3 files changed, 29 insertions, 10 deletions

diff --git a/pkg/lang/vm/value/cells.go b/pkg/lang/vm/value/cells.go
index 5abb032..19ecfde 100644
--- a/pkg/lang/vm/value/cells.go
+++ b/pkg/lang/vm/value/cells.go
@@ -1,6 +1,9 @@
 package value
 
-import "jinx/pkg/lang/vm/mem"
+import (
+	"jinx/pkg/lang/vm/code"
+	"jinx/pkg/lang/vm/mem"
+)
 
 type ArrayCell []Value
 
@@ -55,7 +58,7 @@ func (t TypeCell) DropCell(m mem.Mem) {
 	typ := t.Get()
 	for _, f := range typ.Methods {
 		// Wrap data in a Value to drop it.
-		val := NewFunction(0, 0).WithData(f)
+		val := NewFunction(code.Pos{}, 0).WithData(f)
 		val.Drop(m)
 	}
 
@@ -101,3 +104,17 @@ func (e EnvCell) MatchingCellKind() mem.CellKind {
 func (e EnvCell) Get() Env {
 	return Env(e)
 }
+
+type GlobalCell Value
+
+func (g GlobalCell) DropCell(m mem.Mem) {
+	panic("global cell cannot be dropped")
+}
+
+func (g GlobalCell) MatchingCellKind() mem.CellKind {
+	return mem.CellKindGlobal
+}
+
+func (g GlobalCell) Get() Value {
+	return Value(g)
+}
diff --git a/pkg/lang/vm/value/data.go b/pkg/lang/vm/value/data.go
index 18e1b3d..6c3d762 100644
--- a/pkg/lang/vm/value/data.go
+++ b/pkg/lang/vm/value/data.go
@@ -2,6 +2,7 @@ package value
 
 import (
 	"fmt"
+	"jinx/pkg/lang/vm/code"
 	"jinx/pkg/lang/vm/mem"
 	"strconv"
 	"strings"
@@ -127,7 +128,7 @@ func (n NullData) String(_ mem.Mem) (string, error) {
 }
 
 type FunctionData struct {
-	pc     int
+	pos    code.Pos
 	args   uint
 	env    mem.Ptr
 	native NativeFunc
@@ -135,8 +136,8 @@ type FunctionData struct {
 
 type NativeFunc func([]Value) (Value, error)
 
-func (f FunctionData) Pc() int {
-	return f.pc
+func (f FunctionData) Pos() code.Pos {
+	return f.pos
 }
 
 func (f FunctionData) Args() uint {
@@ -152,18 +153,18 @@ func (f FunctionData) Native() NativeFunc {
 }
 
 func (f FunctionData) WithEnv(env mem.Ptr) FunctionData {
-	return FunctionData{pc: f.pc, args: f.args, env: env, native: f.native}
+	return FunctionData{pos: f.pos, args: f.args, env: env, native: f.native}
 }
 
 func (f FunctionData) WithArgs(args uint) FunctionData {
-	return FunctionData{pc: f.pc, args: args, env: f.env, native: f.native}
+	return FunctionData{pos: f.pos, args: args, env: f.env, native: f.native}
 }
 
 func (f FunctionData) String(_ mem.Mem) (string, error) {
 	if f.native != nil {
 		return fmt.Sprintf("<fn(%d) native>", f.args), nil
 	} else {
-		return fmt.Sprintf("<fn(%d) %d>", f.args, f.pc), nil
+		return fmt.Sprintf("<fn(%d) %d:%d>", f.args, f.pos.Module, f.pos.PC), nil
 	}
 }
 
diff --git a/pkg/lang/vm/value/value.go b/pkg/lang/vm/value/value.go
index 5dd5012..b051f04 100644
--- a/pkg/lang/vm/value/value.go
+++ b/pkg/lang/vm/value/value.go
@@ -1,6 +1,7 @@
 package value
 
 import (
+	"jinx/pkg/lang/vm/code"
 	"jinx/pkg/lang/vm/mem"
 )
 
@@ -52,8 +53,8 @@ func NewNull() Value {
 	return Value{t: CORE_TYPE_NULL, d: NullData{}}
 }
 
-func NewFunction(pc int, args uint) Value {
-	return Value{t: CORE_TYPE_FUNCTION, d: FunctionData{pc: pc, args: args}}
+func NewFunction(pos code.Pos, args uint) Value {
+	return Value{t: CORE_TYPE_FUNCTION, d: FunctionData{pos: pos, args: args}}
 }
 
 func NewNativeFunction(f NativeFunc, args uint) Value {