values read themselves

ent/array.go

@@ -20,7 +20,7 @@ func arrayType(spec *typeSpec, env *Env) tÿpe {
 	elemSpec := *spec
 	elemSpec.typeName = elemName
 	elemType := parseTypeSpec(&elemSpec, env)
-	return array_t{elemType, count}
+	return &array_t{elemType, count}
 }
 
 func parseArrayName(s string) (string, int) {
@@ -49,18 +49,28 @@ type array_t struct {
 	count int
 }
 
+func (t *array_t) nü() value       { return array{t: t, slots: make([]value, t.count)} }
 func (t array_t) typeName() string { return fmt.Sprintf("array:%s", t.elem.typeName()) }
 
-func (t array_t) read(r bit.Reader) (value, error) {
-	var err error
-	v := make(array, t.count)
-	for i := range v {
-		v[i], err = t.elem.read(r)
-		if err != nil {
-			return nil, wrap(err, "array read error at index %d", i)
+type array struct {
+	t     *array_t
+	slots []value
+}
+
+func (a array) tÿpe() tÿpe { return a.t }
+
+func (a array) read(r bit.Reader) error {
+	for i := range a.slots {
+		if a.slots[i] == nil {
+			a.slots[i] = a.t.elem.nü()
+		}
+		if err := a.slots[i].read(r); err != nil {
+			return wrap(err, "array read error at index %d", i)
 		}
 	}
-	return v, r.Err()
+	return r.Err()
 }
 
-type array []value
+func (a array) String() string {
+	return fmt.Sprintf("%s%v", a.t.typeName(), a.slots)
+}

ent/atoms.go

@@ -1,75 +1,254 @@
 package ent
 
 import (
+	"fmt"
 	"github.com/jordanorelli/hyperstone/bit"
+	"strconv"
 )
 
