From: Ken Thompson <ken@golang.org>
Date: Wed, 22 Oct 2008 03:55:40 +0000 (-0700)
Subject: elided dots
X-Git-Tag: weekly.2009-11-06~2922
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=14c639161af6b7105a67541964fe6eaeb253d053;p=gostls13.git

elided dots

R=r
OCL=17601
CL=17601
---

diff --git a/src/cmd/gc/dcl.c b/src/cmd/gc/dcl.c
index 94a0646e4f..9a4fe73036 100644
--- a/src/cmd/gc/dcl.c
+++ b/src/cmd/gc/dcl.c
@@ -471,7 +471,7 @@ loop:
 
 	if(n->left != N && n->left->op == ONAME) {
 		f->nname = n->left;
-		f->imbedded = n->imbedded;
+		f->embedded = n->embedded;
 	} else {
 		vargen++;
 		snprint(buf, sizeof(buf), "_e%s_%.3ld", filename, vargen);
@@ -1150,17 +1150,17 @@ resumecheckwidth(void)
 }
 
 Node*
-imbedded(Sym *s)
+embedded(Sym *s)
 {
 	Node *n;
 
 	n = newname(lookup(s->name));
 	n = nod(ODCLFIELD, n, N);
-	n->imbedded = 1;
+	n->embedded = 1;
 	if(s == S)
 		return n;
 	n->type = oldtype(s);
 	if(isptr[n->type->etype])
-		yyerror("imbedded type cannot be a pointer");
+		yyerror("embedded type cannot be a pointer");
 	return n;
 }
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 4e1c0c5d98..973b6f2c63 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -124,7 +124,7 @@ struct	Type
 	uchar	trecur;		// to detect loops
 	uchar	methptr;	// 1=direct 2=pointer
 	uchar	printed;
-	uchar	imbedded;	// TFIELD imbedded type
+	uchar	embedded;	// TFIELD embedded type
 
 	// TFUNCT
 	uchar	thistuple;
@@ -163,7 +163,7 @@ struct	Node
 	uchar	class;		// PPARAM, PAUTO, PEXTERN, PSTATIC
 	uchar	method;		// OCALLMETH name
 	uchar	iota;		// OLITERAL made from iota
-	uchar	imbedded;	// ODCLFIELD imbedded type
+	uchar	embedded;	// ODCLFIELD embedded type
 
 	// most nodes
 	Node*	left;
@@ -673,7 +673,7 @@ void	checkarglist(Node*);
 void	checkwidth(Type*);
 void	defercheckwidth(void);
 void	resumecheckwidth(void);
-Node*	imbedded(Sym*);
+Node*	embedded(Sym*);
 
 /*
  *	export.c
@@ -714,7 +714,6 @@ void	walkstate(Node*);
 void	walktype(Node*, int);
 void	walkas(Node*);
 void	walkbool(Node*);
-void	adddot(Node*);
 Type*	walkswitch(Node*, Type*(*)(Node*, Type*));
 int	casebody(Node*);
 void	walkselect(Node*);
@@ -747,6 +746,7 @@ Node*	arraylit(Node*);
 Node*	maplit(Node*);
 Node*	selectas(Node*, Node*);
 Node*	old2new(Node*, Type*);
+Node*	adddot(Node*);
 
 /*
  *	const.c
diff --git a/src/cmd/gc/go.y b/src/cmd/gc/go.y
index fd0c5b48dc..352d60c9fd 100644
--- a/src/cmd/gc/go.y
+++ b/src/cmd/gc/go.y
@@ -58,7 +58,7 @@
 %type	<node>		name onew_name new_name new_name_list_r
 %type	<node>		vardcl_list_r vardcl Avardcl Bvardcl
 %type	<node>		interfacedcl_list_r interfacedcl
-%type	<node>		structdcl_list_r structdcl imbed
+%type	<node>		structdcl_list_r structdcl embed
 %type	<node>		fnres Afnres Bfnres fnliteral xfndcl fndcl fnbody
 %type	<node>		keyexpr_list braced_keyexpr_list keyval_list_r keyval
 
