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improved handling of expression lists

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R=rsc
DELTA=189  (118 added, 9 deleted, 62 changed)
OCL=35816
CL=35821
This commit is contained in:
Robert Griesemer 2009-10-15 22:52:11 -07:00
parent 4f7aa31862
commit 738c58ca75
7 changed files with 179 additions and 70 deletions
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110
src/pkg/go/printer/printer.go
View File

@ -60,6 +60,10 @@ var (
)
// Use noPos when a position is needed but not known.
var noPos token.Position
// A lineTag is a token.Position that is used to print
// line tag id's of the form "L%d" where %d stands for
// the line indicated by position.
@ -478,6 +482,12 @@ func (p *printer) print(args ...) {
var data []byte;
switch x := f.Interface().(type) {
case whiteSpace:
if x == ignore {
// don't add ignore's to the buffer; they
// may screw up "correcting" unindents (see
// LabeledStmt)
break;
}
i := len(p.buffer);
if i == cap(p.buffer) {
// Whitespace sequences are very short so this should
@ -552,22 +562,25 @@ func (p *printer) flush(next token.Position) {
// Print as many newlines as necessary (but at least min and and at most
// max newlines) to get to the current line. If newSection is set, the
// first newline is printed as a formfeed. Returns true if any line break
// was printed; returns false otherwise.
// max newlines) to get to the current line. ws is printed before the first
// line break. If newSection is set, the first line break is printed as
// formfeed. Returns true if any line break was printed; returns false otherwise.
//
// TODO(gri): Reconsider signature (provide position instead of line)
//
func (p *printer) linebreak(line, min, max int, newSection bool) (printedBreak bool) {
func (p *printer) linebreak(line, min, max int, ws whiteSpace, newSection bool) (printedBreak bool) {
n := line - p.pos.Line;
switch {
case n < min: n = min;
case n > max: n = max;
}
if n > 0 && newSection {
p.print(formfeed);
n--;
printedBreak = true;
if n > 0 {
p.print(ws);
if newSection {
p.print(formfeed);
n--;
printedBreak = true;
}
}
for ; n > 0; n-- {
p.print(newline);
@ -622,7 +635,7 @@ func (p *printer) identList(list []*ast.Ident) {
for i, x := range list {
xlist[i] = x;
}
p.exprList(xlist, commaSep);
p.exprList(noPos, xlist, commaSep);
}
@ -632,7 +645,7 @@ func (p *printer) stringList(list []*ast.BasicLit) {
for i, x := range list {
xlist[i] = x;
}
p.exprList(xlist, noIndent);
p.exprList(noPos, xlist, noIndent);
}
@ -646,8 +659,9 @@ const (
// Print a list of expressions. If the list spans multiple
// source lines, the original line breaks are respected.
func (p *printer) exprList(list []ast.Expr, mode exprListMode) {
// source lines, the original line breaks are respected between
// expressions.
func (p *printer) exprList(prev token.Position, list []ast.Expr, mode exprListMode) {
if len(list) == 0 {
return;
}
@ -656,7 +670,13 @@ func (p *printer) exprList(list []ast.Expr, mode exprListMode) {
p.print(blank);
}
if list[0].Pos().Line == list[len(list)-1].Pos().Line {
// TODO(gri): endLine may be incorrect as it is really the beginning
// of the last list entry. There may be only one, very long
// entry in which case line == endLine.
line := list[0].Pos().Line;