-var atom_types = []typeLiteral{
-	{
-		"bool",
-		func(r bit.Reader) (value, error) {
-			return bit.ReadBool(r), r.Err()
-		},
+// ------------------------------------------------------------------------------
+// bool
+// ------------------------------------------------------------------------------
+
+var bool_t = &typeLiteral{
+	name: "bool",
+	newFn: func() value {
+		return new(bool_v)
 	},
-	{
-		"uint8",
-		func(r bit.Reader) (value, error) {
-			// TODO: bounds check here
-			return uint8(bit.ReadVarInt(r)), r.Err()
-		},
+}
+
+type bool_v bool
+
+func (v bool_v) tÿpe() tÿpe { return bool_t }
+
+func (v *bool_v) read(r bit.Reader) error {
+	*v = bool_v(bit.ReadBool(r))
+	return r.Err()
+}
+
+func (v bool_v) String() string {
+	if v {
+		return "true"
+	}
+	return "false"
+}
+
+// ------------------------------------------------------------------------------
+// uint8
+// ------------------------------------------------------------------------------
+
+var uint8_t = &typeLiteral{
+	name: "uint8",
+	newFn: func() value {
+		return new(uint8_v)
 	},
-	{
-		"uint16",
-		func(r bit.Reader) (value, error) {
-			// TODO: bounds check here
-			return uint16(bit.ReadVarInt(r)), r.Err()
-		},
+}
+
+type uint8_v uint8
+
+func (v uint8_v) tÿpe() tÿpe { return uint8_t }
+func (v *uint8_v) read(r bit.Reader) error {
+	u := bit.ReadVarInt(r)
+	if u > 1<<8-1 {
+		return fmt.Errorf("uint8 overflow: %d", u)
+	}
+	*v = uint8_v(u)
+	return r.Err()
+}
+
+func (v uint8_v) String() string {
+	return strconv.FormatUint(uint64(v), 10)
+}
+
+// ------------------------------------------------------------------------------
+// uint16
+// ------------------------------------------------------------------------------
+
+var uint16_t = &typeLiteral{
+	name: "uint16",
+	newFn: func() value {
+		return new(uint16_v)
 	},
-	{
-		"uint32",
-		func(r bit.Reader) (value, error) {
-			return bit.ReadVarInt32(r), r.Err()
-		},
+}
+
+type uint16_v uint16
+
+func (v uint16_v) tÿpe() tÿpe { return uint16_t }
+func (v *uint16_v) read(r bit.Reader) error {
+	u := bit.ReadVarInt(r)
+	if u > 1<<16-1 {
+		return fmt.Errorf("uint16 overflow: %d", u)
+	}
+	*v = uint16_v(u)
+	return r.Err()
+}
+
+func (v uint16_v) String() string {
+	return strconv.FormatUint(uint64(v), 10)
+}
+
+// ------------------------------------------------------------------------------
+// uint32
+// ------------------------------------------------------------------------------
+
+var uint32_t = &typeLiteral{
+	name: "uint32",
+	newFn: func() value {
+		return new(uint32_v)
 	},
-	{
-		"uint64",
-		func(r bit.Reader) (value, error) {
-			return bit.ReadVarInt(r), r.Err()
-		},
+}
+
+type uint32_v uint32
+
+func (v uint32_v) tÿpe() tÿpe { return uint32_t }
+func (v *uint32_v) read(r bit.Reader) error {
+	u := bit.ReadVarInt(r)
+	if u > 1<<32-1 {
+		return fmt.Errorf("uint32 overflow: %d", u)
+	}
+	*v = uint32_v(u)
+	return r.Err()
+}
+
+func (v uint32_v) String() string {
+	return strconv.FormatUint(uint64(v), 0)
+}
+
+// ------------------------------------------------------------------------------
+// uint64
+// ------------------------------------------------------------------------------
+
+var uint64_t = &typeLiteral{
+	name: "uint64",
+	newFn: func() value {
+		return new(uint64_v)
 	},
-	{
-		"int8",
-		func(r bit.Reader) (value, error) {
-			// TODO: bounds check here
-			return int8(bit.ReadZigZag32(r)), r.Err()
-		},
+}
+
+type uint64_v uint64
+
+func (v uint64_v) tÿpe() tÿpe { return uint64_t }
+func (v *uint64_v) read(r bit.Reader) error {
+	*v = uint64_v(bit.ReadVarInt(r))
+	return r.Err()
+}
+
+func (v uint64_v) String() string {
+	return strconv.FormatUint(uint64(v), 10)
+}
+
+// ------------------------------------------------------------------------------
+// int8
+// ------------------------------------------------------------------------------
+
+var int8_t = &typeLiteral{
+	name: "int8",
+	newFn: func() value {
+		return new(int8_v)
 	},
-	{
-		"int32",
-		func(r bit.Reader) (value, error) {
-			return bit.ReadZigZag32(r), r.Err()
-		},
+}
+
+type int8_v int8
+
+func (v int8_v) tÿpe() tÿpe { return int8_t }
+func (v *int8_v) read(r bit.Reader) error {
+	// TODO: bounds check here?
+	*v = int8_v(bit.ReadZigZag32(r))
+	return r.Err()
+}
+
+func (v int8_v) String() string {
+	return strconv.FormatInt(int64(v), 10)
+}
+
+// ------------------------------------------------------------------------------
+// int32
+// ------------------------------------------------------------------------------
+
+var int32_t = &typeLiteral{
+	name: "int32",
+	newFn: func() value {
+		return new(int32_v)
 	},
-	{
-		"CUtlStringToken",
-		func(r bit.Reader) (value, error) {
-			return bit.ReadVarInt(r), r.Err()
-		},
+}
+
+type int32_v int32
+
+func (v int32_v) tÿpe() tÿpe { return int32_t }
+func (v *int32_v) read(r bit.Reader) error {
+	*v = int32_v(bit.ReadZigZag32(r))
+	return r.Err()
+}
+
+func (v int32_v) String() string {
+	return strconv.FormatInt(int64(v), 10)
+}
+
+// ------------------------------------------------------------------------------
+// CUtlStringToken
+//
+// weirdly, this type isn't a string; it's actually a number. The number
+// presumably indicates some value on a symbol table.
+// ------------------------------------------------------------------------------
+
+var stringToken_t = &typeLiteral{
+	name: "CUtlStringToken",
+	newFn: func() value {
+		return new(stringToken_v)
 	},
-	{
-		"Color",
-		func(r bit.Reader) (value, error) {
-			u := bit.ReadVarInt(r)
-			return color{
-				r: uint8(u >> 6 & 0xff),
-				g: uint8(u >> 4 & 0xff),
-				b: uint8(u >> 2 & 0xff),
-				a: uint8(u >> 0 & 0xff),
-			}, r.Err()
-		},
+}
+
+type stringToken_v uint64
+
+func (v stringToken_v) tÿpe() tÿpe { return stringToken_t }
+func (v *stringToken_v) read(r bit.Reader) error {
+	*v = stringToken_v(bit.ReadVarInt(r))
+	return r.Err()
+}
+
+func (v stringToken_v) String() string {
+	return fmt.Sprintf("token:%d", v)
+}
+
+// ------------------------------------------------------------------------------
+// Color
+// ------------------------------------------------------------------------------
+
+var color_t = &typeLiteral{
+	name: "Color",
+	newFn: func() value {
+		return new(color)
 	},
 }
 
+type color struct{ r, g, b, a uint8 }
+
+func (c color) tÿpe() tÿpe { return color_t }
+func (c *color) read(r bit.Reader) error {
+	u := bit.ReadVarInt(r)
+	c.r = uint8(u >> 6 & 0xff)
+	c.g = uint8(u >> 4 & 0xff)
+	c.b = uint8(u >> 2 & 0xff)
+	c.a = uint8(u >> 0 & 0xff)
+	return r.Err()
+}
+
+func (c color) String() string {
+	return fmt.Sprintf("#%x%x%x%x", c.r, c.g, c.b, c.a)
+}
+
+var atom_types = []tÿpe{
+	bool_t,
+	uint8_t,
+	uint16_t,
+	uint32_t,
+	uint64_t,
+	int8_t,
+	int32_t,
+	stringToken_t,
+	color_t,
+}
+
 func atomType(spec *typeSpec, env *Env) tÿpe {
 	for _, t := range atom_types {
 		if t.typeName() == spec.typeName {
@@ -79,5 +258,3 @@ func atomType(spec *typeSpec, env *Env) tÿpe {
 	}
 	return nil
 }
-
-type color struct{ r, g, b, a uint8 }

ent/class.go

@@ -24,8 +24,8 @@ func (c *class) read(r bit.Reader) (value, error) {
 	return c.nü(), nil
 }
 
-func (c *class) nü() entity {
-	return entity{class: c, slots: make([]value, len(c.fields))}
+func (c *class) nü() value {
+	return &entity{class: c, slots: make([]value, len(c.fields))}
 }
 
 type classHistory struct {

ent/entity.go

@@ -1,6 +1,7 @@
 package ent
 
 import (
+	"fmt"
 	"github.com/jordanorelli/hyperstone/bit"
 )
 
@@ -31,6 +32,12 @@ func (e *entity) className() string {
 	return "<None>"
 }
 
+func (e *entity) String() string {
+	return fmt.Sprintf("%s{%v}", e.class.typeName(), e.slots)
+}
+
+func (e *entity) tÿpe() tÿpe                  { return e.class }
 func (e *entity) slotType(i int) tÿpe         { return e.class.fields[i].tÿpe }
+func (e *entity) slotName(i int) string       { return e.class.fields[i].name }
 func (e *entity) setSlotValue(i int, v value) { e.slots[i] = v }
 func (e *entity) getSlotValue(i int) value    { return e.slots[i] }

ent/float.go

@@ -2,6 +2,7 @@ package ent
 
 import (
 	"math"
+	"strconv"
 
