From fd5718ce82c9dec47ad6243acf3b3cc237df4efa Mon Sep 17 00:00:00 2001 From: Robert Griesemer Date: Wed, 29 Feb 2012 17:25:15 -0800 Subject: [PATCH] go/printer, gofmt: improved comment placement Applied gofmt -w src misc (no changes). Fixes #3147. R=r, rsc CC=golang-dev https://golang.org/cl/5710046 --- src/pkg/go/printer/printer.go | 66 ++++++++-------- src/pkg/go/printer/testdata/comments.golden | 85 +++++++++++++++++++++ src/pkg/go/printer/testdata/comments.input | 85 +++++++++++++++++++++ 3 files changed, 204 insertions(+), 32 deletions(-) diff --git a/src/pkg/go/printer/printer.go b/src/pkg/go/printer/printer.go index 1ab4456e832..a027d32da89 100644 --- a/src/pkg/go/printer/printer.go +++ b/src/pkg/go/printer/printer.go @@ -277,10 +277,9 @@ func (p *printer) writeString(pos token.Position, s string, isLit bool) { // it as is likely to help position the comment nicely. // pos is the comment position, next the position of the item // after all pending comments, prev is the previous comment in -// a group of comments (or nil), and isKeyword indicates if the -// next item is a keyword. +// a group of comments (or nil), and tok is the next token. // -func (p *printer) writeCommentPrefix(pos, next token.Position, prev, comment *ast.Comment, isKeyword bool) { +func (p *printer) writeCommentPrefix(pos, next token.Position, prev, comment *ast.Comment, tok token.Token) { if len(p.output) == 0 { // the comment is the first item to be printed - don't write any whitespace return @@ -335,38 +334,41 @@ func (p *printer) writeCommentPrefix(pos, next token.Position, prev, comment *as // comment on a different line: // separate with at least one line break droppedLinebreak := false - if prev == nil { - // first comment of a comment group - j := 0 - for i, ch := range p.wsbuf { - switch ch { - case blank, vtab: - // ignore any horizontal whitespace before line breaks - p.wsbuf[i] = ignore + j := 0 + for i, ch := range p.wsbuf { + switch ch { + case blank, vtab: + // ignore any horizontal whitespace before line breaks + p.wsbuf[i] = ignore + continue + case indent: + // apply pending indentation + continue + case unindent: + // if this is not the last unindent, apply it + // as it is (likely) belonging to the last + // construct (e.g., a multi-line expression list) + // and is not part of closing a block + if i+1 < len(p.wsbuf) && p.wsbuf[i+1] == unindent { continue - case indent: - // apply pending indentation - continue - case unindent: - // if the next token is a keyword, apply the outdent - // if it appears that the comment is aligned with the - // keyword; otherwise assume the outdent is part of a - // closing block and stop (this scenario appears with - // comments before a case label where the comments - // apply to the next case instead of the current one) - if isKeyword && pos.Column == next.Column { - continue - } - case newline, formfeed: - // TODO(gri): may want to keep formfeed info in some cases - p.wsbuf[i] = ignore - droppedLinebreak = true } - j = i - break + // if the next token is not a closing }, apply the unindent + // if it appears that the comment is aligned with the + // token; otherwise assume the unindent is part of a + // closing block and stop (this scenario appears with + // comments before a case label where the comments + // apply to the next case instead of the current one) + if tok != token.RBRACE && pos.Column == next.Column { + continue + } + case newline, formfeed: + p.wsbuf[i] = ignore + droppedLinebreak = prev == nil // record only if first comment of a group } - p.writeWhitespace(j) + j = i + break } + p.writeWhitespace(j) // determine number of linebreaks before the comment n := 0 @@ -675,7 +677,7 @@ func (p *printer) intersperseComments(next token.Position, tok token.Token) (wro var last *ast.Comment for p.commentBefore(next) { for _, c := range p.comment.List { - p.writeCommentPrefix(p.posFor(c.Pos()), next, last, c, tok.IsKeyword()) + p.writeCommentPrefix(p.posFor(c.Pos()), next, last, c, tok) p.writeComment(c) last = c } diff --git a/src/pkg/go/printer/testdata/comments.golden b/src/pkg/go/printer/testdata/comments.golden index 4c6f1ab8274..d9aa2d82f7d 100644 --- a/src/pkg/go/printer/testdata/comments.golden +++ b/src/pkg/go/printer/testdata/comments.golden @@ -168,6 +168,91 @@ func typeswitch(x interface{}) { // this comment should not be indented } +// +// Indentation of comments after possibly indented multi-line constructs +// (test cases for issue 3147). +// + +func _() { + s := 1 + + 2 + // should be indented like s +} + +func _() { + s := 1 + + 2 // comment + // should be indented like s +} + +func _() { + s := 1 + + 2 // comment + // should be indented like s + _ = 0 +} + +func _() { + s := 1 + + 2 + // should be indented like s + _ = 0 +} + +func _() { + s := 1 + + 2 + + // should be indented like s +} + +func _() { + s := 1 + + 2 // comment + + // should be indented like s +} + +func _() { + s := 1 + + 2 // comment + + // should be indented like s + _ = 0 +} + +func _() { + s := 1 + + 2 + + // should be indented like s + _ = 0 +} + +// Test case from issue 3147. +func f() { + templateText := "a" + // A + "b" + // B + "c" // C + + // should be aligned with f() + f() +} + +// Modified test case from issue 3147. +func f() { + templateText := "a" + // A + "b" + // B + "c" // C + + // may not be aligned with f() (source is not aligned) + f() +} + +// +// Test cases for alignment of lines in general comments. +// + func _() { /* freestanding comment aligned line diff --git a/src/pkg/go/printer/testdata/comments.input b/src/pkg/go/printer/testdata/comments.input index c0f8cca3a92..6084b3fe450 100644 --- a/src/pkg/go/printer/testdata/comments.input +++ b/src/pkg/go/printer/testdata/comments.input @@ -171,6 +171,91 @@ func typeswitch(x interface{}) { // this comment should not be indented } +// +// Indentation of comments after possibly indented multi-line constructs +// (test cases for issue 3147). +// + +func _() { + s := 1 + + 2 +// should be indented like s +} + +func _() { + s := 1 + + 2 // comment + // should be indented like s +} + +func _() { + s := 1 + + 2 // comment + // should be indented like s + _ = 0 +} + +func _() { + s := 1 + + 2 + // should be indented like s + _ = 0 +} + +func _() { + s := 1 + + 2 + +// should be indented like s +} + +func _() { + s := 1 + + 2 // comment + + // should be indented like s +} + +func _() { + s := 1 + + 2 // comment + + // should be indented like s + _ = 0 +} + +func _() { + s := 1 + + 2 + + // should be indented like s + _ = 0 +} + +// Test case from issue 3147. +func f() { + templateText := "a" + // A + "b" + // B + "c" // C + + // should be aligned with f() + f() +} + +// Modified test case from issue 3147. +func f() { + templateText := "a" + // A + "b" + // B + "c" // C + + // may not be aligned with f() (source is not aligned) + f() +} + +// +// Test cases for alignment of lines in general comments. +// + func _() { /* freestanding comment aligned line