1. type switches

2. fixed fault on bug128
3. got rid of typeof
4. fixed bug in t,ok = I2T

R=r
OCL=25873
CL=25873

src/cmd/gc/go.h

@@ -329,7 +329,7 @@ enum
 	OKEY, OPARAM,
 	OCOMPOS,
 	OCONV,
-	ODOTTYPE,
+	ODOTTYPE, OTYPESW,
 	OBAD,
 
 	OEXTEND,	// 6g internal
@@ -526,6 +526,7 @@ EXTERN	Node*	retnil;
 EXTERN	Node*	fskel;
 
 EXTERN	Node*	addtop;
+EXTERN	Node*	typeswvar;
 
 EXTERN	char*	context;
 EXTERN	char*	pkgcontext;

src/cmd/gc/go.y

@@ -18,7 +18,7 @@
 %token	<sym>		LPACKAGE LIMPORT LDEFER
 %token	<sym>		LMAP LCHAN LINTERFACE LFUNC LSTRUCT
 %token	<sym>		LCOLAS LFALL LRETURN LDDD
-%token	<sym>		LLEN LCAP LTYPEOF LPANIC LPANICN LPRINT LPRINTN
+%token	<sym>		LLEN LCAP LPANIC LPANICN LPRINT LPRINTN
 %token	<sym>		LVAR LTYPE LCONST LCONVERT LSELECT LMAKE LNEW
 %token	<sym>		LFOR LIF LELSE LSWITCH LCASE LDEFAULT
 %token	<sym>		LBREAK LCONTINUE LGO LGOTO LRANGE
@@ -419,6 +419,10 @@ simple_stmt:
 	{
 		if(addtop != N)
 			fatal("exprsym3_list_r LCOLAS expr_list");
+		if($3->op == OTYPESW) {
+			$$ = nod(OTYPESW, $1, $3->left);
+			break;
+		}
 		$$ = rev($1);
 		$$ = colas($$, $3);
 		$$ = nod(OAS, $$, $3);
@@ -507,6 +511,18 @@ complex_stmt:
 		$$ = nod(OXCASE, $$, N);
 		addtotop($$);
 	}
+|	LCASE type ':'
+	{
+		poptodcl();
+		if(typeswvar == N || typeswvar->right == N) {
+			yyerror("type case not in a type switch");
+			$$ = N;
+		} else
+			$$ = old2new(typeswvar->right, $2);
+		$$ = nod(OTYPESW, $$, N);
+		$$ = nod(OXCASE, $$, N);
+		addtotop($$);
+	}
 |	LDEFAULT ':'
 	{
 		poptodcl();
@@ -648,10 +664,20 @@ if_header:
 	}
 
 if_body:
-	if_header compound_stmt
+	if_header
+	{
+		Node *n;
+		n = $1->ntest;
+		if(n != N && n->op == OTYPESW)
+			n = n->left;
+		else
+			n = N;
+		typeswvar = nod(OLIST, typeswvar, n);
+	} compound_stmt
 	{
 		$$ = $1;
-		$$->nbody = $2;
+		$$->nbody = $3;
+		typeswvar = typeswvar->left;
 	}
 
 if_stmt:
@@ -836,6 +862,10 @@ pexpr:
 		$$ = nod(ODOTTYPE, $1, N);
 		$$->type = $4;
 	}
+|	pexpr '.' '(' LTYPE ')'
+	{
+		$$ = nod(OTYPESW, $1, N);
+	}
 |	pexpr '[' expr ']'
 	{
 		$$ = nod(OINDEX, $1, $3);
@@ -858,11 +888,6 @@ pexpr:
 	{
 		$$ = nod(OCAP, $3, N);
 	}
-|	LTYPEOF '(' type ')'
-	{
-		$$ = nod(OTYPEOF, N, N);
-		$$->type = $3;
-	}
 |	LNEW '(' type ')'
 	{
 		$$ = nod(ONEW, N, N);
@@ -1001,7 +1026,6 @@ sym3:
 |	LNEW
 |	LMAKE
 |	LBASETYPE
-|	LTYPEOF
 