 	"github.com/jordanorelli/hyperstone/bit"
 )
@@ -23,12 +24,7 @@ func floatType(spec *typeSpec, env *Env) tÿpe {
 	}
 	if spec.encoder == "coord" {
 		Debug.Printf("  coord float type")
-		return typeLiteral{
-			"float:coord",
-			func(r bit.Reader) (value, error) {
-				return bit.ReadCoord(r), r.Err()
-			},
-		}
+		return coord_t
 	}
 	if spec.serializer == "simulationtime" {
 		return nil
@@ -36,18 +32,50 @@ func floatType(spec *typeSpec, env *Env) tÿpe {
 	switch spec.bits {
 	case 0, 32:
 		Debug.Printf("  std float type")
-		return typeLiteral{
-			"float:std",
-			func(r bit.Reader) (value, error) {
-				// TODO: check uint32 overflow here?
-				return math.Float32frombits(uint32(r.ReadBits(32))), r.Err()
-			},
-		}
+		return float_t
 	default:
 		return qFloatType(spec, env)
 	}
 }
 
+var coord_t = &typeLiteral{
+	name: "coord",
+	newFn: func() value {
+		return new(coord_v)
+	},
+}
+
+type coord_v float32
+
+func (v coord_v) tÿpe() tÿpe { return coord_t }
+func (v *coord_v) read(r bit.Reader) error {
+	*v = coord_v(bit.ReadCoord(r))
+	return r.Err()
+}
+
+func (v coord_v) String() string {
+	return strconv.FormatFloat(float64(v), 'f', 3, 32)
+}
+
+var float_t = &typeLiteral{
+	name: "float",
+	newFn: func() value {
+		return new(float_v)
+	},
+}
+
+type float_v float32
+
+func (v float_v) tÿpe() tÿpe { return float_t }
+func (v *float_v) read(r bit.Reader) error {
+	*v = float_v(math.Float32frombits(uint32(r.ReadBits(32))))
+	return r.Err()
+}
+
+func (v float_v) String() string {
+	return strconv.FormatFloat(float64(v), 'f', 3, 32)
+}
+
 func qFloatType(spec *typeSpec, env *Env) tÿpe {
 	if spec.bits < 0 {
 		return typeError("quantized float has invalid negative bit count specifier")
@@ -56,7 +84,7 @@ func qFloatType(spec *typeSpec, env *Env) tÿpe {
 		return typeError("quantized float has invalid negative range")
 	}
 
-	t := qfloat_t{typeSpec: *spec}
+	t := &qfloat_t{typeSpec: *spec}
 	t.span = t.high - t.low
 	t.intervals = uint(1<<t.bits - 1)
 	t.interval = t.span / float32(t.intervals)
@@ -87,11 +115,24 @@ type qfloat_t struct {
 	special   *float32
 }
 
+func (t *qfloat_t) nü() value       { return &qfloat_v{t: t} }
 func (t qfloat_t) typeName() string { return "qfloat" }
 
-func (t qfloat_t) read(r bit.Reader) (value, error) {
-	if t.special != nil && bit.ReadBool(r) {
-		return *t.special, nil
+type qfloat_v struct {
+	t *qfloat_t
+	v float32
+}
+
+func (v qfloat_v) tÿpe() tÿpe { return v.t }
+func (v *qfloat_v) read(r bit.Reader) error {
+	if v.t.special != nil && bit.ReadBool(r) {
+		v.v = *v.t.special
+	} else {
+		v.v = v.t.low + float32(r.ReadBits(v.t.bits))*v.t.interval
 	}
-	return t.low + float32(r.ReadBits(t.bits))*t.interval, r.Err()
+	return r.Err()
+}
+
+func (v qfloat_v) String() string {
+	return strconv.FormatFloat(float64(v.v), 'f', 3, 32)
 }

ent/generic.go

@@ -24,14 +24,10 @@ func genericType(spec *typeSpec, env *Env) tÿpe {
 
 	switch genericName {
 	case "CHandle", "CStrongHandle":
-		return typeLiteral{
-			fmt.Sprintf("handle:%s", genericName),
-			func(r bit.Reader) (value, error) {
-				return handle(bit.ReadVarInt(r)), r.Err()
-			},
-		}
+		t := handle_t(spec.typeName)
+		return &t
 	case "CUtlVector":
-		return cutl_vector_t{elem}
+		return &cutl_vector_t{elem}
 	default:
 		return typeError("unknown generic name: %v", parts[0])
 	}
@@ -75,11 +71,27 @@ type cutl_vector_t struct {
 	elem tÿpe
 }
 
+func (t *cutl_vector_t) nü() value {
+	return &cutl_vector{t: t}
+}
+
 func (t cutl_vector_t) typeName() string {
 	return fmt.Sprintf("vector:%s", t.elem.typeName())
 }
 
-func (t cutl_vector_t) read(r bit.Reader) (value, error) {
+type cutl_vector struct {
+	t     tÿpe
+	slots []value
+}
+
+func (v *cutl_vector) tÿpe() tÿpe { return v.t }
+
+func (v *cutl_vector) read(r bit.Reader) error {
 	count := bit.ReadVarInt32(r)
-	return make(array, count), r.Err()
+	v.slots = make([]value, count)
+	return r.Err()
+}
+
+func (v cutl_vector) String() string {
+	return fmt.Sprintf("%s<%v>", v.t.typeName(), v.slots)
 }

ent/handle.go

@@ -1,12 +1,32 @@
 package ent
 
 import (
+	"fmt"
+
 	"github.com/jordanorelli/hyperstone/bit"
 )
 
+type handle_t string
+
+func (t handle_t) typeName() string { return string(t) }
+func (t *handle_t) nü() value       { return &handle{t: t} }
+
 // a handle represents a soft pointer to an entity. handles are represented by
 // IDs and can cross the client-server divide.
-type handle int
+type handle struct {
+	t  tÿpe
+	id uint64
+}
+
+func (h handle) tÿpe() tÿpe { return h.t }
+func (h *handle) read(r bit.Reader) error {
+	h.id = bit.ReadVarInt(r)
+	return r.Err()
+}
+
+func (h handle) String() string {
+	return fmt.Sprintf("handle<%s>: %d", h.t.typeName(), h.id)
+}
 
 func handleType(spec *typeSpec, env *Env) tÿpe {
 	if spec.typeName != "CGameSceneNodeHandle" {
@@ -14,10 +34,6 @@ func handleType(spec *typeSpec, env *Env) tÿpe {
 	}
 
 	Debug.Printf("  handle type")
-	return typeLiteral{
-		"handle:CGameSceneNodeHandle",
-		func(r bit.Reader) (value, error) {
-			return handle(bit.ReadVarInt(r)), r.Err()
-		},
-	}
+	t := handle_t(spec.typeName)
+	return &t
 }

ent/hseq.go

@@ -1,19 +1,34 @@
 package ent
 
 import (
+	"fmt"
+
 	"github.com/jordanorelli/hyperstone/bit"
 )
 
+var hseq_t = &typeLiteral{
+	name: "HSequence",
+	newFn: func() value {
+		return new(hseq_v)
+	},
+}
+
+type hseq_v uint64
+
+func (v hseq_v) tÿpe() tÿpe { return hseq_t }
+func (v *hseq_v) read(r bit.Reader) error {
+	*v = hseq_v(bit.ReadVarInt(r) - 1)
+	return r.Err()
+}
+
+func (v hseq_v) String() string {
+	return fmt.Sprintf("hseq:%d", uint64(v))
+}
+
 func hSeqType(spec *typeSpec, env *Env) tÿpe {
 	if spec.typeName != "HSequence" {
 		return nil
 	}
-
 	Debug.Printf("  hsequence type")
-	return typeLiteral{
-		"HSequence",
-		func(r bit.Reader) (value, error) {
-			return bit.ReadVarInt(r) - 1, r.Err()
-		},
-	}
+	return hseq_t
 }

ent/qangle.go

@@ -1,12 +1,40 @@
 package ent
 
 import (
-	"github.com/jordanorelli/hyperstone/bit"
+	"fmt"
 	"math"
+
+	"github.com/jordanorelli/hyperstone/bit"
 )
 
+var qangle_t = &typeLiteral{
+	name: "qangle",
+	newFn: func() value {
+		return new(qangle)
+	},
+}
+
 type qangle struct{ pitch, yaw, roll float32 }
 
+func (q qangle) tÿpe() tÿpe { return qangle_t }
+func (q *qangle) read(r bit.Reader) error {
+	pitch, yaw, roll := bit.ReadBool(r), bit.ReadBool(r), bit.ReadBool(r)
+	if pitch {
+		q.pitch = bit.ReadCoord(r)
+	}
+	if yaw {
+		q.yaw = bit.ReadCoord(r)
+	}
+	if roll {
+		q.roll = bit.ReadCoord(r)
+	}
+	return r.Err()
+}
+
+func (q qangle) String() string {
+	return fmt.Sprintf("qangle{%f %f %f}", q.pitch, q.yaw, q.roll)
+}
+
 func qAngleType(spec *typeSpec, env *Env) tÿpe {
 	if spec.typeName != "QAngle" {
 		return nil
@@ -16,31 +44,16 @@ func qAngleType(spec *typeSpec, env *Env) tÿpe {
 		case spec.bits <= 0 || spec.bits > 32:
 			return typeError("qangle pitch_yaw has invalid bit size: %d", spec.bits)
 		case spec.bits == 32:
-			return typeLiteral{"qangle:pitchYaw", pitchYaw_t}
+			return pitchYaw_t
 		default:
-			return pitchYawAngles_t(spec.bits)
+			t := pitchYawAngles_t(spec.bits)
+			return &t
 		}
 	}
 	switch spec.bits {
 	case 0:
 		Debug.Printf("  qangle type")
-		return typeLiteral{
-			"qangle",
-			func(r bit.Reader) (value, error) {
-				var q qangle
-				pitch, yaw, roll := bit.ReadBool(r), bit.ReadBool(r), bit.ReadBool(r)
-				if pitch {
-					q.pitch = bit.ReadCoord(r)
-				}
-				if yaw {
-					q.yaw = bit.ReadCoord(r)
-				}
-				if roll {
-					q.roll = bit.ReadCoord(r)
-				}
-				return q, nil
-			},
-		}
+		return qangle_t
 	case 32:
 		return nil
 	default:
@@ -48,20 +61,45 @@ func qAngleType(spec *typeSpec, env *Env) tÿpe {
 	}
 }
 
-func pitchYaw_t(r bit.Reader) (value, error) {
-	var q qangle
-	q.pitch = math.Float32frombits(uint32(r.ReadBits(32)))
-	q.yaw = math.Float32frombits(uint32(r.ReadBits(32)))
-	return q, r.Err()
+var pitchYaw_t = &typeLiteral{
+	name: "qangle:pitchYaw",
+	newFn: func() value {
+		return new(pitchYaw_v)
+	},
+}
+
+type pitchYaw_v qangle
+
+func (v pitchYaw_v) tÿpe() tÿpe { return pitchYaw_t }
+func (v *pitchYaw_v) read(r bit.Reader) error {
+	v.pitch = math.Float32frombits(uint32(r.ReadBits(32)))
+	v.yaw = math.Float32frombits(uint32(r.ReadBits(32)))
+	return r.Err()
+}
+
+func (v pitchYaw_v) String() string {
+	return fmt.Sprintf("qangle:pitchYaw{%f %f}", v.pitch, v.yaw)
 }
 
 type pitchYawAngles_t uint
 
 func (t pitchYawAngles_t) typeName() string { return "qangle:pitchYawAngles" }
+func (t *pitchYawAngles_t) nü() value {
+	return &pitchYawAngles_v{t: t}
+}
+
+type pitchYawAngles_v struct {
+	t *pitchYawAngles_t
+	qangle
+}
+
+func (v pitchYawAngles_v) tÿpe() tÿpe { return v.t }
+func (v *pitchYawAngles_v) read(r bit.Reader) error {
+	v.pitch = bit.ReadAngle(r, uint(*v.t))
+	v.yaw = bit.ReadAngle(r, uint(*v.t))
+	return r.Err()
+}
 
-func (t pitchYawAngles_t) read(r bit.Reader) (value, error) {
-	var q qangle
-	q.pitch = bit.ReadAngle(r, uint(t))
-	q.yaw = bit.ReadAngle(r, uint(t))
-	return q, r.Err()
+func (v pitchYawAngles_v) String() string {
+	return fmt.Sprintf("qangle:pitchYawAngles{%f %f}", v.pitch, v.yaw)
 }

ent/selection.go

@@ -20,31 +20,35 @@ func (s selection) String() string { return fmt.Sprint(s.path()) }
 func (s selection) path() []int    { return s.vals[:s.count] }
 
 func (s selection) fillSlots(v slotted, r bit.Reader) error {
-	Debug.Printf("%v fill slots into %v", s, v)
-	return s.fillSlotsIter(0, v, r)
+	return s.fillSlotsIter(0, v, v.tÿpe().typeName(), r)
 }
 
-func (s selection) fillSlotsIter(offset int, dest slotted, r bit.Reader) error {
+func (s selection) fillSlotsIter(offset int, dest slotted, path string, r bit.Reader) error {
 	slot := s.vals[offset]
 	if s.count-offset <= 0 {
 		return fmt.Errorf("unable to fill selection %v having count %d at offset %d", s, s.count, offset)
 	}
 	switch s.count - offset {
 	case 1:
-		t := dest.slotType(slot)
-		v, err := t.read(r)
-		if err != nil {
+		v := dest.slotType(slot).nü()
+		if err := v.read(r); err != nil {
 			return fmt.Errorf("unable to fill selection: %v", err)
 		}
+		old := dest.getSlotValue(slot)
 		dest.setSlotValue(slot, v)
+		Debug.Printf("%v %s.%s (%s) %v -> %v", s, path, dest.slotName(slot), dest.slotType(slot).typeName(), old, v)
 		return nil
 	default:
 		v := dest.getSlotValue(slot)
+		if v == nil {
+			v = dest.slotType(slot).nü()
+			dest.setSlotValue(slot, v)
+		}
 		vs, ok := v.(slotted)
 		if !ok {
-			return fmt.Errorf("destination is not slotted")
+			return fmt.Errorf("dest isn't slotted")
 		}
-		return s.fillSlotsIter(offset+1, vs, r)
+		return s.fillSlotsIter(offset+1, vs, fmt.Sprintf("%s.%s", path, dest.slotName(slot)), r)
 	}
 }
 

ent/slotted.go

@@ -1,7 +1,9 @@
 package ent
 
 type slotted interface {
+	value
 	slotType(int) tÿpe
+	slotName(int) string
 	setSlotValue(int, value)
 	getSlotValue(int) value
 }

ent/type.go

@@ -8,17 +8,17 @@ import (
 )
 
 type tÿpe interface {
-	read(bit.Reader) (value, error)
+	nü() value
 	typeName() string
 }
 
 type typeLiteral struct {
-	name   string
-	readFn func(r bit.Reader) (value, error)
+	name  string
+	newFn func() value
 }
 
-func (t typeLiteral) typeName() string                 { return t.name }
-func (t typeLiteral) read(r bit.Reader) (value, error) { return t.readFn(r) }
+func (t typeLiteral) nü() value        { return t.newFn() }
+func (t typeLiteral) typeName() string { return t.name }
 
 type typeParseFn func(*typeSpec, *Env) tÿpe
 
@@ -42,14 +42,32 @@ func parseTypeSpec(spec *typeSpec, env *Env) tÿpe {
 		hSeqType, genericType, vectorType, classType, unknownType)
 }
 
+type unknown_t string
+
+func (t unknown_t) typeName() string { return string(t) }
+func (t *unknown_t) nü() value {
+	return &unknown_v{t: t}
+}
+
+type unknown_v struct {
+	t tÿpe
+	v uint64
+}
+
+func (v unknown_v) tÿpe() tÿpe { return v.t }
+func (v *unknown_v) read(r bit.Reader) error {
+	v.v = bit.ReadVarInt(r)
+	return r.Err()
+}
+
+func (v unknown_v) String() string {
+	return fmt.Sprintf("%s(unknown):%d", v.t.typeName(), v.v)
+}
+
 func unknownType(spec *typeSpec, env *Env) tÿpe {
 	Debug.Printf("Unknown Type: %v", spec)
-	return typeLiteral{
-		name: fmt.Sprintf("unknown:%s", spec.typeName),
-		readFn: func(r bit.Reader) (value, error) {
-			return bit.ReadVarInt(r), r.Err()
-		},
-	}
+	t := unknown_t(spec.typeName)
+	return &t
 }
 
 // a type error is both an error and a type. It represents a type that we were
@@ -62,11 +80,9 @@ func typeError(t string, args ...interface{}) tÿpe {
 
 type error_t string
 
+func (e error_t) nü() value        { panic("can't create an error val like that") }
 func (e error_t) typeName() string { return "error" }
 func (e error_t) Error() string    { return string(e) }
-func (e error_t) read(r bit.Reader) (value, error) {
-	return nil, fmt.Errorf("type error: %s", string(e))
-}
 
 type typeSpec struct {
 	name        string

ent/value.go

@@ -1,3 +1,11 @@
 package ent
 
-type value interface{}
+import (
+	"github.com/jordanorelli/hyperstone/bit"
+)
+
+type value interface {
+	String() string
+	tÿpe() tÿpe
+	read(bit.Reader) error
+}

ent/vector.go

@@ -5,8 +5,6 @@ import (
 	"github.com/jordanorelli/hyperstone/bit"
 )
 
-type vector struct{ x, y, z float32 }
-
 func vectorType(spec *typeSpec, env *Env) tÿpe {
 	if spec.encoder != "" {
 		return nil
@@ -18,7 +16,7 @@ func vectorType(spec *typeSpec, env *Env) tÿpe {
 	if t == nil {
 		return nil
 	}
-	return vector_t{elem: t}
+	return &vector_t{elem: t}
 }
 
 type vector_t struct {
@@ -29,19 +27,41 @@ func (t vector_t) typeName() string {
 	return fmt.Sprintf("vector:%s", t.elem.typeName())
 }
 
-func (t vector_t) read(r bit.Reader) (value, error) {
-	var err error
-	var v interface{}
-	read := func(f *float32) {
-		if err != nil {
-			return
+func (t *vector_t) nü() value {
+	return &vector{t: t}
+}
+
+type vector struct {
+	t       tÿpe
+	x, y, z value
+}
+
+func (v vector) tÿpe() tÿpe { return v.t }
+
+func (v *vector) read(r bit.Reader) error {
+	if v.x == nil {
+		v.x = v.t.nü()
+	}
+	if v.y == nil {
+		v.y = v.t.nü()
+	}
+	if v.z == nil {
+		v.z = v.t.nü()
+	}
+
+	type fn func(bit.Reader) error
+	coalesce := func(fns ...fn) error {
+		for _, f := range fns {
+			if err := f(r); err != nil {
+				return err
+			}
 		}
-		v, err = t.elem.read(r)
-		*f = v.(float32)
+		return nil
 	}
-	var out vector
-	read(&out.x)
-	read(&out.y)
-	read(&out.z)
-	return out, err
+
+	return coalesce(v.x.read, v.y.read, v.z.read)
+}
+
+func (v vector) String() string {
+	return fmt.Sprintf("vector<%s>{%s %s %s}", v.t.typeName, v.x, v.y, v.z)
 }