1
0
mirror of https://github.com/golang/go synced 2024-11-12 05:30:21 -07:00

- collect addition source position information in parser

for end of declarations, blocks, parameter lists, etc.
- use extra src positions to more accurately print comments
- fine-tuned low-level printing routine for comments
- added better debugging support

Status:
- comments now appear at the right place (inbetween the right tokens)
- newline control needs improvement (not very hard)
- comment printing disabled for now because pretty is not idempotent
with it; to enable: -comments

R=r
OCL=20079
CL=20079
This commit is contained in:
Robert Griesemer 2008-11-26 17:07:45 -08:00
parent 732b53a1fe
commit d79f687ed8
4 changed files with 199 additions and 153 deletions

View File

@ -36,7 +36,7 @@ export type Expr struct {
// TODO find a more space efficient way to hold these
s string; // identifiers and literals
t *Type; // type expressions, function literal types
block *array.Array; // stats for function literals
block *array.Array; end int; // stats for function literals
}
@ -88,7 +88,7 @@ export type Type struct {
mode int; // channel mode
key *Type; // receiver type, map key
elt *Type; // array element, map or channel value, or pointer base type, result type
list *array.Array; // struct fields, interface methods, function parameters
list *array.Array; end int; // struct fields, interface methods, function parameters
}
@ -136,7 +136,7 @@ export type Stat struct {
Node;
init, post *Stat;
expr *Expr;
block *array.Array;
block *array.Array; end int; // bkock end position
decl *Decl;
}
@ -162,7 +162,7 @@ export type Decl struct {
val *Expr;
// list of *Decl for ()-style declarations
// list of *Stat for func declarations (or nil for forward decl)
list *array.Array;
list *array.Array; end int;
}

View File

@ -399,6 +399,7 @@ func (P *Parser) ParseParameters(ellipsis_ok bool) *AST.Type {
if P.tok != Scanner.RPAREN {
t.list = P.ParseParameterList(ellipsis_ok);
}
t.end = P.pos;
P.Expect(Scanner.RPAREN);
P.Ecart();
@ -434,6 +435,7 @@ func (P *Parser) ParseResult() *AST.Type {
t = AST.NewType(P.pos, Scanner.STRUCT);
t.list = array.New(0);
t.list.Push(AST.NewTypeExpr(typ));
t.end = P.pos;
}
}
@ -453,6 +455,7 @@ func (P *Parser) ParseFunctionType() *AST.Type {
t := AST.NewType(P.pos, Scanner.LPAREN);
t.list = P.ParseParameters(true).list; // TODO find better solution
t.end = P.pos;
t.elt = P.ParseResult();
P.Ecart();
@ -490,6 +493,7 @@ func (P *Parser) ParseInterfaceType() *AST.Type {
P.Expect(Scanner.SEMICOLON);
}
}
t.end = P.pos;
P.Expect(Scanner.RBRACE);
}
@ -536,6 +540,7 @@ func (P *Parser) ParseStructType() *AST.Type {
}
}
P.OptSemicolon();
t.end = P.pos;
P.Expect(Scanner.RBRACE);
}
@ -609,16 +614,17 @@ func (P *Parser) ParseStatementList() *array.Array {
}
func (P *Parser) ParseBlock() *array.Array {
func (P *Parser) ParseBlock() (slist *array.Array, end int) {
P.Trace("Block");
P.Expect(Scanner.LBRACE);
s := P.ParseStatementList();
slist = P.ParseStatementList();
end = P.pos;
P.Expect(Scanner.RBRACE);
P.opt_semi = true;
P.Ecart();
return s;
return slist, end;
}
@ -654,7 +660,7 @@ func (P *Parser) ParseFunctionLit() *AST.Expr {
x.t = P.ParseFunctionType();
P.expr_lev++;
P.scope_lev++;
x.block = P.ParseBlock();
x.block, x.end = P.ParseBlock();
P.scope_lev--;
P.expr_lev--;
@ -1096,7 +1102,7 @@ func (P *Parser) ParseIfStat() *AST.Stat {
P.Trace("IfStat");
s := P.ParseControlClause(Scanner.IF);
s.block = P.ParseBlock();
s.block, s.end = P.ParseBlock();
if P.tok == Scanner.ELSE {
P.Next();
s1 := AST.BadStat;
@ -1117,7 +1123,7 @@ func (P *Parser) ParseIfStat() *AST.Stat {
s1 = P.ParseIfStat();
} else {
s1 = AST.NewStat(P.pos, Scanner.LBRACE);
s1.block = P.ParseBlock();
s1.block, s1.end = P.ParseBlock();
}
s.post = s1;
}
@ -1131,7 +1137,7 @@ func (P *Parser) ParseForStat() *AST.Stat {
P.Trace("ForStat");
s := P.ParseControlClause(Scanner.FOR);
s.block = P.ParseBlock();
s.block, s.end = P.ParseBlock();
P.Ecart();
return s;
@ -1252,7 +1258,7 @@ func (P *Parser) ParseRangeStat() *AST.Stat {
P.ParseIdentList();
P.Expect(Scanner.DEFINE);
s.expr = P.ParseExpression(1);
s.block = P.ParseBlock();
s.block, s.end = P.ParseBlock();
P.Ecart();
return s;
@ -1286,7 +1292,7 @@ func (P *Parser) ParseStatement() *AST.Stat {
s = P.ParseControlFlowStat(P.tok);
case Scanner.LBRACE:
s = AST.NewStat(P.pos, Scanner.LBRACE);
s.block = P.ParseBlock();
s.block, s.end = P.ParseBlock();
case Scanner.IF:
s = P.ParseIfStat();
case Scanner.FOR:
@ -1417,6 +1423,7 @@ func (P *Parser) ParseDecl(exported bool, keyword int) *AST.Decl {
break;
}
}
d.end = P.pos;
P.Expect(Scanner.RPAREN);
P.opt_semi = true;
@ -1459,7 +1466,7 @@ func (P *Parser) ParseFunctionDecl(exported bool) *AST.Decl {
if P.tok == Scanner.LBRACE {
P.scope_lev++;
d.list = P.ParseBlock();
d.list, d.end = P.ParseBlock();
P.scope_lev--;
}

