- snapshot of pretty printer status

- parts of AST built and printed
- no formatting yet

R=r
OCL=15727
CL=15727

usr/gri/pretty/ast.go

@@ -4,14 +4,54 @@
 
 package AST
 
+
 // ----------------------------------------------------------------------------
-// Lists
+// Visitor
+
+export type Visitor interface {
+	// Basics
+	DoNil(x *Nil);
+	DoIdent(x *Ident);
+	
+	// Declarations
+	DoFuncDecl(x *FuncDecl);
+	
+	// Expressions
+	DoBinary(x *Binary);
+	DoUnary(x *Unary);
+	DoLiteral(x *Literal);
+	DoPair(x *Pair);
+	DoIndex(x *Index);
+	DoCall(x *Call);
+	DoSelector(x *Selector);
+	
+	// Statements
+	DoBlock(x *Block);
+	DoExprStat(x *ExprStat);
+	DoAssignment(x *Assignment);
+	DoIf(x *If);
+	DoFor(x *For);
+	DoSwitch(x *Switch);
+	DoReturn(x *Return);
+	
+	// Program
+	DoProgram(x *Program);
+}
+
 
-export type Element interface {}
+// ----------------------------------------------------------------------------
+// An AST Node
+
+export type Node interface {
+	Visit(x Visitor);
+}
 
 
+// ----------------------------------------------------------------------------
+// Lists
+
 export type List struct {
-	a *[] Element
+	a *[] Node
 }
 
 
@@ -20,17 +60,17 @@ func (p *List) len() int {
 }
 
 
-func (p *List) at(i int) Element {
+func (p *List) at(i int) Node {
 	return p.a[i];
 }
 
 
-func (p *List) Add (x Element) {
+func (p *List) Add (x Node) {
 	a := p.a;
 	n := len(a);
 
 	if n == cap(a) {
-		b := new([] interface {}, 2*n);
+		b := new([] Node, 2*n);
 		for i := 0; i < n; i++ {
 			b[i] = a[i];
 		}
@@ -45,15 +85,54 @@ func (p *List) Add (x Element) {
 
 export func NewList() *List {
 	p := new(List);
-	p.a = new([] interface {}, 10);
+	p.a = new([] Node, 10) [0 : 0];
 	return p;
 }
 
 
+// ----------------------------------------------------------------------------
+// Basics
+
+export type Nil struct {
+	// The Node "nil" value
+}
+
+export var NIL *Nil = new(Nil);
+
+
+export type Ident struct {
+	pos int;
+	val string;
+}
+
+
+func (x *Nil)   Visit(v Visitor)  { v.DoNil(x); }
+func (x *Ident) Visit(v Visitor)  { v.DoIdent(x); }
+
+
+// ----------------------------------------------------------------------------
+// Declarations
+
+export type Decl interface {
+	Visit(x Visitor);
+}
+
+
+export type FuncDecl struct {
+	pos int;
+	ident *Ident;
+	body *Block;
+}
+
+
+func (x *FuncDecl) Visit(v Visitor)  { v.DoFuncDecl(x); }
+
+
 // ----------------------------------------------------------------------------
 // Expressions
 
 export type Expr interface {
+	Visit(x Visitor);
 }
 
 
@@ -71,6 +150,13 @@ export type Index struct {
 }
 
 
+export type Call struct {
+	pos int;
+	fun Expr;
+	args *List;
+}
+
+
 export type Pair struct {
 	pos int;
 	x, y Expr;
@@ -98,20 +184,79 @@ export type Literal struct {
 }
 
 
+func (x *Binary)   Visit(v Visitor)  { v.DoBinary(x); }
+func (x *Unary)    Visit(v Visitor)  { v.DoUnary(x); }
+func (x *Literal)  Visit(v Visitor)  { v.DoLiteral(x); }
+func (x *Pair)     Visit(v Visitor)  { v.DoPair(x); }
+func (x *Index)    Visit(v Visitor)  { v.DoIndex(x); }
+func (x *Call)     Visit(v Visitor)  { v.DoCall(x); }
+func (x *Selector) Visit(v Visitor)  { v.DoSelector(x); }
+
+
 // ----------------------------------------------------------------------------
 // Statements
 
