From 343f5aa7b4e11a8c0cb987fd7f7e9cbd66127c04 Mon Sep 17 00:00:00 2001
From: Ken Thompson <ken@golang.org>
Date: Thu, 12 Jun 2008 21:48:56 -0700
Subject: [PATCH] better import/export

SVN=122584
---
 src/cmd/gc/export.c | 20 +++++++++++++++++---
 src/cmd/gc/go.h     |  2 ++
 src/cmd/gc/go.y     | 17 +++++++++++++++--
 src/cmd/gc/lex.c    |  1 +
 src/cmd/gc/subr.c   |  2 +-
 test/float_lit.go   | 11 +++--------
 6 files changed, 39 insertions(+), 14 deletions(-)

diff --git a/src/cmd/gc/export.c b/src/cmd/gc/export.c
index b1ddfea6254..49048557700 100644
--- a/src/cmd/gc/export.c
+++ b/src/cmd/gc/export.c
@@ -14,11 +14,13 @@ markexport(Node *n)
 loop:
 	if(n == N)
 		return;
+
 	if(n->op == OLIST) {
 		markexport(n->left);
 		n = n->right;
 		goto loop;
 	}
+
 	if(n->op != OEXPORT)
 		fatal("markexport: op no OEXPORT: %O", n->op);
 
@@ -252,6 +254,8 @@ dumpexport(void)
 	Bprint(bout, "   import\n");
 	Bprint(bout, "   ((\n");
 
+	Bprint(bout, "    package %s\n", package);
+
 	// print it depth first
 	for(d=exportlist->forw; d!=D; d=d->forw) {
 		dynlineno = d->lineno;
@@ -266,6 +270,19 @@ dumpexport(void)
 /*
  * ******* import *******
  */
+void
+renamepkg(Node *n)
+{
+	if(n->psym == pkgimportname)
+		if(pkgmyname != S)
+			n->psym = pkgmyname;
+
+	if(n->psym->lexical != LPACK) {
+		warn("%S is becoming a package behind your back", n->psym);
+		n->psym->lexical = LPACK;
+	}
+}
+
 Sym*
 getimportsym(Node *ss)
 {
@@ -276,9 +293,6 @@ getimportsym(Node *ss)
 		fatal("getimportsym: oops1 %N\n", ss);
 
 	pkg = ss->psym->name;
-	if(pkgmyname != S)
-		pkg = pkgmyname->name;
-
 	s = pkglookup(ss->sym->name, pkg);
 
 	/* botch - need some diagnostic checking for the following assignment */
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 3ccefa84847..5c65a0139b9 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -333,6 +333,7 @@ EXTERN	Sym*	hash[NHASH];
 EXTERN	Sym*	dclstack;
 EXTERN	Sym*	b0stack;
 EXTERN	Sym*	pkgmyname;	// my name for package
+EXTERN	Sym*	pkgimportname;	// package name from imported package
 EXTERN	int	tptr;		// either TPTR32 or TPTR64
 extern	char*	sysimport;
 
@@ -498,6 +499,7 @@ Type*	forwdcl(Sym*);
 /*
  *	export.c
  */
+void	renamepkg(Node*);
 void	markexport(Node*);
 void	dumpe(Sym*);
 void	dumpexport(void);
diff --git a/src/cmd/gc/go.y b/src/cmd/gc/go.y
index ce7c89a810d..c2060630090 100644
--- a/src/cmd/gc/go.y
+++ b/src/cmd/gc/go.y
@@ -86,7 +86,7 @@ import:
 |	LIMPORT '(' import_stmt_list_r osemi ')'
 
 import_stmt:
-	import_here import_there
+	import_here import_package import_there
 
 import_here:
 	LLITERAL
@@ -109,6 +109,17 @@ import_here:
 		importfile(&$2);
 	}
 
+import_package:
+	LPACKAGE sym
+	{
+		pkgimportname = $2;
+
+		// if we are not remapping the package name
+		// then the imported package name is LPACK
+		if(pkgmyname == S)
+			pkgimportname->lexical = LPACK;
+	}
+
 import_there:
 	hidden_import_list_r ')' ')'
 	{
@@ -1330,11 +1341,11 @@ hidden_import:
 isym:
 	sym '.' sym
 	{
-		$1->lexical = LPACK;
 		$$ = nod(OIMPORT, N, N);
 		$$->osym = $1;
 		$$->psym = $1;
 		$$->sym = $3;
+		renamepkg($$);
 	}
 |	'(' sym ')' sym '.' sym
 	{
@@ -1342,6 +1353,7 @@ isym:
 		$$->osym = $2;
 		$$->psym = $4;
 		$$->sym = $6;
+		renamepkg($$);
 	}
 
 hidden_importsym:
@@ -1349,6 +1361,7 @@ hidden_importsym:
 |	'!' isym
 	{
 		$$ = $2;
+		$$->etype = 1;
 	}
 
 hidden_importfield:
diff --git a/src/cmd/gc/lex.c b/src/cmd/gc/lex.c
index 96380c647b2..03b7b859272 100644
--- a/src/cmd/gc/lex.c
+++ b/src/cmd/gc/lex.c
@@ -868,6 +868,7 @@ static	struct
 	"true",		LTRUE,		Txxx,
 	"type",		LTYPE,		Txxx,
 	"var",		LVAR,		Txxx,
+	"sys",		LPACK,		Txxx,
 
 	"notwithstanding",		LIGNORE,	Txxx,
 	"thetruthofthematter",		LIGNORE,	Txxx,
diff --git a/src/cmd/gc/subr.c b/src/cmd/gc/subr.c
index efbef36c43c..919589ac48d 100644
--- a/src/cmd/gc/subr.c
+++ b/src/cmd/gc/subr.c
@@ -871,7 +871,7 @@ Tconv(Fmt *fp)
 		break;
 
 	case TMAP:
-		snprint(buf, sizeof(buf), "[%T]%T", t->down, t->type);
+		snprint(buf, sizeof(buf), "MAP[%T]%T", t->down, t->type);
 		break;
 
 	case TARRAY:
diff --git a/test/float_lit.go b/test/float_lit.go
index b43ae58ccf5..e5e95e68eb4 100644
--- a/test/float_lit.go
+++ b/test/float_lit.go
@@ -18,7 +18,7 @@ func
 close(da double, ia, ib int64, pow int) bool
 {
 	db := double(ia) / double(ib);
-	db = db*pow10(pow);
+	db *= pow10(pow);
 
 	if da == 0 {
 		if db == 0 {
@@ -27,17 +27,12 @@ close(da double, ia, ib int64, pow int) bool
 		return false;
 	}
 
-	dd := da-db;
-	if dd < 0 {
-		dd = -dd;
-	}
-
-	de := da;
+	de := (da-db) /da;
 	if de < 0 {
 		de = -de;
 	}
 
-	if de*1.0e-14 > dd {
+	if de < 1.0e-14 {
 		return true;
 	}
 	return false;