View File

@ -15,25 +15,36 @@ import (
)
var (
debug = flag.Bool("debug", false, nil, "print debugging information");
tabwidth = flag.Int("tabwidth", 4, nil, "tab width");
usetabs = flag.Bool("usetabs", true, nil, "align with tabs instead of blanks");
comments = flag.Bool("comments", false, nil, "enable printing of comments");
)
// ----------------------------------------------------------------------------
// Support
func assert(p bool) {
if !p {
panic("assert failed");
}
}
// ----------------------------------------------------------------------------
// Printer
// A variety of separators which are printed in a delayed fashion;
// depending on the next token.
const (
none = iota;
blank;
tab;
comma;
semicolon;
)
// Additional printing state to control the output. Fine-tuning
// can be achieved by adding more specific state.
const (
inline = iota;
lineend;
funcend;
)
type Printer struct {
// output
writer *tabwriter.Writer;
@ -47,8 +58,8 @@ type Printer struct {
lastpos int; // pos after last string
level int; // true scope level
indent int; // indentation level
semi bool; // pending ";"
newl int; // pending "\n"'s
separator int; // pending separator
state int; // state info
}
@ -87,114 +98,139 @@ func (P *Printer) Printf(format string, s ...) {
if err != nil {
panic("print error - exiting");
}
P.lastpos += n;
}
func (P *Printer) Newline() {
P.Printf("\n");
for i := P.indent; i > 0; i-- {
P.Printf("\t");
}
}
func (P *Printer) String(pos int, s string) {
// correct pos if necessary
if pos == 0 {
pos = P.lastpos; // estimate
}
P.lastpos = pos;
if P.semi && P.level > 0 { // no semicolons at level 0
P.Printf(";");
// --------------------------------
// print pending separator, if any
// - keep track of white space printed for better comment formatting
trailing_blank := false;
trailing_tab := false;
switch P.separator {
case none: // nothing to do
case blank:
P.Printf(" ");
trailing_blank = true;
case tab:
P.Printf("\t");
trailing_tab = true;
case comma:
P.Printf(",");
if P.state == inline {
P.Printf(" ");
trailing_blank = true;
}
case semicolon:
if P.level > 0 { // no semicolons at level 0
P.Printf(";");
if P.state == inline {
P.Printf(" ");
trailing_blank = true;
}
}
default: panic("UNREACHABLE");
}
P.separator = none;
//print("--", pos, "[", s, "]\n");
src_nl := 0;
at_line_begin := false;
// --------------------------------
// interleave comments, if any
nlcount := 0;
for comments.BVal() && P.cpos < pos {
//print("cc", P.cpos, "\n");
// we have a comment/newline that comes before s
// we have a comment/newline that comes before the string
comment := P.comments.At(P.cindex).(*AST.Comment);
ctext := comment.text;
if ctext == "\n" {
// found a newline in src
src_nl++;
// found a newline in src - count them
nlcount++;
} else {
// classify comment
assert(len(ctext) >= 3); // classification char + "//" or "/*"
// classify comment (len(ctext) >= 2)
//-style comment
if src_nl > 0 || P.cpos == 0 {
if nlcount > 0 || P.cpos == 0 {
// only white space before comment on this line
// or file starts with comment