 /*
  * keywords that we can

src/cmd/gc/lex.c

@@ -1110,7 +1110,6 @@ static	struct
 	"switch",	LSWITCH,	Txxx,
 	"true",		LTRUE,		Txxx,
 	"type",		LTYPE,		Txxx,
-	"typeof",	LTYPEOF,	Txxx,
 	"var",		LVAR,		Txxx,
 
 	"notwithstanding",		LIGNORE,	Txxx,

src/cmd/gc/subr.c

@@ -715,6 +715,7 @@ opnames[] =
 	[OSELECT]	= "SELECT",
 	[OSWITCH]	= "SWITCH",
 	[OTYPE]		= "TYPE",
+	[OTYPESW]	= "TYPESW",
 	[OVAR]		= "VAR",
 	[OIMPORT]	= "IMPORT",
 	[OXOR]		= "XOR",

src/cmd/gc/swt.c

@@ -4,19 +4,38 @@
 
 #include	"go.h"
 
+enum
+{
+	Snorm		= 0,
+	Strue,
+	Sfalse,
+	Stype,
+};
+
 /*
  * walktype
  */
 Type*
-sw0(Node *c, Type *place)
+sw0(Node *c, Type *place, int arg)
 {
 	Node *r;
 
 	if(c == N)
 		return T;
-	if(c->op != OAS) {
+	switch(c->op) {
+	default:
+		if(arg == Stype) {
+			yyerror("inappropriate case for a type switch");
+			return T;
+		}
 		walktype(c, Erv);
 		return T;
+	case OTYPESW:
+		if(arg != Stype)
+			yyerror("inappropriate type case");
+		return T;
+	case OAS:
+		break;
 	}
 	walktype(c->left, Elv);
 
@@ -47,6 +66,8 @@ sw0(Node *c, Type *place)
 		break;
 	}
 	c->type = types[TBOOL];
+	if(arg != Strue)
+		goto bad;
 	return T;
 
 bad:
@@ -58,7 +79,7 @@ bad:
  * return the first type
  */
 Type*
-sw1(Node *c, Type *place)
+sw1(Node *c, Type *place, int arg)
 {
 	if(place == T)
 		return c->type;
@@ -69,7 +90,7 @@ sw1(Node *c, Type *place)
  * return a suitable type
  */
 Type*
-sw2(Node *c, Type *place)
+sw2(Node *c, Type *place, int arg)
 {
 	return types[TINT];	// botch
 }
@@ -79,7 +100,7 @@ sw2(Node *c, Type *place)
  * is compat with all the cases
  */
 Type*
-sw3(Node *c, Type *place)
+sw3(Node *c, Type *place, int arg)
 {
 	if(place == T)
 		return c->type;
@@ -97,7 +118,7 @@ sw3(Node *c, Type *place)
  * types to cases and switch
  */
 Type*
-walkcases(Node *sw, Type*(*call)(Node*, Type*))
+walkcases(Node *sw, Type*(*call)(Node*, Type*, int arg), int arg)
 {
 	Iter save;
 	Node *n;
@@ -105,10 +126,10 @@ walkcases(Node *sw, Type*(*call)(Node*, Type*))
 	int32 lno;
 
 	lno = setlineno(sw);
-	place = call(sw->ntest, T);
+	place = call(sw->ntest, T, arg);
 
 	n = listfirst(&save, &sw->nbody->left);
-	if(n->op == OEMPTY)
+	if(n == N || n->op == OEMPTY)
 		return T;
 
 loop:
@@ -122,7 +143,7 @@ loop:
 
 	if(n->left != N) {
 		setlineno(n->left);
-		place = call(n->left, place);
+		place = call(n->left, place, arg);
 	}
 	n = listnext(&save);
 	goto loop;
@@ -190,6 +211,7 @@ loop:
 		if(oc == N && os != N)
 			yyerror("first switch statement must be a case");
 
+		// botch - shouldnt fall thru declaration
 		if(os != N && os->op == OXFALL)
 			os->op = OFALL;
 		else
@@ -236,23 +258,17 @@ loop:
  * rebulid case statements into if .. goto
  */
 void
-prepsw(Node *sw)
+prepsw(Node *sw, int arg)
 {
 	Iter save;
-	Node *name, *cas;
+	Node *name, *bool, *cas;
 	Node *t, *a;
-	int bool;
-
-	bool = 0;
-	if(whatis(sw->ntest) == Wlitbool) {
-		bool = 1;		// true
-		if(sw->ntest->val.u.xval == 0)
-			bool = 2;	// false
-	}
 
 	cas = N;
 	name = N;
-	if(bool == 0) {
+	bool = N;
+
+	if(arg != Strue && arg != Sfalse) {
 		name = nod(OXXX, N, N);
 		tempname(name, sw->ntest->type);
 		cas = nod(OAS, name, sw->ntest);
@@ -263,7 +279,6 @@ prepsw(Node *sw)
 loop:
 	if(t == N) {
 		sw->nbody->left = rev(cas);
-		walkstate(sw->nbody->left);
 //dump("case", sw->nbody->left);
 		return;
 	}
@@ -274,22 +289,40 @@ loop:
 		goto loop;
 	}
 
+	if(t->left->op == OAS) {
+		if(bool == N) {
+			bool = nod(OXXX, N, N);
+			tempname(bool, types[TBOOL]);
+		}
+//dump("oas", t);
+		t->left->left = nod(OLIST, t->left->left, bool);
+		cas = list(cas, t->left);		// v,bool = rhs
+
+		a = nod(OIF, N, N);
+		a->nbody = t->right;			// then goto l
+		a->ntest = bool;
+		if(arg != Strue)
+			a->ntest = nod(ONOT, bool, N);
+		cas = list(cas, a);			// if bool goto l
+
+		t = listnext(&save);
+		goto loop;
+	}
+
 	a = nod(OIF, N, N);
 	a->nbody = t->right;				// then goto l
 
-	switch(bool) {
+	switch(arg) {
 	default:
 		// not bool const
 		a->ntest = nod(OEQ, name, t->left);	// if name == val
 		break;
 
-	case 1:
-		// bool true
+	case Strue:
 		a->ntest = t->left;			// if val
 		break;
 
-	case 2:
-		// bool false
+	case Sfalse:
 		a->ntest = nod(ONOT, t->left, N);	// if !val
 		break;
 	}
@@ -299,35 +332,141 @@ loop:
 	goto loop;
 }
 
+/*
+ * convert switch of the form
+ *	switch v := i.(type) { case t1: ..; case t2: ..; }
+ * into if statements
+ */
 void
-walkswitch(Node *n)
+typeswitch(Node *sw)
+{
+	Iter save;
+	Node *face, *bool, *cas;
+	Node *t, *a, *b;
+
+//dump("typeswitch", sw);
+
+	walktype(sw->ntest->right, Erv);
+	if(!istype(sw->ntest->right->type, TINTER)) {
+		yyerror("type switch must be on an interface");
+		return;
+	}
+	walkcases(sw, sw0, Stype);
+
+	/*
+	 * predeclare variables for the interface var
+	 * and the boolean var
+	 */
+	face = nod(OXXX, N, N);
+	tempname(face, sw->ntest->right->type);
+	cas = nod(OAS, face, sw->ntest->right);
+
+	bool = nod(OXXX, N, N);
+	tempname(bool, types[TBOOL]);
+
+	t = listfirst(&save, &sw->nbody->left);
+
+loop:
+	if(t == N) {
+		sw->nbody->left = rev(cas);
+		walkstate(sw->nbody);
+//dump("done", sw->nbody->left);
+		return;
+	}
+
+	if(t->left == N) {
+		cas = list(cas, t->right);		// goto default
+		t = listnext(&save);
+		goto loop;
+	}
+	if(t->left->op != OTYPESW) {
+		t = listnext(&save);
+		goto loop;
+	}
+
+	a = t->left->left;		// var
+	a = nod(OLIST, a, bool);	// var,bool
+
+	b = nod(ODOTTYPE, face, N);
+	b->type = t->left->left->type;	// interface.(type)
+
+	a = nod(OAS, a, b);		// var,bool = interface.(type)
+	cas = list(cas, a);
+
+	a = nod(OIF, N, N);
+	a->ntest = bool;
+	a->nbody = t->right;		// if bool { goto l }
+	cas = list(cas, a);
+
+	t = listnext(&save);
+	goto loop;
+}
+
+void
+walkswitch(Node *sw)
 {
 	Type *t;
+	int arg;
 
-	casebody(n);
-	if(n->ntest == N)
-		n->ntest = booltrue;
+//dump("walkswitch", sw);
 
-	walkstate(n->ninit);
-	walktype(n->ntest, Erv);
-	walkstate(n->nbody);
+	/*
+	 * reorder the body into (OLIST, cases, statements)
+	 * cases have OGOTO into statements.
+	 * both have inserted OBREAK statements
+	 */
+	walkstate(sw->ninit);
+	if(sw->ntest == N)
+		sw->ntest = booltrue;
+	casebody(sw);
 
-	// walktype
-	walkcases(n, sw0);
-
-	// find common type
-	t = n->ntest->type;
-	if(t == T)
-		t = walkcases(n, sw1);
-
-	// if that fails pick a type
-	if(t == T)
-		t = walkcases(n, sw2);
-
-	// set the type on all literals
-	if(t != T) {
-		walkcases(n, sw3);
-		convlit(n->ntest, t);
-		prepsw(n);
+	/*
+	 * classify the switch test
+	 * Strue or Sfalse if the test is a bool constant
+	 *	this allows cases to be map/chan/interface assignments
+	 *	as well as (boolean) expressions
+	 * Stype if the test is v := interface.(type)
+	 *	this forces all cases to be types
+	 * Snorm otherwise
+	 *	all cases are expressions
+	 */
+	if(sw->ntest->op == OTYPESW) {
+		typeswitch(sw);
+		return;
 	}
+	arg = Snorm;
+	if(whatis(sw->ntest) == Wlitbool) {
+		arg = Strue;
+		if(sw->ntest->val.u.xval == 0)
+			arg = Sfalse;
+	}
+
+	/*
+	 * init statement is nothing important
+	 */
+	walktype(sw->ntest, Erv);
+//print("after walkwalks\n");
+
+	/*
+	 * pass 0,1,2,3
+	 * walk the cases as appropriate for switch type
+	 */
+	walkcases(sw, sw0, arg);
+	t = sw->ntest->type;
+	if(t == T)
+		t = walkcases(sw, sw1, arg);
+	if(t == T)
+		t = walkcases(sw, sw2, arg);
+	if(t == T)
+		return;
+	walkcases(sw, sw3, arg);
+	convlit(sw->ntest, t);
+//print("after walkcases\n");
+
+	/*
+	 * convert the switch into OIF statements
+	 */
+	prepsw(sw, arg);
+	walkstate(sw->nbody);
+//print("normal done\n");
 }

src/runtime/iface.c

@@ -315,7 +315,7 @@ sys·ifaceI2T2(Sigt *st, Iface i, ...)
 	ret = (byte*)(&i+1);
 	alg = st->hash & 0xFF;
 	wid = st->offset;
-	ok = (bool*)(ret+rnd(wid, 8));
+	ok = (bool*)(ret+rnd(wid, 1));
 
 	if(iface_debug) {
 		prints("I2T2 sigt=");