endLine := list[len(list)-1].Pos().Line;
if prev.IsValid() && prev.Line == line && line == endLine {
// all list entries on a single line
for i, x := range list {
if i > 0 {
@ -672,16 +692,18 @@ func (p *printer) exprList(list []ast.Expr, mode exprListMode) {
// list entries span multiple lines;
// use source code positions to guide line breaks
line := list[0].Pos().Line;
// don't add extra indentation if noIndent is set;
// i.e., pretend that the first line is already indented
indented := mode&noIndent != 0;
// there may or may not be a line break before the first list
// element; in any case indent once after the first line break
if p.linebreak(line, 0, 2, true) && !indented {
p.print(htab, indent); // indent applies to next line
indented = true;
ws := ignore;
if mode&noIndent == 0 {
ws = indent;
}
if prev.IsValid() && prev.Line < line && p.linebreak(line, 1, 2, ws, true) {
ws = ignore;
}
for i, x := range list {
prev := line;
line = x.Pos().Line;
@ -690,11 +712,8 @@ func (p *printer) exprList(list []ast.Expr, mode exprListMode) {
p.print(token.COMMA);
}
if prev < line {
// at least one line break, but respect an extra empty line
// in the source
if p.linebreak(x.Pos().Line, 1, 2, true) && !indented {
p.print(htab, indent); // indent applies to next line
indented = true;
if p.linebreak(line, 1, 2, ws, true) {
ws = ignore;
}
} else {
p.print(blank);
@ -704,13 +723,13 @@ func (p *printer) exprList(list []ast.Expr, mode exprListMode) {
}
if mode & commaTerm != 0 {
p.print(token.COMMA);
if indented && mode&noIndent == 0 {
if ws == ignore && mode&noIndent == 0 {
// should always be indented here since we have a multi-line
// expression list - be conservative and check anyway
p.print(unindent);
}
p.print(formfeed); // terminating comma needs a line break to look good
} else if indented && mode&noIndent == 0 {
} else if ws == ignore && mode&noIndent == 0 {
p.print(unindent);
}
}
@ -899,7 +918,7 @@ func (p *printer) binaryExpr(x *ast.BinaryExpr, prec1 int) {
}
// Print collected operations left-to-right, with blanks if necessary.
indented := false;
ws := indent;
p.expr1(x.X, prec);
for list.Len() > 0 {
x = list.Pop().(*ast.BinaryExpr);
@ -910,9 +929,8 @@ func (p *printer) binaryExpr(x *ast.BinaryExpr, prec1 int) {
p.print(blank, x.OpPos, x.Op);
// at least one line break, but respect an extra empty line
// in the source
if p.linebreak(line, 1, 2, false) && !indented {
p.print(htab, indent); // indent applies to next line
indented = true;
if p.linebreak(line, 1, 2, ws, true) {
ws = ignore;
}
} else {
p.print(blank, x.OpPos, x.Op, blank);
@ -925,7 +943,7 @@ func (p *printer) binaryExpr(x *ast.BinaryExpr, prec1 int) {
}
p.expr1(x.Y, prec);
}
if indented {
if ws == ignore {
p.print(unindent);
}
}
@ -1023,13 +1041,13 @@ func (p *printer) expr1(expr ast.Expr, prec1 int) (optSemi bool) {
case *ast.CallExpr:
p.expr1(x.Fun, token.HighestPrec);
p.print(x.Lparen, token.LPAREN);
p.exprList(x.Args, commaSep);
p.exprList(x.Lparen, x.Args, commaSep);
p.print(x.Rparen, token.RPAREN);
case *ast.CompositeLit:
p.expr1(x.Type, token.HighestPrec);
p.print(x.Lbrace, token.LBRACE);
p.exprList(x.Elts, commaSep | commaTerm);
p.exprList(x.Lbrace, x.Elts, commaSep|commaTerm);
p.print(x.Rbrace, token.RBRACE);
case *ast.Ellipsis:
@ -1105,7 +1123,7 @@ func (p *printer) stmtList(list []ast.Stmt, _indent int) {
for i, s := range list {
// _indent == 0 only for lists of switch/select case clauses;
// in those cases each clause is a new section
p.linebreak(s.Pos().Line, 1, maxStmtNewlines, i == 0 || _indent == 0);
p.linebreak(s.Pos().Line, 1, maxStmtNewlines, ignore, i == 0 || _indent == 0);
if !p.stmt(s) {
p.print(token.SEMICOLON);
}
@ -1120,7 +1138,7 @@ func (p *printer) block(s *ast.BlockStmt, indent int) {
p.print(s.Pos(), token.LBRACE);
if len(s.List) > 0 || p.commentBefore(s.Rbrace) {
p.stmtList(s.List, indent);
p.linebreak(s.Rbrace.Line, 1, maxStmtNewlines, true);
p.linebreak(s.Rbrace.Line, 1, maxStmtNewlines, ignore, true);
}
p.print(s.Rbrace, token.RBRACE);
}
@ -1194,7 +1212,7 @@ func (p *printer) stmt(stmt ast.Stmt) (optSemi bool) {
p.print(unindent);
p.expr(s.Label);
p.print(token.COLON, vtab, indent);
p.linebreak(s.Stmt.Pos().Line, 0, 1, true);
p.linebreak(s.Stmt.Pos().Line, 0, 1, ignore, true);
optSemi = p.stmt(s.Stmt);
case *ast.ExprStmt:
@ -1205,9 +1223,9 @@ func (p *printer) stmt(stmt ast.Stmt) (optSemi bool) {
p.print(s.Tok);
case *ast.AssignStmt:
p.exprList(s.Lhs, commaSep);
p.exprList(s.Pos(), s.Lhs, commaSep);
p.print(blank, s.TokPos, s.Tok);
p.exprList(s.Rhs, blankStart | commaSep);
p.exprList(s.TokPos, s.Rhs, blankStart | commaSep);
case *ast.GoStmt:
p.print(token.GO, blank);
@ -1220,7 +1238,7 @@ func (p *printer) stmt(stmt ast.Stmt) (optSemi bool) {
case *ast.ReturnStmt:
p.print(token.RETURN);
if s.Results != nil {
p.exprList(s.Results, blankStart | commaSep);
p.exprList(s.Pos(), s.Results, blankStart | commaSep);
}
case *ast.BranchStmt:
@ -1254,7 +1272,7 @@ func (p *printer) stmt(stmt ast.Stmt) (optSemi bool) {
case *ast.CaseClause:
if s.Values != nil {
p.print(token.CASE);
p.exprList(s.Values, blankStart | commaSep);
p.exprList(s.Pos(), s.Values, blankStart | commaSep);
} else {
p.print(token.DEFAULT);
}
@ -1271,7 +1289,7 @@ func (p *printer) stmt(stmt ast.Stmt) (optSemi bool) {
case *ast.TypeCaseClause:
if s.Types != nil {
p.print(token.CASE);
p.exprList(s.Types, blankStart | commaSep);
p.exprList(s.Pos(), s.Types, blankStart | commaSep);
} else {
p.print(token.DEFAULT);
}
@ -1380,7 +1398,7 @@ func (p *printer) spec(spec ast.Spec, n int, context declContext) {
}
if s.Values != nil {
p.print(blank, token.ASSIGN);
p.exprList(s.Values, blankStart | commaSep);
p.exprList(noPos, s.Values, blankStart | commaSep);
optSemi = false;
}
} else {
@ -1395,7 +1413,7 @@ func (p *printer) spec(spec ast.Spec, n int, context declContext) {
if s.Values != nil {
p.print(vtab);
p.print(token.ASSIGN);
p.exprList(s.Values, blankStart | commaSep);
p.exprList(noPos, s.Values, blankStart | commaSep);
optSemi = false;
extraTabs = 0;
}
@ -1518,7 +1536,7 @@ func (p *printer) file(src *ast.File) {
if prev != tok {
min = 2;
}
p.linebreak(d.Pos().Line, min, maxDeclNewlines, false);
p.linebreak(d.Pos().Line, min, maxDeclNewlines, ignore, false);
p.decl(d, atTop);
}
}
@ -1662,7 +1680,7 @@ func Fprint(output io.Writer, node interface{}, mode uint, tabwidth int) (int, o
p.comment = n.Comments;
p.file(n);
default:
p.errors <- os.NewError(fmt.Sprintf("unsupported node type %T", n));
p.errors <- os.NewError(fmt.Sprintf("printer.Fprint: unsupported node type %T", n));
runtime.Goexit();
}
p.flush(inf);