+export type Stat interface {
+	Visit(x Visitor);
+}
+
+
+export type Block struct {
+	pos int;
+	stats *List;
+}
+
+
+export type ExprStat struct {
+	expr Expr;
+}
+
+
+export type Assignment struct {
+	pos int;
+	tok int;
+	lhs, rhs *List;
+}
+
+
+export type If struct {
+	pos int;
+	cond Expr;
+	then, else_ *Block;
+}
+
+
+export type For struct {
+}
+
+
+export type Switch struct {
+}
+
+
+export type Return struct {
+	pos int;
+	res *List;
+}
+
+
+func (x *Block)       Visit(v Visitor)  { v.DoBlock(x); }
+func (x *ExprStat)    Visit(v Visitor)  { v.DoExprStat(x); }
+func (x *Assignment)  Visit(v Visitor)  { v.DoAssignment(x); }
+func (x *If)          Visit(v Visitor)  { v.DoIf(x); }
+func (x *For)         Visit(v Visitor)  { v.DoFor(x); }
+func (x *Switch)      Visit(v Visitor)  { v.DoSwitch(x); }
+func (x *Return)      Visit(v Visitor)  { v.DoReturn(x); }
+
 
 // ----------------------------------------------------------------------------
-// Visitor
+// Program
 
-export type Visitor interface {
-  DoBinary(x *Binary);
-  //DoUnary(x *Unary);
-  //DoLiteral(x *Literal);
+export type Program struct {
+	pos int;
+	ident *Ident;
+	decls *List;
 }
 
 
-func (x *Binary)  Visit(v Visitor)  { v.DoBinary(x); }
-//func (x *Unary)   Visit(v Visitor)  { v.DoUnary(x); }
-//func (x *Literal) Visit(v Visitor)  { v.DoLiteral(x); }
+func (x *Program) Visit(v Visitor)  { v.DoProgram(x); }

usr/gri/pretty/parser.go

@@ -6,11 +6,9 @@ package Parser
 
 import Scanner "scanner"
 import AST "ast"
-import Printer "printer"
 
 
 export type Parser struct {
-	silent bool;
 	verbose bool;
 	indent uint;
 	scanner *Scanner.Scanner;
@@ -68,8 +66,7 @@ func (P *Parser) Next() {
 }
 
 
-func (P *Parser) Open(silent, verbose bool, scanner *Scanner.Scanner, tokchan *<-chan *Scanner.Token) {
-	P.silent = silent;
+func (P *Parser) Open(verbose bool, scanner *Scanner.Scanner, tokchan *<-chan *Scanner.Token) {
 	P.verbose = verbose;
 	P.indent = 0;
 	P.scanner = scanner;
@@ -115,15 +112,15 @@ func (P *Parser) CloseScope() {
 
 func (P *Parser) TryType() bool;
 func (P *Parser) ParseExpression() AST.Expr;
-func (P *Parser) TryStatement() bool;
-func (P *Parser) ParseDeclaration();
+func (P *Parser) TryStatement() (AST.Stat, bool);
+func (P *Parser) ParseDeclaration() AST.Decl;
 
 
-func (P *Parser) ParseIdent() *AST.Literal {
+func (P *Parser) ParseIdent() *AST.Ident {
 	P.Trace("Ident");
 
-	ident := new(AST.Literal);
-	ident.pos, ident.tok, ident.val = P.pos, Scanner.IDENT, "";
+	ident := new(AST.Ident);
+	ident.pos, ident.val = P.pos, "";
 	if P.tok == Scanner.IDENT {
 		ident.val = P.val;
 		if P.verbose {
@@ -156,7 +153,7 @@ func (P *Parser) ParseIdentList() int {
 }
 
 
-func (P *Parser) ParseQualifiedIdent(ident *AST.Literal) AST.Expr {
+func (P *Parser) ParseQualifiedIdent(ident *AST.Ident) AST.Expr {
 	P.Trace("QualifiedIdent");
 
 	if ident == nil {
@@ -444,38 +441,59 @@ func (P *Parser) TryType() bool {
 // ----------------------------------------------------------------------------
 // Blocks
 
-func (P *Parser) ParseStatement() {
+func (P *Parser) ParseStatement() AST.Stat {
 	P.Trace("Statement");
-	if !P.TryStatement() {
+	
+	stat, ok := P.TryStatement();
+	if !ok {
 		P.Error(P.pos, "statement expected");
 		P.Next();  // make progress
 	}
 	P.Ecart();
+	
+	return stat;
 }
 
 
-func (P *Parser) ParseStatementList() {
+func (P *Parser) ParseStatementList() *AST.List {
 	P.Trace("StatementList");
-	for P.TryStatement() {
-		P.Optional(Scanner.SEMICOLON);
+	
+	stats := AST.NewList();
+	for {
+		stat, ok := P.TryStatement();
+		if ok {
+			stats.Add(stat);
+			P.Optional(Scanner.SEMICOLON);
+		} else {
+			break;
+		}
 	}
+	
 	P.Ecart();
+	return stats;
 }
 
 
-func (P *Parser) ParseBlock() {
+func (P *Parser) ParseBlock() *AST.Block {
 	P.Trace("Block");
 	
+	pos := P.pos;
 	P.Expect(Scanner.LBRACE);
 	P.OpenScope();
+	
+	var stats *AST.List;
 	if P.tok != Scanner.RBRACE && P.tok != Scanner.SEMICOLON {
-		P.ParseStatementList();
+		stats = P.ParseStatementList();
 	}
 	P.Optional(Scanner.SEMICOLON);
 	P.CloseScope();
 	P.Expect(Scanner.RBRACE);
 	
 	P.Ecart();
+	
+	x := new(AST.Block);
+	x.pos, x.stats = pos, stats;
+	return x;
 }
 
 
@@ -570,51 +588,41 @@ func (P *Parser) ParseCompositeLit() AST.Expr {
 }
 
 
-func (P *Parser) ParseOperand(ident *AST.Literal) AST.Expr {
+func (P *Parser) ParseOperand() AST.Expr {
 	P.Trace("Operand");
 
-	if ident == nil && P.tok == Scanner.IDENT {
-		// no look-ahead yet
-		ident = P.ParseIdent();
-	}
-
 	var z AST.Expr;
+	switch P.tok {
+	case Scanner.IDENT:
+		z = P.ParseIdent();
+		
+	case Scanner.LPAREN:
+		P.Next();
+		z = P.ParseExpression();
+		P.Expect(Scanner.RPAREN);
 
-	if ident != nil {
-		z = ident;
-
-	} else {
-	
-		switch P.tok {
-		case Scanner.LPAREN:
-			P.Next();
-			z = P.ParseExpression();
-			P.Expect(Scanner.RPAREN);
-
-		case Scanner.INT, Scanner.FLOAT, Scanner.STRING:
-			x := new(AST.Literal);
-			x.pos, x.tok, x.val = P.pos, P.tok, P.val;
-			z = x;
-			P.Next();
+	case Scanner.INT, Scanner.FLOAT, Scanner.STRING:
+		x := new(AST.Literal);
+		x.pos, x.tok, x.val = P.pos, P.tok, P.val;
+		z = x;
+		P.Next();
 
-		case Scanner.FUNC:
-			z = P.ParseFunctionLit();
-			
-		case Scanner.HASH:
-			P.Next();
-			P.ParseType();
-			P.ParseCompositeLit();
-			z = nil;
+	case Scanner.FUNC:
+		z = P.ParseFunctionLit();
+		
+	case Scanner.HASH:
+		P.Next();
+		P.ParseType();
+		P.ParseCompositeLit();
+		z = nil;
 
-		default:
-			if P.tok != Scanner.IDENT && P.TryType() {
-				z = P.ParseCompositeLit();
-			} else {
-				P.Error(P.pos, "operand expected");
-				P.Next();  // make progress
-			}
+	default:
+		if P.tok != Scanner.IDENT && P.TryType() {
+			z = P.ParseCompositeLit();
+		} else {
+			P.Error(P.pos, "operand expected");
+			P.Next();  // make progress
 		}
-	
 	}
 
 	P.Ecart();
@@ -670,6 +678,8 @@ func (P *Parser) ParseIndexOrSlice(x AST.Expr) AST.Expr {
 func (P *Parser) ParseCall(x AST.Expr) AST.Expr {
 	P.Trace("Call");
 
+	pos := P.pos;
+	var args *AST.List = nil;
 	P.Expect(Scanner.LPAREN);
 	if P.tok != Scanner.RPAREN {
 	   	// first arguments could be a type if the call is to "new"
@@ -678,27 +688,29 @@ func (P *Parser) ParseCall(x AST.Expr) AST.Expr {
 		// - still a problem for "new(*T)" (the "*")
 		// - possibility: make "new" a keyword again (or disallow "*" types in new)
 		if P.tok != Scanner.IDENT && P.tok != Scanner.LPAREN && P.TryType() {
-		   	if P.tok == Scanner.COMMA {
-			   	 P.Next();
-				 if P.tok != Scanner.RPAREN {
-				    	  P.ParseExpressionList();
-				 }
+			if P.tok == Scanner.COMMA {
+				P.Next();
+				if P.tok != Scanner.RPAREN {
+					args = P.ParseExpressionList();
+				}
 			}
 		} else {
-			P.ParseExpressionList();
+			args = P.ParseExpressionList();
 		}
 	}
 	P.Expect(Scanner.RPAREN);
 	
 	P.Ecart();
-	return x;
+	call := new(AST.Call);
+	call.pos, call.fun, call.args = pos, x, args;
+	return call;
 }
 
 
-func (P *Parser) ParsePrimaryExpr(ident *AST.Literal) AST.Expr {
+func (P *Parser) ParsePrimaryExpr() AST.Expr {
 	P.Trace("PrimaryExpr");
 	
-	x := P.ParseOperand(ident);
+	x := P.ParseOperand();
 	L: for {
 		switch P.tok {
 		case Scanner.PERIOD: x = P.ParseSelectorOrTypeGuard(x);
@@ -716,7 +728,7 @@ func (P *Parser) ParsePrimaryExpr(ident *AST.Literal) AST.Expr {
 func (P *Parser) ParseUnaryExpr() AST.Expr {
 	P.Trace("UnaryExpr");
 	
-	var x AST.Expr;
+	var x AST.Expr = AST.NIL;
 	switch P.tok {
 	case
 		Scanner.ADD, Scanner.SUB,
@@ -727,11 +739,12 @@ func (P *Parser) ParseUnaryExpr() AST.Expr {
 			P.Next();
 			y := P.ParseUnaryExpr();
 
-			x := new(AST.Unary);
-			x.pos, x.tok, x.x = pos, tok, y;
+			z := new(AST.Unary);
+			z.pos, z.tok, z.x = pos, tok, y;
+			x = z;
 			
 		default:
-			x = P.ParsePrimaryExpr(nil);
+			x = P.ParsePrimaryExpr();
 	}
 	
 	P.Ecart();
@@ -759,21 +772,15 @@ func Precedence(tok int) int {
 }
 
 
-func (P *Parser) ParseBinaryExpr(ident *AST.Literal, prec1 int) AST.Expr {
+func (P *Parser) ParseBinaryExpr(prec1 int) AST.Expr {
 	P.Trace("BinaryExpr");
 	
-	var x AST.Expr;
-	if ident != nil {
-		x = P.ParsePrimaryExpr(ident);
-	} else {
-		x = P.ParseUnaryExpr();
-	}
-
+	x := P.ParseUnaryExpr();
 	for prec := Precedence(P.tok); prec >= prec1; prec-- {
 		for Precedence(P.tok) == prec {
 			pos, tok := P.pos, P.tok;
 			P.Next();
-			y := P.ParseBinaryExpr(nil, prec + 1);
+			y := P.ParseBinaryExpr(prec + 1);
 			
 			z := new(AST.Binary);
 			z.pos, z.tok, z.x, z.y = pos, tok, x, y;
@@ -786,12 +793,11 @@ func (P *Parser) ParseBinaryExpr(ident *AST.Literal, prec1 int) AST.Expr {
 }
 
 
-// Expressions where the first token may be an identifier which has already been consumed.
-func (P *Parser) ParseIdentExpression(ident *AST.Literal) AST.Expr {
-	P.Trace("IdentExpression");
+func (P *Parser) ParseExpression() AST.Expr {
+	P.Trace("Expression");
 	indent := P.indent;
 	
-	x := P.ParseBinaryExpr(ident, 1);
+	x := P.ParseBinaryExpr(1);
 	
 	if indent != P.indent {
 		panic("imbalanced tracing code (Expression)");
@@ -802,59 +808,49 @@ func (P *Parser) ParseIdentExpression(ident *AST.Literal) AST.Expr {
 }
 
 
-func (P *Parser) ParseExpression() AST.Expr {
-	P.Trace("Expression");
-	
-	x := P.ParseIdentExpression(nil);
-	
-	if !P.silent {
-		Printer.Print(x);
-	}
-
-	P.Ecart();
-	return x;
-}
-
-
 // ----------------------------------------------------------------------------
 // Statements
 
-func (P *Parser) ParseSimpleStat() {
+func (P *Parser) ParseSimpleStat() AST.Stat {
 	P.Trace("SimpleStat");
 	
-	P.ParseExpressionList();
+	var stat AST.Stat = AST.NIL;
+	x := P.ParseExpressionList();
 	
 	switch P.tok {
 	case Scanner.COLON:
 		// label declaration
 		P.Next();  // consume ":"
 		
-	case Scanner.DEFINE:
-		// variable declaration
-		P.Next();  // consume ":="
-		P.ParseExpressionList();
-		
-	case Scanner.ASSIGN: fallthrough;
-	case Scanner.ADD_ASSIGN: fallthrough;
-	case Scanner.SUB_ASSIGN: fallthrough;
-	case Scanner.MUL_ASSIGN: fallthrough;
-	case Scanner.QUO_ASSIGN: fallthrough;
-	case Scanner.REM_ASSIGN: fallthrough;
-	case Scanner.AND_ASSIGN: fallthrough;
-	case Scanner.OR_ASSIGN: fallthrough;
-	case Scanner.XOR_ASSIGN: fallthrough;
-	case Scanner.SHL_ASSIGN: fallthrough;
-	case Scanner.SHR_ASSIGN:
+	case
+		Scanner.DEFINE, Scanner.ASSIGN, Scanner.ADD_ASSIGN,
+		Scanner.SUB_ASSIGN, Scanner.MUL_ASSIGN, Scanner.QUO_ASSIGN,
+		Scanner.REM_ASSIGN, Scanner.AND_ASSIGN, Scanner.OR_ASSIGN,
+		Scanner.XOR_ASSIGN, Scanner.SHL_ASSIGN, Scanner.SHR_ASSIGN:
+		pos, tok := P.pos, P.tok;
 		P.Next();
-		P.ParseExpressionList();
+		y := P.ParseExpressionList();
+		asgn := new(AST.Assignment);
+		asgn.pos, asgn.tok, asgn.lhs, asgn.rhs = pos, tok, x, y;
+		stat = asgn;
 		
 	default:
 		if P.tok == Scanner.INC || P.tok == Scanner.DEC {
 			P.Next();
+		} else {
+			xstat := new(AST.ExprStat);
+			if x != nil && x.len() > 0 {
+				xstat.expr = x.at(0);
+			} else {
+				// this is a syntax error
+				xstat.expr = AST.NIL;
+			}
+			stat = xstat;
 		}
 	}
 	
 	P.Ecart();
+	return stat;
 }
 
 
@@ -868,15 +864,19 @@ func (P *Parser) ParseGoStat() {
 }
 
 
-func (P *Parser) ParseReturnStat() {
+func (P *Parser) ParseReturnStat() *AST.Return {
 	P.Trace("ReturnStat");
 	
+	ret := new(AST.Return);
+	ret.pos = P.pos;
+	
 	P.Expect(Scanner.RETURN);
 	if P.tok != Scanner.SEMICOLON && P.tok != Scanner.RBRACE {
-		P.ParseExpressionList();
+		ret.res = P.ParseExpressionList();
 	}
 	
 	P.Ecart();
+	return ret;
 }
 
 
@@ -892,8 +892,11 @@ func (P *Parser) ParseControlFlowStat(tok int) {
 }
 
 
-func (P *Parser) ParseIfStat() {
+func (P *Parser) ParseIfStat() *AST.If {
 	P.Trace("IfStat");
+
+	x := new(AST.If);
+	x.pos, x.cond = P.pos, AST.NIL;
 	
