- 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 Element interface {}
+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);
+}
+
+
+// ----------------------------------------------------------------------------
+// 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/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>");
-		return;
+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));
+		}
+	}
+}
+
 
-	switch x.tok {
-	case Scanner.IDENT:
-		P.Print(x.val);
+// ----------------------------------------------------------------------------
+// Basics
 
-	case Scanner.INT, Scanner.FLOAT, Scanner.STRING:
-		P.Print(x.val);
+func (P *Printer) DoNil(x *AST.Nil) {
+	P.String("?\n");
+}
 
-	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("]");
+func (P *Printer) DoIdent(x *AST.Ident) {
+	P.String(x.val);
+}
 
-	default:
-		// unary or binary expression
-		print("(");
-		if x.x != nil {
-			P.PrintExpr(x.x);
+
+// ----------------------------------------------------------------------------
+// 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");
 	}
-		P.Print(" " + Scanner.TokenName(x.tok) + " ");
-		P.PrintExpr(x.y);
+}
+
+
+// ----------------------------------------------------------------------------
+// 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;
+	}
+
+	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");
 }
 
 
-export func Print(x AST.Expr) {
+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));
+	}
+}
+
+
+// ----------------------------------------------------------------------------
+// Driver
+
+export func Print(x AST.Node) {
 	var P Printer;
-	print("expr = ");
-	(&P).PrintExpr(x);
+	(&P).Print(x);
 	print("\n");
 }
+