@@ -820,7 +820,7 @@ pexpr:
 |	pexpr '.' sym2
 	{
 		$$ = nod(ODOT, $1, newname($3));
-		adddot($$);
+		$$ = adddot($$);
 	}
 |	pexpr '.' '(' type ')'
 	{
@@ -1375,21 +1375,21 @@ structdcl:
 		$$ = nod(ODCLFIELD, $1, N);
 		$$->type = $2;
 	}
-|	imbed
-|	'*' imbed
+|	embed
+|	'*' embed
 	{
 		$$ = $2;
 		$$->type = ptrto($$->type);
 	}
 
-imbed:
+embed:
 	LATYPE
 	{
-		$$ = imbedded($1);
+		$$ = embedded($1);
 	}
 |	lpack '.' LATYPE
 	{
-		$$ = imbedded($3);
+		$$ = embedded($3);
 		context = nil;
 	}
 
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index c78ac1ab7b..6c991c6a6a 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -1507,13 +1507,13 @@ void
 walkdot(Node *n)
 {
 	Type *t, *f;
+	int d;
 
 	if(n->left == N || n->right == N)
 		return;
 	switch(n->op) {
 	case ODOTINTER:
 	case ODOTMETH:
-	case ODOTPTR:
 		return;	// already done
 	}
 
@@ -1539,29 +1539,6 @@ walkdot(Node *n)
 		yyerror("undefined DOT %S on %T", n->right->sym, n->left->type);
 }
 
-int
-adddot1(Node *n, int d)
-{
-	return 1;
-}
-
-void
-adddot(Node *n)
-{
-	int d;
-
-	walktype(n->left, Erv);
-	if(n->left->type == T)
-		return;
-	if(n->right->op != ONAME)
-		return;
-
-	for(d=0; d<5; d++)
-		if(adddot1(n, d))
-			break;
-//	dump("adddot", n);
-}
-
 Node*
 ascompatee(int op, Node **nl, Node **nr)
 {
@@ -3244,3 +3221,96 @@ loop:
 	r = listnext(&saver);
 	goto loop;
 }
+
+int
+lookdot0(Sym *s, Type *t)
+{
+	Type *f, *u;
+	int c;
+
+	u = t;
+	if(isptr[u->etype])
+		u = u->type;
+
+	c = 0;
+	if(u->etype == TSTRUCT || u->etype == TINTER) {
+		for(f=u->type; f!=T; f=f->down)
+			if(f->sym == s)
+				c++;
+	}
+//BOTCH need method
+	return c;
+}
+
+static	Node*	dotlist;
+
+int
+adddot1(Sym *s, Type *t, int d)
+{
+	Type *f, *u;
+	int c, a;
+
+	if(d == 0)
+		return lookdot0(s, t);
+
+	u = t;
+	if(isptr[u->etype])
+		u = u->type;
+	if(u->etype != TSTRUCT && u->etype != TINTER)
+		return 0;
+
+	c = 0;
+	for(f=u->type; f!=T; f=f->down) {
+		if(!f->embedded)
+			continue;
+		if(f->sym == S)
+			continue;
+		a = adddot1(s, f->type, d-1);
+		if(a != 0 && c == 0) {
+			dotlist = nod(ODOT, dotlist, N);
+			dotlist->type = f;
+		}
+		c += a;
+	}
+	return c;
+}
+
+Node*
+adddot(Node *n)
+{
+	Type *t;
+	Sym *s;
+	Node *l;
+	int c, d;
+
+	walktype(n->left, Erv);
+	t = n->left->type;
+	if(t == T)
+		return n;
+
+	if(n->right->op != ONAME)
+		return n;
+	s = n->right->sym;
+	if(s == S)
+		return n;
+
+	dotlist = N;
+	for(d=0; d<5; d++) {
+		c = adddot1(s, t, d);
+		if(c > 0)
+			goto out;
+	}
+	return n;
+
+out:
+	if(c > 1)
+		yyerror("ambiguous DOT reference %S", s);
+
+	// rebuild elided dots
+	for(l=dotlist; l!=N; l=l->left) {
+		n = nod(ODOT, n, n->right);
+		n->left->right = newname(l->type->sym);
+	}
+
+	return n;
+}