44
src/pkg/go/printer/testdata/declarations.go vendored
View File

@ -308,6 +308,50 @@ func _() {
}
func _() {
var Universe = Scope {
Names: map[string]*Ident {
// basic types
"bool": nil,
"byte": nil,
"int8": nil,
"int16": nil,
"int32": nil,
"int64": nil,
"uint8": nil,
"uint16": nil,
"uint32": nil,
"uint64": nil,
"float32": nil,
"float64": nil,
"string": nil,
// convenience types
"int": nil,
"uint": nil,
"uintptr": nil,
"float": nil,
// constants
"false": nil,
"true": nil,
"iota": nil,
"nil": nil,
// functions
"cap": nil,
"len": nil,
"new": nil,
"make": nil,
"panic": nil,
"panicln": nil,
"print": nil,
"println": nil,
}
}
}
// formatting of consecutive single-line functions
func _() {}
func _() {}

53
src/pkg/go/printer/testdata/declarations.golden vendored
View File

@ -174,10 +174,13 @@ func _() {
f, ff, fff, ffff int = 0, 1, 2, 3; // comment
)
// respect original line breaks
var _ = []T{T{0x20, "Telugu"}};
var _ = []T{
// respect original line breaks
T{0x20, "Telugu"}};
T{0x20, "Telugu"},
};
var _ = []T{
// respect original line breaks
T{0x20, "Telugu"},
};
}
func _() {
@ -305,6 +308,50 @@ func _() {
}
func _() {
var Universe = Scope{
Names: map[string]*Ident{
// basic types
"bool": nil,
"byte": nil,
"int8": nil,
"int16": nil,
"int32": nil,
"int64": nil,
"uint8": nil,
"uint16": nil,
"uint32": nil,
"uint64": nil,
"float32": nil,
"float64": nil,
"string": nil,
// convenience types
"int": nil,
"uint": nil,
"uintptr": nil,
"float": nil,
// constants
"false": nil,
"true": nil,
"iota": nil,
"nil": nil,
// functions
"cap": nil,
"len": nil,
"new": nil,
"make": nil,
"panic": nil,
"panicln": nil,
"print": nil,
"println": nil,
},
};
}
// formatting of consecutive single-line functions
func _() {}
func _() {}

3
src/pkg/go/printer/testdata/expressions.golden vendored
View File

@ -172,8 +172,7 @@ func (p *parser) charClass() {
func addState(s []state, inst instr, match []int) {
// handle comments correctly in multi-line expressions
for i := 0; i < l; i++ {
if s[i].inst.index() == index &&
// same instruction
if s[i].inst.index() == index && // same instruction
s[i].match[0] < pos { // earlier match already going; leftmost wins
return s;
}

3
src/pkg/go/printer/testdata/expressions.raw vendored
View File

@ -172,8 +172,7 @@ func (p *parser) charClass() {
func addState(s []state, inst instr, match []int) {
// handle comments correctly in multi-line expressions
for i := 0; i < l; i++ {
if s[i].inst.index() == index &&
// same instruction
if s[i].inst.index() == index && // same instruction
s[i].match[0] < pos { // earlier match already going; leftmost wins
return s;
}

33
src/pkg/go/printer/testdata/linebreaks.golden vendored
View File

@ -63,19 +63,22 @@ var writerTests = []*writerTest{
// tar -b 1 -c -f- /tmp/16gig.txt | dd bs=512 count=8 > writer-big.tar
&writerTest{
file: "testdata/writer-big.tar",
entries: []*writerTestEntry{&writerTestEntry{header: &Header{
Name: "tmp/16gig.txt",
Mode: 0640,
Uid: 73025,
Gid: 5000,
Size: 16<<30,
Mtime: 1254699560,
Typeflag: '0',
Uname: "dsymonds",
Gname: "eng",
}
// no contents
}},
entries: []*writerTestEntry{
&writerTestEntry{
header: &Header{
Name: "tmp/16gig.txt",
Mode: 0640,
Uid: 73025,
Gid: 5000,
Size: 16<<30,
Mtime: 1254699560,
Typeflag: '0',
Uname: "dsymonds",
Gname: "eng",
},
// no contents
},
},
},
}
@ -181,9 +184,7 @@ var facts = map[int]string{
func usage() {
fmt.Fprintf(os.Stderr,
// TODO(gri): the 2nd string of this string list should not be indented
// TODO(gri): the 2nd string of this string list should not be indented
"usage: godoc package [name ...]\n"
" godoc -http=:6060\n");
flag.PrintDefaults();

3
src/pkg/go/printer/testdata/statements.golden vendored
View File

@ -35,7 +35,8 @@ func _() {
switch expr {} // no semicolon and parens printed
switch x := expr; {
default:
use(x);
use(
x);
}
switch x := expr; expr {
default: