utf8: add InString routines for decoding in strings

reflect: add InterfaceValue.Get(), remove Empty
strconv: add Quote, CanBackquote
fmt:
	* %q go-quoted " string
	* %#q go-quoted ` string if possible, " string otherwise
	* %x hexadecimal string
	* anywhere a string is okay, *[]byte is okay
	* flags # 0 - + space
	* print value inside interface, not interface itself
	* tests

R=r
DELTA=756  (597 added, 121 deleted, 38 changed)
OCL=19888
CL=19916

4 files changed, 31 insertions, 5 deletions

diff --git a/src/lib/reflect/all_test.go b/src/lib/reflect/all_test.go
index 203413e552..a6ac1a7c79 100644
--- a/src/lib/reflect/all_test.go
+++ b/src/lib/reflect/all_test.go
@@ -283,3 +283,14 @@ export func TestAll(tt *testing.T) {	// TODO(r): wrap up better
 		println(a[i]);
 	}
 }
+
+export func TestInterfaceGet(t *testing.T) {
+	var inter struct { e interface{ } };
+	inter.e = 123.456;
+	v1 := reflect.NewValue(&inter);
+	v2 := v1.(reflect.PtrValue).Sub().(reflect.StructValue).Field(0);
+	assert(v2.Type().String(), "interface { }");
+	i2 := v2.(reflect.InterfaceValue).Get();
+	v3 := reflect.NewValue(i2);
+	assert(v3.Type().String(), "float");
+}
diff --git a/src/lib/reflect/cast_amd64.s b/src/lib/reflect/cast_amd64.s
index a1363718ca..d0e97a3c2c 100644
--- a/src/lib/reflect/cast_amd64.s
+++ b/src/lib/reflect/cast_amd64.s
@@ -181,3 +181,13 @@ TEXT reflect·PtrRuntimeArrayToAddr(SB),7,$-8
 	MOVQ	AX, 16(SP)
 	RET
 
+TEXT reflect·AddrToPtrInterface(SB),7,$-8
+	MOVQ	8(SP), AX
+	MOVQ	AX, 16(SP)
+	RET
+
+TEXT reflect·PtrInterfaceToAddr(SB),7,$-8
+	MOVQ	8(SP), AX
+	MOVQ	AX, 16(SP)
+	RET
+
diff --git a/src/lib/reflect/gencast.sh b/src/lib/reflect/gencast.sh
index af90d8df2f..afb60de1a4 100755
--- a/src/lib/reflect/gencast.sh
+++ b/src/lib/reflect/gencast.sh
@@ -38,4 +38,5 @@ Float80
 String
 Bool
 RuntimeArray
+Interface
 !
diff --git a/src/lib/reflect/value.go b/src/lib/reflect/value.go
index ef6ddce7ae..65d4b5ca97 100644
--- a/src/lib/reflect/value.go
+++ b/src/lib/reflect/value.go
@@ -36,14 +36,13 @@ func AddrToPtrString(Addr) *string
 func AddrToPtrBool(Addr) *bool
 func AddrToPtrRuntimeArray(Addr) *RuntimeArray
 func PtrRuntimeArrayToAddr(*RuntimeArray) Addr
-
-export type Empty interface {}	// TODO(r): Delete when no longer needed?
+func AddrToPtrInterface(Addr) *interface{}
 
 export type Value interface {
 	Kind()	int;
 	Type()	Type;
 	Addr()	Addr;
-	Interface()	Empty;
+	Interface()	interface {};
 }
 
 // Common fields and functionality for all values
@@ -66,7 +65,7 @@ func (c *Common) Addr() Addr {
 	return c.addr
 }
 
-func (c *Common) Interface() Empty {
+func (c *Common) Interface() interface {} {
 	return sys.unreflect(*AddrToPtrAddr(c.addr), c.typ.String());
 }
 
@@ -714,12 +713,17 @@ func StructCreator(typ Type, addr Addr) Value {
 export type InterfaceValue interface {
 	Kind()	int;
 	Type()	Type;
+	Get()	interface {};
 }
 
 type InterfaceValueStruct struct {
 	Common
 }
 
+func (v *InterfaceValueStruct) Get() interface{} {
+	return *AddrToPtrInterface(v.addr);
+}
+
 func InterfaceCreator(typ Type, addr Addr) Value {
 	return &InterfaceValueStruct{ Common{InterfaceKind, typ, addr} }
 }
@@ -824,7 +828,7 @@ export func NewOpenArrayValue(typ ArrayType, len, cap int) ArrayValue {
 	return NewValueAddr(typ, PtrRuntimeArrayToAddr(array));
 }
 
-export func NewValue(e Empty) Value {
+export func NewValue(e interface {}) Value {
 	value, typestring  := sys.reflect(e);
 	p, ok := typecache[typestring];
 	if !ok {