song .
`Program = Song .
Song = { Note } .
Note = Do | (Re | Mi | Fa | So | La) | Ti .
Do = "c" .
@ -39,7 +39,7 @@ var grammars = []string{
La = "a" .
Ti = ti .
ti = "b" .
`,
`,
}

View File

@ -34,6 +34,12 @@ const (
)
const (
esc2 = '\xfe' // an escape byte that cannot occur in regular UTF-8
_ = 1 / (esc2 - tabwriter.Escape) // cause compiler error if esc2 == tabwriter.Escape
)
var (
esc = []byte{tabwriter.Escape}
htab = []byte{'\t'}
@ -843,6 +849,19 @@ func (p *printer) print(args ...interface{}) {
escData = append(escData, tabwriter.Escape)
data = escData
tok = x.Kind
// If we have a raw string that spans multiple lines and
// the opening quote (`) is on a line preceded only by
// indentation, we don't want to write that indentation
// because the following lines of the raw string are not
// indented. It's easiest to correct the output at the end
// via the trimmer (because of the complex handling of
// white space).
// Mark multi-line raw strings by replacing the opening
// quote with esc2 and have the trimmer take care of fixing
// it up. (Do this _after_ making a copy of data!)
if data[1] == '`' && bytes.IndexByte(data, '\n') > 0 {
data[1] = esc2
}
case token.Token:
s := x.String()
if mayCombine(p.lastTok, s[0]) {
@ -928,20 +947,25 @@ func (p *printer) flush(next token.Position, tok token.Token) (droppedFF bool) {
//
type trimmer struct {
output io.Writer
space bytes.Buffer
state int
space bytes.Buffer
hasText bool
}
// trimmer is implemented as a state machine.
// It can be in one of the following states:
const (
inSpace = iota
inEscape
inText
inSpace = iota // inside space
atEscape // inside space and the last char was an opening tabwriter.Escape
inEscape // inside text bracketed by tabwriter.Escapes
inText // inside text
)
var backquote = []byte{'`'}
// Design note: It is tempting to eliminate extra blanks occurring in
// whitespace in this function as it could simplify some
// of the blanks logic in the node printing functions.
@ -949,7 +973,13 @@ const (
// the tabwriter.
func (p *trimmer) Write(data []byte) (n int, err os.Error) {
m := 0 // if p.state != inSpace, data[m:n] is unwritten
// invariants:
// p.state == inSpace, atEscape:
// p.space is unwritten
// p.hasText indicates if there is any text on this line
// p.state == inEscape, inText:
// data[m:n] is unwritten
m := 0
var b byte
for n, b = range data {
if b == '\v' {
@ -960,37 +990,55 @@ func (p *trimmer) Write(data []byte) (n int, err os.Error) {
switch b {
case '\t', ' ':
p.space.WriteByte(b) // WriteByte returns no errors
case '\f', '\n':
case '\n', '\f':
p.space.Reset() // discard trailing space
_, err = p.output.Write(newlines[0:1]) // write newline
p.hasText = false
case tabwriter.Escape:
_, err = p.output.Write(p.space.Bytes())
p.space.Reset()
p.state = inEscape
m = n + 1 // drop tabwriter.Escape
p.state = atEscape
default:
_, err = p.output.Write(p.space.Bytes())
p.space.Reset()
p.state = inText
m = n
}
case atEscape:
// discard indentation if we have a multi-line raw string
// (see printer.print for details)
if b != esc2 || p.hasText {
_, err = p.output.Write(p.space.Bytes())
}
p.state = inEscape
m = n
if b == esc2 {
_, err = p.output.Write(backquote) // convert back
m++
}
case inEscape:
if b == tabwriter.Escape {
_, err = p.output.Write(data[m:n])
p.state = inSpace
p.space.Reset()
p.hasText = true
}
case inText:
switch b {
case '\t', ' ':
_, err = p.output.Write(data[m:n])
p.state = inSpace
p.space.Reset()
p.space.WriteByte(b) // WriteByte returns no errors
case '\f':
data[n] = '\n' // convert to newline
p.hasText = true
case '\n', '\f':
_, err = p.output.Write(data[m:n])
p.state = inSpace
p.space.Reset()
_, err = p.output.Write(newlines[0:1]) // write newline
p.hasText = false
case tabwriter.Escape:
_, err = p.output.Write(data[m:n])
p.state = inEscape
m = n + 1 // drop tabwriter.Escape
p.state = atEscape
p.space.Reset()
p.hasText = true
}
}
if err != nil {
@ -999,9 +1047,12 @@ func (p *trimmer) Write(data []byte) (n int, err os.Error) {
}
n = len(data)
if p.state != inSpace {
switch p.state {
case inEscape, inText:
_, err = p.output.Write(data[m:n])
p.state = inSpace
p.space.Reset()
p.hasText = true
}
return

View File

@ -247,6 +247,77 @@ they must not be removed`
}
func _() {
// smart handling of indentation for multi-line raw strings
var _ = ``
var _ = `foo`
var _ = `foo
bar`
var _ = ``
var _ = `foo`
var _ =
// the next line should not be indented
`foo
bar`
var _ = // comment
``
var _ = // comment
`foo`
var _ = // comment
// the next line should not be indented
`foo
bar`
var _ = /* comment */ ``
var _ = /* comment */ `foo`
var _ = /* comment */ `foo
bar`
var _ = /* comment */
``
var _ = /* comment */
`foo`
var _ = /* comment */
// the next line should not be indented
`foo
bar`
var board = []int(
`...........
...........
....●●●....
....●●●....
..●●●●●●●..
..●●●○●●●..
..●●●●●●●..
....●●●....
....●●●....
...........
...........
`)
var state = S{
"foo",
// the next line should not be indented
`...........
...........
....●●●....
....●●●....
..●●●●●●●..
..●●●○●●●..
..●●●●●●●..
....●●●....
....●●●....
...........
...........
`,
"bar",
}
}
func _() {
// one-line function literals (body is on a single line)
_ = func() {}

View File

@ -243,6 +243,85 @@ they must not be removed`
}
func _() {
// smart handling of indentation for multi-line raw strings
var _ = ``
var _ = `foo`
var _ = `foo
bar`
var _ =
``
var _ =
`foo`
var _ =
// the next line should not be indented
`foo
bar`
var _ = // comment
``
var _ = // comment
`foo`
var _ = // comment
// the next line should not be indented
`foo
bar`
var _ = /* comment */ ``
var _ = /* comment */ `foo`
var _ = /* comment */ `foo
bar`
var _ = /* comment */
``
var _ = /* comment */
`foo`
var _ = /* comment */
// the next line should not be indented
`foo
bar`
var board = []int(
`...........
...........
....●●●....
....●●●....
..●●●●●●●..
..●●●○●●●..
..●●●●●●●..
....●●●....
....●●●....
...........
...........
`)
var state = S{
"foo",
// the next line should not be indented
`...........
...........
....●●●....
....●●●....
..●●●●●●●..
..●●●○●●●..
..●●●●●●●..
....●●●....
....●●●....
...........
...........
`,
"bar",
}
}
func _() {
// one-line function literals (body is on a single line)
_ = func() {}

View File

@ -243,7 +243,77 @@ func _() {
_ = `foo
bar`
_ = `three spaces before the end of the line starting here:
they must not be removed`
they must not be removed` }
func _() {
// smart handling of indentation for multi-line raw strings
var _ = ``
var _ = `foo`
var _ = `foo
bar`
var _ = ``
var _ = `foo`
var _ =
// the next line should not be indented
`foo
bar`
var _ = // comment
``
var _ = // comment
`foo`
var _ = // comment
// the next line should not be indented
`foo
bar`
var _ = /* comment */ ``
var _ = /* comment */ `foo`
var _ = /* comment */ `foo
bar`
var _ = /* comment */
``
var _ = /* comment */
`foo`
var _ = /* comment */
// the next line should not be indented
`foo
bar`
var board = []int(
`...........
...........
....●●●....
....●●●....
..●●●●●●●..
..●●●○●●●..
..●●●●●●●..
....●●●....
....●●●....
...........
...........
`)
var state = S{
"foo",
// the next line should not be indented
`...........
...........
....●●●....
....●●●....
..●●●●●●●..
..●●●○●●●..
..●●●●●●●..
....●●●....
....●●●....
...........
...........
`,
"bar",
}
}