// - indent
P.Printf("\n");
for i := P.indent; i > 0; i-- {
P.Printf("\t");
}
P.Printf("%s", ctext);
P.Newline();
} else {
// black space before comment on this line
if ctext[1] == '/' {
//-style comment
// - put in next cell
P.Printf("\t%s", ctext);
if !trailing_tab {
P.Printf("\t");
}
} else {
/*-style comment */
// - print surrounded by blanks
P.Printf(" %s ", ctext);
if !trailing_blank && !trailing_tab {
P.Printf(" ");
}
ctext += " ";
}
}
if debug.BVal() {
P.Printf("[%d]", P.cpos);
}
P.Printf("%s", ctext);
if ctext[1] == '/' {
//-style comments must end in newline
if P.newl == 0 {
P.newl = 1;
if P.state == inline { // don't override non-inline states
P.state = lineend;
}
/*
// TODO should we set P.newl instead?
P.Printf("\n");
for i := P.indent; i > 0; i-- {
P.Printf("\t");
}
at_line_begin = true;
*/
}
src_nl = 0;
nlcount = 0;
}
P.NextComment();
}
if at_line_begin && P.newl > 0 {
P.newl--;
}
if src_nl > P.newl {
P.newl = src_nl;
// --------------------------------
// adjust formatting depending on state
switch P.state {
case inline: // nothing to do
case funcend:
P.Printf("\n\n");
fallthrough;
case lineend:
P.Newline();
default: panic("UNREACHABLE");
}
P.state = inline;
if P.newl > 2 {
P.newl = 2;
// --------------------------------
// print string
if debug.BVal() {
P.Printf("[%d]", pos);
}
if P.newl > 0 {
P.Printf("\n");
if P.newl > 1 {
for i := P.newl; i > 1; i-- {
P.Printf("\n");
}
}
for i := P.indent; i > 0; i-- {
P.Printf("\t");
}
}
P.Printf("%s", s);
P.semi, P.newl = false, 0;
// --------------------------------
// done
P.lastpos = pos + len(s); // rough estimate
}
func (P *Printer) Blank() {
P.String(0, " ");
func (P *Printer) Separator(separator int) {
P.separator = separator;
P.String(0, "");
}
@ -204,20 +240,17 @@ func (P *Printer) Token(pos int, tok int) {
func (P *Printer) OpenScope(paren string) {
//P.semi, P.newl = false, 0;
P.String(0, paren);
P.level++;
P.indent++;
P.newl = 1;
P.state = lineend;
}
func (P *Printer) CloseScope(paren string) {
func (P *Printer) CloseScope(pos int, paren string) {
P.indent--;
P.semi = false;
P.String(0, paren);
P.String(pos, paren);
P.level--;
P.semi, P.newl = false, 1;
}
@ -242,9 +275,9 @@ func (P *Printer) Parameters(pos int, list *array.Array) {
x := list.At(i).(*AST.Expr);
if i > 0 {
if prev == x.tok || prev == Scanner.TYPE {
P.String(0, ", ");
P.Separator(comma);
} else {
P.Blank();
P.Separator(blank);
}
}
P.Expr(x);
@ -255,7 +288,7 @@ func (P *Printer) Parameters(pos int, list *array.Array) {
}
func (P *Printer) Fields(list *array.Array) {
func (P *Printer) Fields(list *array.Array, end int) {
P.OpenScope("{");
if list != nil {
var prev int;
@ -263,19 +296,20 @@ func (P *Printer) Fields(list *array.Array) {
x := list.At(i).(*AST.Expr);
if i > 0 {
if prev == Scanner.TYPE && x.tok != Scanner.STRING || prev == Scanner.STRING {
P.semi, P.newl = true, 1;
P.separator = semicolon;
P.state = lineend;
} else if prev == x.tok {
P.String(0, ", ");
P.separator = comma;
} else {
P.String(0, "\t");
P.separator = tab;
}
}
P.Expr(x);
prev = x.tok;
}
