diff --git a/src/pkg/go/printer/nodes.go b/src/pkg/go/printer/nodes.go index 1ee0846f68..8aadc75a54 100644 --- a/src/pkg/go/printer/nodes.go +++ b/src/pkg/go/printer/nodes.go @@ -872,7 +872,10 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, ctxt exprContext, multi } p.print(x.Lbrace, token.LBRACE) p.exprList(x.Lbrace, x.Elts, 1, commaSep|commaTerm, multiLine, x.Rbrace) - p.print(x.Rbrace, token.RBRACE) + // do not insert extra line breaks because of comments before + // the closing '}' as it might break the code if there is no + // trailing ',' + p.print(noExtraLinebreak, x.Rbrace, token.RBRACE, noExtraLinebreak) case *ast.Ellipsis: p.print(token.ELLIPSIS) @@ -1388,7 +1391,7 @@ func (p *printer) funcBody(b *ast.BlockStmt, headerSize int, isLit bool, multiLi if isLit { sep = blank } - p.print(sep, b.Pos(), token.LBRACE) + p.print(sep, b.Lbrace, token.LBRACE) if len(b.List) > 0 { p.print(blank) for i, s := range b.List { diff --git a/src/pkg/go/printer/printer.go b/src/pkg/go/printer/printer.go index a4ddad50ec..34b0c4e2dc 100644 --- a/src/pkg/go/printer/printer.go +++ b/src/pkg/go/printer/printer.go @@ -58,6 +58,15 @@ var infinity = 1 << 30 var ignoreMultiLine = new(bool) +// A pmode value represents the current printer mode. +type pmode int + +const ( + inLiteral pmode = 1 << iota + noExtraLinebreak +) + + type printer struct { // Configuration (does not change after initialization) output io.Writer @@ -69,7 +78,7 @@ type printer struct { nesting int // nesting level (0: top-level (package scope), >0: functions/decls.) written int // number of bytes written indent int // current indentation - escape bool // true if in escape sequence + mode pmode // current printer mode lastTok token.Token // the last token printed (token.ILLEGAL if it's whitespace) // Buffered whitespace @@ -162,7 +171,7 @@ func (p *printer) write(data []byte) { p.pos.Line++ p.pos.Column = 1 - if !p.escape { + if p.mode&inLiteral == 0 { // write indentation // use "hard" htabs - indentation columns // must not be discarded by the tabwriter @@ -211,7 +220,7 @@ func (p *printer) write(data []byte) { } case tabwriter.Escape: - p.escape = !p.escape + p.mode ^= inLiteral // ignore escape chars introduced by printer - they are // invisible and must not affect p.pos (was issue #1089) @@ -272,7 +281,7 @@ func (p *printer) writeItem(pos token.Position, data []byte, tag HTMLTag) { // (used when printing merged ASTs of different files // e.g., the result of ast.MergePackageFiles) p.indent = 0 - p.escape = false + p.mode = 0 p.buffer = p.buffer[0:0] fileChanged = true } @@ -683,9 +692,13 @@ func (p *printer) intersperseComments(next token.Position, tok token.Token) (dro // follows on the same line: separate with an extra blank p.write([]byte{' '}) } - // ensure that there is a newline after a //-style comment - // or if we are before a closing '}' or at the end of a file - return p.writeCommentSuffix(last.Text[1] == '/' || tok == token.RBRACE || tok == token.EOF) + // ensure that there is a line break after a //-style comment, + // before a closing '}' unless explicitly disabled, or at eof + needsLinebreak := + last.Text[1] == '/' || + tok == token.RBRACE && p.mode&noExtraLinebreak == 0 || + tok == token.EOF + return p.writeCommentSuffix(needsLinebreak) } // no comment was written - we should never reach here since @@ -787,6 +800,9 @@ func (p *printer) print(args ...interface{}) { var tok token.Token switch x := f.(type) { + case pmode: + // toggle printer mode + p.mode ^= x case whiteSpace: if x == ignore { // don't add ignore's to the buffer; they @@ -818,10 +834,14 @@ func (p *printer) print(args ...interface{}) { data = x.Value } // escape all literals so they pass through unchanged - // (note that valid Go programs cannot contain esc ('\xff') - // bytes since they do not appear in legal UTF-8 sequences) - // TODO(gri): do this more efficiently. - data = []byte("\xff" + string(data) + "\xff") + // (note that valid Go programs cannot contain + // tabwriter.Escape bytes since they do not appear in + // legal UTF-8 sequences) + escData := make([]byte, 0, len(data)+2) + escData = append(escData, tabwriter.Escape) + escData = append(escData, data...) + escData = append(escData, tabwriter.Escape) + data = escData tok = x.Kind case token.Token: s := x.String() diff --git a/src/pkg/go/printer/testdata/comments.golden b/src/pkg/go/printer/testdata/comments.golden index 200ea332f6..a86d661743 100644 --- a/src/pkg/go/printer/testdata/comments.golden +++ b/src/pkg/go/printer/testdata/comments.golden @@ -422,7 +422,7 @@ func _() { func ( /* comment1 */ T /* comment2 */ ) _() {} -func _() { /* one-liner */ +func _() { /* one-line functions with comments are formatted as multi-line functions */ } func _() { @@ -430,6 +430,10 @@ func _() { /* closing curly brace should be on new line */ } +func _() { + _ = []int{0, 1 /* don't introduce a newline after this comment - was issue 1365 */ } +} + // Comments immediately adjacent to punctuation (for which the go/printer // may obly have estimated position information) must remain after the punctuation. diff --git a/src/pkg/go/printer/testdata/comments.input b/src/pkg/go/printer/testdata/comments.input index 4a9ea4742a..14cd4cf7a1 100644 --- a/src/pkg/go/printer/testdata/comments.input +++ b/src/pkg/go/printer/testdata/comments.input @@ -422,12 +422,16 @@ func _() { func (/* comment1 */ T /* comment2 */) _() {} -func _() { /* one-liner */ } +func _() { /* one-line functions with comments are formatted as multi-line functions */ } func _() { _ = 0 /* closing curly brace should be on new line */ } +func _() { + _ = []int{0, 1 /* don't introduce a newline after this comment - was issue 1365 */} +} + // Comments immediately adjacent to punctuation (for which the go/printer // may obly have estimated position information) must remain after the punctuation.