Implement VM modules and globals

1 files changed, 27 insertions, 3 deletions

diff --git a/pkg/lang/vm/errors.go b/pkg/lang/vm/errors.go
index bfc8a34..0dd73e7 100644
--- a/pkg/lang/vm/errors.go
+++ b/pkg/lang/vm/errors.go
@@ -9,16 +9,16 @@ import (
 )
 
 type Error struct {
-	Pc   int
+	Pos  code.Pos
 	Line int
 	Err  error
 }
 
 func (e Error) Error() string {
 	if e.Line == -1 {
-		return fmt.Sprintf("vm error at pc %d, unknown line: %v", e.Pc, e.Err)
+		return fmt.Sprintf("vm error in module '%d' at pc %d, unknown line: %v", e.Pos.Module, e.Pos.PC, e.Err)
 	}
-	return fmt.Sprintf("vm error at pc %d, line %d: %v", e.Pc, e.Line, e.Err)
+	return fmt.Sprintf("vm error in module '%d' at pc %d, line %d: %v", e.Pos.Module, e.Pos.PC, e.Line, e.Err)
 }
 
 // Fatal errors
@@ -111,3 +111,27 @@ type ErrWrongNumberOfArguments struct {
 func (e ErrWrongNumberOfArguments) Error() string {
 	return fmt.Sprintf("wrong number of arguments: needed %d, got %d", e.Needed, e.Got)
 }
+
+type ErrCantAddGlobalFromMain struct {
+	GlobalName string
+}
+
+func (e ErrCantAddGlobalFromMain) Error() string {
+	return fmt.Sprintf("can't export '%s' from main module", e.GlobalName)
+}
+
+type ErrGlobalAlreadyExists struct {
+	GlobalName string
+}
+
+func (e ErrGlobalAlreadyExists) Error() string {
+	return fmt.Sprintf("global '%s' already exists", e.GlobalName)
+}
+
+type ErrNoSuchGlobal struct {
+	GlobalName string
+}
+
+func (e ErrNoSuchGlobal) Error() string {
+	return fmt.Sprintf("no such global '%s'", e.GlobalName)
+}