P.newl = 1;
P.state = lineend;
}
P.CloseScope("}");
P.CloseScope(end, "}");
}
@ -295,8 +329,8 @@ func (P *Printer) Type(t *AST.Type) {
case Scanner.STRUCT, Scanner.INTERFACE:
P.Token(t.pos, t.tok);
if t.list != nil {
P.Blank();
P.Fields(t.list);
P.separator = blank;
P.Fields(t.list, t.end);
}
case Scanner.MAP:
@ -322,7 +356,7 @@ func (P *Printer) Type(t *AST.Type) {
case Scanner.LPAREN:
P.Parameters(t.pos, t.list);
if t.elt != nil {
P.Blank();
P.separator = blank;
P.Parameters(0, t.elt.list);
}
@ -338,7 +372,7 @@ func (P *Printer) Type(t *AST.Type) {
// ----------------------------------------------------------------------------
// Expressions
func (P *Printer) Block(list *array.Array, indent bool);
func (P *Printer) Block(list *array.Array, end int, indent bool);
func (P *Printer) Expr1(x *AST.Expr, prec1 int) {
if x == nil {
@ -358,8 +392,8 @@ func (P *Printer) Expr1(x *AST.Expr, prec1 int) {
// function literal
P.String(x.pos, "func");
P.Type(x.t);
P.Block(x.block, true);
P.newl = 0;
P.Block(x.block, x.end, true);
P.state = inline;
case Scanner.COMMA:
// list
@ -416,9 +450,9 @@ func (P *Printer) Expr1(x *AST.Expr, prec1 int) {
} else {
// binary expression
P.Expr1(x.x, prec);
P.Blank();
P.separator = blank;
P.Token(x.pos, x.tok);
P.Blank();
P.separator = blank;
}
P.Expr1(x.y, prec);
if prec < prec1 {
@ -442,13 +476,13 @@ func (P *Printer) StatementList(list *array.Array) {
if list != nil {
for i, n := 0, list.Len(); i < n; i++ {
P.Stat(list.At(i).(*AST.Stat));
P.newl = 1;
P.state = lineend;
}
}
}
func (P *Printer) Block(list *array.Array, indent bool) {
func (P *Printer) Block(list *array.Array, end int, indent bool) {
P.OpenScope("{");
if !indent {
P.indent--;
@ -457,39 +491,42 @@ func (P *Printer) Block(list *array.Array, indent bool) {
if !indent {
P.indent++;
}
P.CloseScope("}");
P.separator = none;
P.CloseScope(end, "}");
}
func (P *Printer) ControlClause(s *AST.Stat) {
has_post := s.tok == Scanner.FOR && s.post != nil; // post also used by "if"
P.separator = blank;
if s.init == nil && !has_post {
// no semicolons required
if s.expr != nil {
P.Blank();
P.Expr(s.expr);
}
} else {
// all semicolons required
P.Blank();
// (they are not separators, print them explicitly)
if s.init != nil {
P.Stat(s.init);
P.separator = none;
}
P.semi = true;
P.Blank();
P.Printf(";");
P.separator = blank;
if s.expr != nil {
P.Expr(s.expr);
P.separator = none;
}
if s.tok == Scanner.FOR {
P.semi = true;
P.Printf(";");
P.separator = blank;
if has_post {
P.Blank();
P.Stat(s.post);
P.semi = false
}
}
}
P.Blank();
P.separator = blank;
}
@ -500,7 +537,7 @@ func (P *Printer) Stat(s *AST.Stat) {
case Scanner.EXPRSTAT:
// expression statement
P.Expr(s.expr);
P.semi = true;
P.separator = semicolon;
case Scanner.COLON:
// label declaration
@ -508,7 +545,7 @@ func (P *Printer) Stat(s *AST.Stat) {
P.Expr(s.expr);
P.Token(s.pos, s.tok);
P.indent++;
P.semi = false;
P.separator = none;
case Scanner.CONST, Scanner.TYPE, Scanner.VAR:
// declaration
@ -517,52 +554,53 @@ func (P *Printer) Stat(s *AST.Stat) {
case Scanner.INC, Scanner.DEC:
P.Expr(s.expr);
P.Token(s.pos, s.tok);
P.semi = true;
P.separator = semicolon;
case Scanner.LBRACE:
// block
P.Block(s.block, true);
P.Block(s.block, s.end, true);
case Scanner.IF:
P.String(s.pos, "if");
P.ControlClause(s);
P.Block(s.block, true);
P.Block(s.block, s.end, true);
if s.post != nil {
P.newl = 0;
P.String(0, " else ");
P.separator = blank;
P.String(0, "else");
P.separator = blank;
P.Stat(s.post);
}
case Scanner.FOR:
P.String(s.pos, "for");
P.ControlClause(s);
P.Block(s.block, true);
P.Block(s.block, s.end, true);
case Scanner.SWITCH, Scanner.SELECT:
P.Token(s.pos, s.tok);
P.ControlClause(s);
P.Block(s.block, false);
P.Block(s.block, s.end, false);
case Scanner.CASE, Scanner.DEFAULT:
P.Token(s.pos, s.tok);
if s.expr != nil {
P.Blank();
P.separator = blank;
P.Expr(s.expr);
}
P.String(0, ":");
P.indent++;
P.newl = 1;
P.state = lineend;
P.StatementList(s.block);
P.indent--;
P.newl = 1;
P.state = lineend;
case Scanner.GO, Scanner.RETURN, Scanner.FALLTHROUGH, Scanner.BREAK, Scanner.CONTINUE, Scanner.GOTO:
P.Token(s.pos, s.tok);
if s.expr != nil {
P.Blank();
P.separator = blank;
P.Expr(s.expr);
}
P.semi = true;
P.separator = semicolon;
default:
P.Error(s.pos, s.tok, "stat");
@ -580,28 +618,29 @@ func (P *Printer) Declaration(d *AST.Decl, parenthesized bool) {
P.String(d.pos, "export ");
}
P.Token(d.pos, d.tok);
P.Blank();
P.separator = blank;
}
if d.tok != Scanner.FUNC && d.list != nil {
P.OpenScope("(");
for i := 0; i < d.list.Len(); i++ {
P.Declaration(d.list.At(i).(*AST.Decl), true);
P.semi, P.newl = true, 1;
P.separator = semicolon;
P.state = lineend;
}
P.CloseScope(")");
P.CloseScope(d.end, ")");
} else {
if d.tok == Scanner.FUNC && d.typ.key != nil {
P.Parameters(0, d.typ.key.list);
P.Blank();
P.separator = blank;
}
P.Expr(d.ident);
if d.typ != nil {
if d.tok != Scanner.FUNC {
P.Blank();
P.separator = blank;
}
P.Type(d.typ);
}
@ -618,25 +657,19 @@ func (P *Printer) Declaration(d *AST.Decl, parenthesized bool) {
if d.tok != Scanner.FUNC {
panic("must be a func declaration");
}
P.Blank();
P.Block(d.list, true);
P.separator = blank;
P.Block(d.list, d.end, true);
}
if d.tok != Scanner.TYPE {
P.semi = true;
P.separator = semicolon;
}
}
P.newl = 1;
// extra newline after a function declaration
if d.tok == Scanner.FUNC {
P.newl++;
}
// extra newline at the top level
if P.level == 0 {
P.newl++;
P.state = funcend;
} else {
P.state = lineend;
}
}
@ -647,13 +680,11 @@ func (P *Printer) Declaration(d *AST.Decl, parenthesized bool) {
func (P *Printer) Program(p *AST.Program) {
P.String(p.pos, "package ");
P.Expr(p.ident);
P.newl = 2;
P.state = lineend;
for i := 0; i < p.decls.Len(); i++ {
P.Declaration(p.decls.At(i), false);
}
// end program with '\n'
P.newl = 1;
P.state = lineend;
}

View File

@ -21,6 +21,14 @@ var (
)
func f0(a, b int) int {
if a < b {
a = a + 1; // estimate
}
return b;
}
func main() {
// the prologue
for i := 0; i <= 10 /* limit */; i++ {
@ -32,5 +40,5 @@ func main() {
// the epilogue
println("foo"); // foo
println("foobar"); // foobar
var x int;
var x int; // declare x
}