 	P.Expect(Scanner.IF);
 	P.OpenScope();
@@ -904,23 +907,27 @@ func (P *Parser) ParseIfStat() {
 		if P.tok == Scanner.SEMICOLON {
 			P.Next();
 			if P.tok != Scanner.LBRACE {
-				P.ParseExpression();
+				x.cond = P.ParseExpression();
 			}
 		}
 	}
-	P.ParseBlock();
+	x.then = P.ParseBlock();
 	if P.tok == Scanner.ELSE {
 		P.Next();
+		b := new(AST.Block);
+		b.stats = AST.NewList();
 		if P.tok == Scanner.IF {
-			P.ParseIfStat();
+			b.stats.Add(P.ParseIfStat());
 		} else {
 			// TODO should be P.ParseBlock()
-			P.ParseStatement();
+			b.stats.Add(P.ParseStatement());
 		}
+		x.else_ = b;
 	}
 	P.CloseScope();
 	
 	P.Ecart();
+	return x;
 }
 
 
@@ -1079,10 +1086,11 @@ func (P *Parser) ParseSelectStat() {
 }
 
 
-func (P *Parser) TryStatement() bool {
+func (P *Parser) TryStatement() (AST.Stat, bool) {
 	P.Trace("Statement (try)");
 	indent := P.indent;
 
+	var stat AST.Stat = AST.NIL;
 	res := true;
 	switch P.tok {
 	case Scanner.CONST: fallthrough;
@@ -1093,17 +1101,17 @@ func (P *Parser) TryStatement() bool {
 		// for now we do not allow local function declarations
 		fallthrough;
 	case Scanner.MUL, Scanner.ARROW, Scanner.IDENT, Scanner.LPAREN:
-		P.ParseSimpleStat();
+		stat = P.ParseSimpleStat();
 	case Scanner.GO:
 		P.ParseGoStat();
 	case Scanner.RETURN:
-		P.ParseReturnStat();
+		stat = P.ParseReturnStat();
 	case Scanner.BREAK, Scanner.CONTINUE, Scanner.GOTO:
 		P.ParseControlFlowStat(P.tok);
 	case Scanner.LBRACE:
-		P.ParseBlock();
+		stat = P.ParseBlock();
 	case Scanner.IF:
-		P.ParseIfStat();
+		stat = P.ParseIfStat();
 	case Scanner.FOR:
 		P.ParseForStat();
 	case Scanner.SWITCH:
@@ -1121,7 +1129,7 @@ func (P *Parser) TryStatement() bool {
 		panic("imbalanced tracing code (Statement)");
 	}
 	P.Ecart();
-	return res;
+	return stat, res;
 }
 
 
@@ -1236,12 +1244,12 @@ func (P *Parser) ParseDecl(exported bool, keyword int) {
 // func (recv) ident (params) type
 // func (recv) ident (params) (results)
 
-func (P *Parser) ParseFuncDecl(exported bool) {
+func (P *Parser) ParseFuncDecl(exported bool) *AST.FuncDecl {
 	P.Trace("FuncDecl");
 	
+	pos := P.pos;
 	P.Expect(Scanner.FUNC);
-	
-	
+
 	P.OpenScope();
 	P.level--;
 
@@ -1260,15 +1268,19 @@ func (P *Parser) ParseFuncDecl(exported bool) {
 	P.level++;
 	P.CloseScope();
 
-
+    var body *AST.Block;
 	if P.tok == Scanner.SEMICOLON {
 		// forward declaration
 		P.Next();
 	} else {
-		P.ParseBlock();
+		body = P.ParseBlock();
 	}
 	
 	P.Ecart();
+	
+	x := new(AST.FuncDecl);
+	x.pos, x.ident, x.body = pos, ident, body;
+	return x;
 }
 
 
@@ -1296,7 +1308,7 @@ func (P *Parser) ParseExportDecl() {
 }
 
 
-func (P *Parser) ParseDeclaration() {
+func (P *Parser) ParseDeclaration() AST.Decl {
 	P.Trace("Declaration");
 	indent := P.indent;
 	
@@ -1310,11 +1322,12 @@ func (P *Parser) ParseDeclaration() {
 		P.Next();
 	}
 	
+	var x AST.Decl = AST.NIL;
 	switch P.tok {
 	case Scanner.CONST, Scanner.TYPE, Scanner.VAR:
 		P.ParseDecl(exported, P.tok);
 	case Scanner.FUNC:
-		P.ParseFuncDecl(exported);
+		x = P.ParseFuncDecl(exported);
 	case Scanner.EXPORT:
 		if exported {
 			P.Error(P.pos, "cannot mark export declaration for export");
@@ -1334,20 +1347,23 @@ func (P *Parser) ParseDeclaration() {
 		panic("imbalanced tracing code (Declaration)");
 	}
 	P.Ecart();
+	return x;
 }
 
 
 // ----------------------------------------------------------------------------
 // Program
 
-func (P *Parser) ParseProgram() {
+func (P *Parser) ParseProgram() *AST.Program {
 	P.Trace("Program");
 	
 	P.OpenScope();
+	pos := P.pos;
 	P.Expect(Scanner.PACKAGE);
-	obj := P.ParseIdent();
+	ident := P.ParseIdent();
 	P.Optional(Scanner.SEMICOLON);
 	
+	decls := AST.NewList();
 	{	P.OpenScope();
 		if P.level != 0 {
 			panic("incorrect scope level");
@@ -1359,7 +1375,7 @@ func (P *Parser) ParseProgram() {
 		}
 		
 		for P.tok != Scanner.EOF {
-			P.ParseDeclaration();
+			decls.Add(P.ParseDeclaration());
 			P.Optional(Scanner.SEMICOLON);
 		}
 		
@@ -1371,4 +1387,8 @@ func (P *Parser) ParseProgram() {
 	
 	P.CloseScope();
 	P.Ecart();
+	
+	x := new(AST.Program);
+	x.pos, x.ident, x.decls = pos, ident, decls;
+	return x;
 }

usr/gri/pretty/pretty.go

@@ -54,8 +54,11 @@ func main() {
 	    }
 
 	    parser := new(Parser.Parser);
-	    parser.Open(silent.BVal(), verbose.BVal(), scanner, tstream);
+	    parser.Open(verbose.BVal(), scanner, tstream);
 
-	    parser.ParseProgram();
+	    prog := parser.ParseProgram();
+		if !silent.BVal() {
+			Printer.Print(prog);
+		}
 	}
 }

usr/gri/pretty/printer.go

@@ -8,58 +8,192 @@ import Scanner "scanner"
 import AST "ast"
 
 
-type Printer struct {
-	
+type Printer /* implements AST.Visitor */ struct {
+	indent int;
 }
 
 
-func (P *Printer) Print(s string) {
+func (P *Printer) String(s string) {
 	print(s);
 }
 
 
-func (P *Printer) PrintExpr(x AST.Expr) {
-/*
-	if x == nil {
-		P.Print("<nil>");
+func (P *Printer) Print(x AST.Node) {
+	x.Visit(P);
+}
+
+
+func (P *Printer) PrintExprList(p *AST.List) {
+	if p != nil {
+		for i := 0; i < p.len(); i++ {
+			if i > 0 {
+				P.String(", ");
+			}
+			P.Print(p.at(i));
+		}
+	}
+}
+
+
+// ----------------------------------------------------------------------------
+// Basics
+
+func (P *Printer) DoNil(x *AST.Nil) {
+	P.String("?\n");
+}
+
+
+func (P *Printer) DoIdent(x *AST.Ident) {
+	P.String(x.val);
+}
+
+
+// ----------------------------------------------------------------------------
+// Declarations
+
+func (P *Printer) DoBlock(x *AST.Block);
+
+func (P *Printer) DoFuncDecl(x *AST.FuncDecl) {
+	P.String("func ");
+	P.DoIdent(x.ident);
+	P.String("(... something here ...) ");
+	if x.body != nil {
+		P.DoBlock(x.body);
+	} else {
+		P.String(";\n");
+	}
+}
+
+
+// ----------------------------------------------------------------------------
+// Expressions
+
+func (P *Printer) DoBinary(x *AST.Binary) {
+	print("(");
+	P.Print(x.x);
+	P.String(" " + Scanner.TokenName(x.tok) + " ");
+	P.Print(x.y);
+	print(")");
+}
+
+
+func (P *Printer) DoUnary(x *AST.Unary) {
+	P.String(Scanner.TokenName(x.tok));
+	P.Print(x.x);
+}
+
+
+func (P *Printer) DoLiteral(x *AST.Literal) {
+	P.String(x.val);
+}
+
+
+func (P *Printer) DoPair(x *AST.Pair) {
+	P.Print(x.x);
+	P.String(" : ");
+	P.Print(x.y);
+}
+
+
+func (P *Printer) DoIndex(x *AST.Index) {
+	P.Print(x.x);
+	P.String("[");
+	P.Print(x.index);
+	P.String("]");
+}
+
+
+func (P *Printer) DoCall(x *AST.Call) {
+	P.Print(x.fun);
+	P.String("(");
+	P.PrintExprList(x.args);
+	P.String(")");
+}
+
+
+func (P *Printer) DoSelector(x *AST.Selector) {
+	P.Print(x.x);
+	P.String(".");
+	P.String(x.field);
+}
+
+
+// ----------------------------------------------------------------------------
+// Statements
+
+func (P *Printer) DoBlock(x *AST.Block) {
+	if x == nil || x.stats == nil {
+		P.String("\n");
 		return;
 	}
-	
-	switch x.tok {
-	case Scanner.IDENT:
-		P.Print(x.val);
-	
-	case Scanner.INT, Scanner.FLOAT, Scanner.STRING:
-		P.Print(x.val);
-		
-	case Scanner.PERIOD:
-		P.PrintExpr(x.x);
-		P.Print(Scanner.TokenName(x.tok));
-		P.PrintExpr(x.y);
-
-	case Scanner.LBRACK:
-		P.PrintExpr(x.x);
-		P.Print("[");
-		P.PrintExpr(x.y);
-		P.Print("]");
-
-	default:
-		// unary or binary expression
-		print("(");
-		if x.x != nil {
-			P.PrintExpr(x.x);
-		}
-		P.Print(" " + Scanner.TokenName(x.tok) + " ");
-		P.PrintExpr(x.y);
-		print(")");
+
+	P.String("{\n");
+	P.indent++;
+	for i := 0; i < x.stats.len(); i++ {
+		P.Print(x.stats.at(i));
+		P.String("\n");
+	}
+	P.indent--;
+	P.String("}\n");
+}
+
+
+func (P *Printer) DoExprStat(x *AST.ExprStat) {
+	P.Print(x.expr);
+}
+
+
+func (P *Printer) DoAssignment(x *AST.Assignment) {
+	P.PrintExprList(x.lhs);
+	P.String(" " + Scanner.TokenName(x.tok) + " ");
+	P.PrintExprList(x.rhs);
+}
+
+
+func (P *Printer) DoIf(x *AST.If) {
+	P.String("if ");
+	P.Print(x.cond);
+	P.DoBlock(x.then);
+	if x.else_ != nil {
+		P.String("else ");
+		P.DoBlock(x.else_);
+	}
+}
+
+
+func (P *Printer) DoFor(x *AST.For) {
+}
+
+
+func (P *Printer) DoSwitch(x *AST.Switch) {
+}
+
+
+func (P *Printer) DoReturn(x *AST.Return) {
+	P.String("return ");
+	P.PrintExprList(x.res);
+}
+
+
+// ----------------------------------------------------------------------------
+// Program
+
+func (P *Printer) DoProgram(x *AST.Program) {
+	P.String("package ");
+	P.DoIdent(x.ident);
+	P.String("\n");
+	for i := 0; i < x.decls.len(); i++ {
+		P.Print(x.decls.at(i));
 	}
-*/
 }
 
 
-export func Print(x AST.Expr) {
+// ----------------------------------------------------------------------------
+// Driver
+
+export func Print(x AST.Node) {
 	var P Printer;
-	print("expr = ");
-	(&P).PrintExpr(x);
+	(&P).Print(x);
 	print("\n");
 }
+