- added more semantic checks - more to come

- distinguish float/int literals syntactically
- fixed a tracing bug

R=r
OCL=13906
CL=13906

usr/gri/gosrc/ast.go

@@ -11,6 +11,61 @@ import Universe "universe"
 // ----------------------------------------------------------------------------
 // Expressions
 
+
+export type Literal struct {
+	typ_ *Globals.Type;
+	b bool;
+	i int;
+	f float;
+	s string;
+}
+
+
+func (x *Literal) typ() *Globals.Type {
+	return x.typ_;
+}
+
+
+export func NewLiteral(typ *Globals.Type) *Literal {
+	x := new(Literal);
+	x.typ_ = typ;
+	return x;
+}
+
+
+export var Bad, True, False, Nil *Literal;
+
+
+// NOTE We could use Globals.Object directly if we'd added a typ()
+// method to its interface. However, this would require renaming the
+// typ field everywhere... - Need to think about accessors again.
+export type Object struct {
+	obj *Globals.Object;
+}
+
+
+func (x *Object) typ() *Globals.Type {
+	return x.obj.typ;
+}
+
+
+export func NewObject(obj* Globals.Object) *Object {
+	x := new(Object);
+	x.obj = obj;
+	return x;
+}
+
+
+export type Selector struct {
+	typ_ *Globals.Type;
+}
+
+
+func (x *Selector) typ() *Globals.Type {
+	return x.typ_;
+}
+
+
 export type BinaryExpr struct {
 	typ_ *Globals.Type;
 	op int;
@@ -18,7 +73,6 @@ export type BinaryExpr struct {
 }
 
 
-
 func (x *BinaryExpr) typ() *Globals.Type {
 	return x.typ_;
 }
@@ -37,3 +91,14 @@ export type IfStat struct {
 	then_ Globals.Stat;
 	else_ Globals.Stat;
 }
+
+
+// ----------------------------------------------------------------------------
+// Initialization
+
+func init() {
+	Bad = NewLiteral(Universe.bad_t);
+	True = NewLiteral(Universe.bool_t);  True.b = true;
+	False = NewLiteral(Universe.bool_t);  False.b = false;
+	Nil = NewLiteral(Universe.nil_t);
+}

usr/gri/gosrc/globals.go

@@ -45,18 +45,6 @@ export type Package struct {
 }
 
 
-// TODO This is hideous! We need to have a decent way to do lists.
-// Ideally open arrays that allow '+'.
-
-type Elem struct {
-	next *Elem;
-	val int;
-	str string;
-	obj *Object;
-	typ *Type;
-}
-
-
 export type List struct {
 	len_ int;
 	first, last *Elem;
@@ -98,6 +86,19 @@ export type Stat interface {
 }
 
 
+// TODO This is hideous! We need to have a decent way to do lists.
+// Ideally open arrays that allow '+'.
+
+type Elem struct {
+	next *Elem;
+	val int;
+	str string;
+	obj *Object;
+	typ *Type;
+	expr Expr
+}
+
+
 // ----------------------------------------------------------------------------
 // Creation
 
@@ -249,6 +250,11 @@ func (L *List) AddTyp(typ *Type) {
 }
 
 
+func (L *List) AddExpr(expr Expr) {
+	L.Add().expr = expr;
+}
+
+
 // ----------------------------------------------------------------------------
 // Scope methods
 

usr/gri/gosrc/parser.go

@@ -47,14 +47,14 @@ func (P *Parser) Trace(msg string) {
 	if P.verbose > 0 {
 		P.PrintIndent();
 		print msg, " {\n";
-		P.indent++;
 	}
+	P.indent++;
 }
 
 
 func (P *Parser) Ecart() {
+	P.indent--;
 	if P.verbose > 0 {
-		P.indent--;
 		P.PrintIndent();
 		print "}\n";
 	}
@@ -132,6 +132,9 @@ func (P *Parser) DeclareInScope(scope *Globals.Scope, obj *Globals.Object) {
 	if !P.semantic_checks {
 		return;
 	}
+	if P.level > 0 {
+		panic "cannot declare objects in other packages";
+	}
 	obj.pnolev = P.level;
 	if scope.Lookup(obj.ident) != nil {
 		P.Error(obj.pos, `"` + obj.ident + `" is declared already`);
@@ -200,26 +203,25 @@ func (P *Parser) DeclareFunc(ident string, typ *Globals.Type) *Globals.Object {
 		return obj;
 	}
 
-	// obj != NULL: possibly a forward declaration.
+	// obj != NULL: possibly a forward declaration
 	if obj.kind != Object.FUNC {
 		P.Error(-1, `"` + ident + `" is declared already`);
-		// Continue but do not insert this function into the scope.
+		// continue but do not insert this function into the scope
 		obj = Globals.NewObject(-1, Object.FUNC, ident);
 		obj.typ = typ;
 		// TODO do we need to set the primary type? probably...
 		return obj;
 	}
 
-	// We have a function with the same name.
-	/*
-	if !EqualTypes(type, obj->type()) {
-		this->Error("type of \"%s\" does not match its forward declaration", name.cstr());
-		// Continue but do not insert this function into the scope.
-		NewObject(Object::FUNC, name);
-		obj->set_type(type);
+	// we have a function with the same name
+	if !Type.Equal(typ, obj.typ) {
+		P.Error(-1, `type of "` + ident + `" does not match its forward declaration`);
+		// continue but do not insert this function into the scope
+		obj = Globals.NewObject(-1, Object.FUNC, ident);
+		obj.typ = typ;
+		// TODO do we need to set the primary type? probably...
 		return obj;    
 	}
-	*/
 
 	// We have a matching forward declaration. Use it.
 	return obj;
@@ -826,12 +828,10 @@ func (P *Parser) ParseExpressionList() *Globals.List {
 	P.Trace("ExpressionList");
 	
 	list := Globals.NewList();
-	P.ParseExpression();
-	list.AddInt(0);  // TODO fix this - add correct list element
+	list.AddExpr(P.ParseExpression());
 	for P.tok == Scanner.COMMA {
 		P.Next();
-		P.ParseExpression();
-		list.AddInt(0);  // TODO fix this - add correct list element
+		list.AddExpr(P.ParseExpression());
 	}
 	
 	P.Ecart();
@@ -867,23 +867,36 @@ func (P *Parser) ParseFunctionLit() Globals.Expr {
 }
 
 
-func (P *Parser) ParseExpressionPair() {
+func (P *Parser) ParseSingleExpressionList(list *Globals.List) {
+	P.Trace("SingleExpressionList");
+	
+	list.AddExpr(P.ParseExpression());
+	for P.tok == Scanner.COMMA {
+		P.Next();
+		list.AddExpr(P.ParseExpression());
+	}
+	
+	P.Ecart();
+}
+
+
+func (P *Parser) ParseExpressionPair(list *Globals.List) {
 	P.Trace("ExpressionPair");
 
-	P.ParseExpression();
+	list.AddExpr(P.ParseExpression());
 	P.Expect(Scanner.COLON);
-	P.ParseExpression();
+	list.AddExpr(P.ParseExpression());
 	
 	P.Ecart();
 }
 
 
-func (P *Parser) ParseExpressionPairList() {
+func (P *Parser) ParseExpressionPairList(list *Globals.List) {
 	P.Trace("ExpressionPairList");
 
-	P.ParseExpressionPair();
+	P.ParseExpressionPair(list);
 	for (P.tok == Scanner.COMMA) {
-		P.ParseExpressionPair();
+		P.ParseExpressionPair(list);
 	}
 	
 	P.Ecart();
@@ -916,20 +929,21 @@ func (P *Parser) ParseCompositeLit(typ *Globals.Type) Globals.Expr {
 	}
 	
 	// TODO: should allow trailing ','
+	list := Globals.NewList();
 	if P.tok != paren {
-		P.ParseExpression();
+		list.AddExpr(P.ParseExpression());
 		if P.tok == Scanner.COMMA {
 			P.Next();
 			if P.tok != paren {
-				P.ParseExpressionList();
+				P.ParseSingleExpressionList(list);
 			}
 		} else if P.tok == Scanner.COLON {
 			P.Next();
-			P.ParseExpression();
+			list.AddExpr(P.ParseExpression());
 			if P.tok == Scanner.COMMA {
 				P.Next();
 				if P.tok != paren {
-					P.ParseExpressionPairList();
+					P.ParseExpressionPairList(list);
 				}
 			}
 		}
@@ -951,64 +965,110 @@ func (P *Parser) ParseOperand(pos int, ident string) Globals.Expr {
 		ident = P.val;
 		P.Next();
 	}
-	
+
+	var res Globals.Expr = AST.Bad;
+
 	if pos >= 0 {
 		// TODO set these up properly in the Universe
 		if ident == "panic" || ident == "print" {
-			P.ParseBuiltinCall();
-			goto exit;
+			res = P.ParseBuiltinCall();
+			
+		} else {
+			obj := P.ParseQualifiedIdent(pos, ident);
+			if P.semantic_checks {
+				if obj.kind == Object.TYPE {
+					res = P.ParseCompositeLit(obj.typ);
+				} else {
+					res = AST.NewObject(obj);
+				}
+			}
 		}
+
+	} else {
 	
-		P.ParseQualifiedIdent(pos, ident);
-		// TODO enable code below
-		/*
-		if obj.kind == Object.TYPE {
-			P.ParseCompositeLit(obj.typ);
+		switch P.tok {
+		case Scanner.IDENT:
+			panic "UNREACHABLE";
+			
+		case Scanner.LPAREN:
+			P.Next();
+			res = P.ParseExpression();
+			P.Expect(Scanner.RPAREN);
+			
+		case Scanner.INT:
+			x := AST.NewLiteral(Universe.int_t);
+			x.i = 42;  // TODO set the right value
+			res = x;
+			P.Next();
+
+		case Scanner.FLOAT:
+			x := AST.NewLiteral(Universe.float_t);
+			x.f = 42.0;  // TODO set the right value
+			res = x;
+			P.Next();
+
+		case Scanner.STRING:
+			x := AST.NewLiteral(Universe.string_t);
+			x.s = P.val;  // TODO need to strip quotes, interpret string properly
+			res = x;
+			P.Next();
+
+		case Scanner.NIL:
+			P.Next();
+			res = AST.Nil;
+			
+		case Scanner.IOTA:
+			x := AST.NewLiteral(Universe.int_t);
+			x.i = 42;  // TODO set the right value
+			res = x;
+			P.Next();
+
+		case Scanner.TRUE:
+			P.Next();
+			res = AST.True;
+
+		case Scanner.FALSE:
+			P.Next();
+			res = AST.False;
+			
+		case Scanner.FUNC:
+			res = P.ParseFunctionLit();
+			
+		case Scanner.NEW:
+			res = P.ParseNew();
+			
+		default:
+			typ := P.TryType();
+			if typ != nil {
+				res = P.ParseCompositeLit(typ);
+			} else {
+				P.Error(P.pos, "operand expected");
+				P.Next();  // make progress
+			}
 		}
-		*/
-		goto exit;
-	}
 	
-	switch P.tok {
-	case Scanner.IDENT:
-		panic "UNREACHABLE";
-	case Scanner.LPAREN:
-		P.Next();
-		P.ParseExpression();
-		P.Expect(Scanner.RPAREN);
-	case Scanner.STRING: fallthrough;
-	case Scanner.NUMBER: fallthrough;
-	case Scanner.NIL: fallthrough;
-	case Scanner.IOTA: fallthrough;
-	case Scanner.TRUE: fallthrough;
-	case Scanner.FALSE:
-		P.Next();
-	case Scanner.FUNC:
-		P.ParseFunctionLit();
-	case Scanner.NEW:
-		P.ParseNew();
-	default:
-		typ := P.TryType();
-		if typ != nil {
-			P.ParseCompositeLit(typ);
-		} else {
-			P.Error(P.pos, "operand expected");
-			P.Next();  // make progress
-		}
 	}
-	
-exit:
+
 	P.Ecart();
-	return nil;
+	return res;
 }
 
 
-func (P *Parser) ParseSelectorOrTypeAssertion() Globals.Expr {
+func (P *Parser) ParseSelectorOrTypeAssertion(x Globals.Expr) Globals.Expr {
 	P.Trace("SelectorOrTypeAssertion");
-	
+
+	pos := P.pos;
 	P.Expect(Scanner.PERIOD);
+	if P.semantic_checks {
+		typ := x.typ();
+		if typ.form != Type.STRUCT || typ.form != Type.INTERFACE {
+			P.Error(pos, `"." cannot be applied to this operand`);
+		}
+	}
+	
 	if P.tok == Scanner.IDENT {
-		P.ParseIdent();
+		ident := P.ParseIdent();
+		
 	} else {
 		P.Expect(Scanner.LPAREN);
 		P.ParseType();
@@ -1016,11 +1076,11 @@ func (P *Parser) ParseSelectorOrTypeAssertion() Globals.Expr {
 	}
 	
 	P.Ecart();
-	return nil;
+	return x;
 }
 
 
-func (P *Parser) ParseIndexOrSlice() Globals.Expr {
+func (P *Parser) ParseIndexOrSlice(x Globals.Expr) Globals.Expr {
 	P.Trace("IndexOrSlice");
 	
 	P.Expect(Scanner.LBRACK);
@@ -1032,11 +1092,11 @@ func (P *Parser) ParseIndexOrSlice() Globals.Expr {
 	P.Expect(Scanner.RBRACK);
 	
 	P.Ecart();
-	return nil;
+	return x;
 }
 
 
-func (P *Parser) ParseCall() Globals.Expr {
+func (P *Parser) ParseCall(x Globals.Expr) Globals.Expr {
 	P.Trace("Call");
 	
 	P.Expect(Scanner.LPAREN);
@@ -1046,30 +1106,26 @@ func (P *Parser) ParseCall() Globals.Expr {
 	P.Expect(Scanner.RPAREN);
 	
 	P.Ecart();
-	return nil;
+	return x;
 }
 
 
 func (P *Parser) ParsePrimaryExpr(pos int, ident string) Globals.Expr {
 	P.Trace("PrimaryExpr");
 	
-	P.ParseOperand(pos, ident);
+	x := P.ParseOperand(pos, ident);
 	for {
 		switch P.tok {
-		case Scanner.PERIOD:
-			P.ParseSelectorOrTypeAssertion();
-		case Scanner.LBRACK:
-			P.ParseIndexOrSlice();
-		case Scanner.LPAREN:
-			P.ParseCall();
-		default:
-			P.Ecart();
-			return nil;
+		case Scanner.PERIOD: x = P.ParseSelectorOrTypeAssertion(x);
+		case Scanner.LBRACK: x = P.ParseIndexOrSlice(x);
+		case Scanner.LPAREN: x = P.ParseCall(x);
+		default: goto exit;
 		}
 	}
-	
+
+exit:
 	P.Ecart();
-	return nil;
+	return x;
 }
 
 
@@ -1944,10 +2000,10 @@ func (P *Parser) ParseProgram() {
 	obj := P.ParseIdentDecl(Object.PACKAGE);
 	P.Optional(Scanner.SEMICOLON);
 	
-	{	if P.level != 0 {
+	{	P.OpenScope();
+		if P.level != 0 {
 			panic "incorrect scope level";
 		}
-		P.OpenScope();
 		
 		P.comp.Insert(Globals.NewPackage(P.S.filename, obj, P.top_scope));
 		if P.comp.pkg_ref != 1 {
@@ -1966,10 +2022,11 @@ func (P *Parser) ParseProgram() {
 		
 		P.ResolveUndefTypes();
 		P.MarkExports();
-		P.CloseScope();
+		
 		if P.level != 0 {
 			panic "incorrect scope level";
 		}
+		P.CloseScope();
 	}
 	
 	P.CloseScope();

usr/gri/gosrc/scanner.go

@@ -10,8 +10,9 @@ export const (
 	ILLEGAL = iota;
 	EOF;
 	IDENT;
+	INT;
+	FLOAT;
 	STRING;
-	NUMBER;
 
 	COMMA;
 	COLON;
@@ -116,8 +117,9 @@ export func TokenName(tok int) string {
 	case ILLEGAL: return "illegal";
 	case EOF: return "eof";
 	case IDENT: return "ident";
+	case INT: return "int";
+	case FLOAT: return "float";
 	case STRING: return "string";
-	case NUMBER: return "number";
 
 	case COMMA: return ",";
 	case COLON: return ":";
@@ -537,10 +539,12 @@ func (S *Scanner) ScanMantissa(base int) {
 }
 
 
-func (S *Scanner) ScanNumber(seen_decimal_point bool) string {
+func (S *Scanner) ScanNumber(seen_decimal_point bool) (tok int, val string) {
 	pos := S.chpos;
+	tok = INT;
 	
 	if seen_decimal_point {
+		tok = FLOAT;
 		pos--;  // '.' is one byte
 		S.ScanMantissa(10);
 		goto exponent;
@@ -558,6 +562,7 @@ func (S *Scanner) ScanNumber(seen_decimal_point bool) string {
 			S.ScanMantissa(8);
 			if digit_val(S.ch) < 10 || S.ch == '.' || S.ch == 'e' || S.ch == 'E' {
 				// float
+				tok = FLOAT;
 				goto mantissa;
 			}
 			// octal int
@@ -571,6 +576,7 @@ mantissa:
 	
 	if S.ch == '.' {
 		// float
+		tok = FLOAT;
 		S.Next();
 		S.ScanMantissa(10)
 	}
@@ -578,6 +584,7 @@ mantissa:
 exponent:
 	if S.ch == 'e' || S.ch == 'E' {
 		// float
+		tok = FLOAT;
 		S.Next();
 		if S.ch == '-' || S.ch == '+' {
 			S.Next();
@@ -586,7 +593,7 @@ exponent:
 	}
 	
 exit:
-	return S.src[pos : S.chpos];
+	return tok, S.src[pos : S.chpos];
 }
 
 
@@ -735,18 +742,18 @@ func (S *Scanner) Scan() (tok, pos int, val string) {
 	
 	switch {
 	case is_letter(ch): tok, val = S.ScanIdentifier();
-	case digit_val(ch) < 10: tok, val = NUMBER, S.ScanNumber(false);
+	case digit_val(ch) < 10: tok, val = S.ScanNumber(false);
 	default:
 		S.Next();  // always make progress
 		switch ch {
 		case -1: tok = EOF;
 		case '"': tok, val = STRING, S.ScanString();
-		case '\'': tok, val = NUMBER, S.ScanChar();
+		case '\'': tok, val = INT, S.ScanChar();
 		case '`': tok, val = STRING, S.ScanRawString();
 		case ':': tok = S.Select2(COLON, DEFINE);
 		case '.':
 			if digit_val(S.ch) < 10 {
-				tok, val = NUMBER, S.ScanNumber(true);
+				tok, val = S.ScanNumber(true);
 			} else {
 				tok = PERIOD;
 			}

usr/gri/gosrc/test_scanner.go

@@ -13,7 +13,7 @@ func Scan(filename, src string) {
 	for {
 		tok, pos, val := S.Scan();
 		print pos, ": ", Scanner.TokenName(tok);
-		if tok == Scanner.IDENT || tok == Scanner.NUMBER || tok == Scanner.STRING {
+		if tok == Scanner.IDENT || tok == Scanner.INT || tok == Scanner.FLOAT || tok == Scanner.STRING {
 			print " ", val;
 		}
 		print "\n";

usr/gri/gosrc/type.go

@@ -4,11 +4,15 @@
 
 package Type
 
+import Globals "globals"
+import Object "object"
+
+
 export const /* form */ (
 	// internal types
-	UNDEF = iota; BAD; NIL;
+	UNDEF = iota; VOID; BAD; NIL;
 	// basic types
-	BOOL; UINT; INT; FLOAT; STRING;
+	BOOL; UINT; INT; FLOAT; STRING; INTEGER;
 	// 'any' type
 	ANY;
 	// composite types
@@ -30,6 +34,7 @@ export const /* flag */ (
 export func FormStr(form int) string {
 	switch form {
 	case UNDEF: return "UNDEF";
+	case VOID: return "VOID";
 	case BAD: return "BAD";
 	case NIL: return "NIL";
 	case BOOL: return "BOOL";
@@ -50,3 +55,111 @@ export func FormStr(form int) string {
 	}
 	return "<unknown Type form>";
 }
+
+
+export func Equal(x, y *Globals.Type) bool;
+
+func Equal0(x, y *Globals.Type) bool {
+	if x == y {
+		return true;  // identical types are equal
+	}
+
+	if x.form == BAD || y.form == BAD {
+		return true;  // bad types are always equal (avoid excess error messages)
+	}
+
+	// TODO where to check for *T == nil ?  
+	if x.form != y.form {
+		return false;  // types of different forms are not equal
+	}
+
+	switch x.form {
+	case UNDEF, BAD:
+		break;
+
+	case NIL, BOOL, STRING, ANY:
+		return true;
+
+	case UINT, INT, FLOAT:
+		return x.size == y.size;
+
+	case ARRAY:
+		return
+			x.len_ == y.len_ &&
+			Equal(x.elt, y.elt);
+
+	case MAP:
+		return
+			Equal(x.aux, y.aux) &&
+			Equal(x.elt, y.elt);
+
+	case CHANNEL:
+		return
+			x.flags == y.flags &&
+			Equal(x.elt, y.elt);
+
+	case FUNCTION:
+		{	xp := x.scope.entries;
+			yp := x.scope.entries;
+			if	x.flags != y.flags &&  // function or method
+				x.len_ != y.len_ &&  // number of parameters
+				xp.len_ != yp.len_  // recv + parameters + results
+			{
+				return false;
+			}
+			for p, q := xp.first, yp.first; p != nil; p, q = p.next, q.next {
+				xf := p.obj;
+				yf := q.obj;
+				if xf.kind != Object.VAR || yf.kind != Object.VAR {
+					panic "parameters must be vars";
+				}
+				if !Equal(xf.typ, yf.typ) {
+					return false;
+				}
+			}
+		}
+		return true;
+
+	case STRUCT:
+		/*
+		{	ObjList* xl = &x.scope.list;
+			ObjList* yl = &y.scope.list;
+			if xl.len() != yl.len() {
+				return false;  // scopes of different sizes are not equal
+			}
+			for int i = xl.len(); i-- > 0; {
+				Object* xf = (*xl)[i];
+				Object* yf = (*yl)[i];
+				ASSERT(xf.kind == Object.VAR && yf.kind == Object.VAR);
+				if xf.name != yf.name) || ! EqualTypes(xf.type(), yf.type() {
+					return false;
+				}
+			}
+		}
+		return true;
+		*/
+		// Scopes must be identical for them to be equal.
+		// If we reach here, they weren't.
+		return false;
+
+	case INTERFACE:
+		panic "UNIMPLEMENTED";
+		return false;
+
+	case POINTER, REFERENCE:
+		return Equal(x.elt, y.elt);
+	}
+
+	panic "UNREACHABLE";
+	return false;
+}
+
+
+export func Equal(x, y *Globals.Type) bool {
+	res := Equal0(x, y);
+	// TODO should do the check below only in debug mode
+	if Equal0(y, x) != res {
+		panic "type equality must be symmetric";
+	}
+	return res;
+}

usr/gri/gosrc/universe.go

@@ -32,6 +32,7 @@ export var (
 	float64_t,
 	float80_t,
 	string_t,
+	integer_t,
 	any_t,
 	
 	// alias types
@@ -111,6 +112,7 @@ func init() {
 	float64_t = Register(DeclType(Type.FLOAT, "float64", 8));
 	float80_t = Register(DeclType(Type.FLOAT, "float80", 10));
 	string_t = Register(DeclType(Type.STRING, "string", 8));
+	integer_t = Register(DeclType(Type.INTEGER, "integer", 8));
 	any_t = Register(DeclType(Type.ANY, "any", 8));
 
 	// All but 'byte' should be platform-dependent, eventually.