Extract stack package and hide behind interface

1 files changed, 34 insertions, 0 deletions

diff --git a/pkg/lang/vm/stack/errors.go b/pkg/lang/vm/stack/errors.go
new file mode 100644
index 0000000..55ef2ea
--- /dev/null
+++ b/pkg/lang/vm/stack/errors.go
@@ -0,0 +1,34 @@
+package stack
+
+import (
+	"errors"
+	"fmt"
+)
+
+var (
+	ErrStackOverflow  = errors.New("stack overflow (max depth: 1000)")
+	ErrStackUnderflow = errors.New("local stack underflow")
+
+	ErrReachedMaxCallDepth  = errors.New("reached max call depth (max depth: 1000)")
+	ErrReachedRootCallFrame = errors.New("reached root call frame")
+
+	ErrCallBaseCantBeNegative = errors.New("call base cannot be negative")
+)
+
+type ErrLocalIndexOutOfBounds struct {
+	Index int
+	Len   int
+}
+
+func (e ErrLocalIndexOutOfBounds) Error() string {
+	return fmt.Sprintf("local index out of bounds: %d (len: %d)", e.Index, e.Len)
+}
+
+type ErrStackIndexOutOfBounds struct {
+	Index int
+	Len   int
+}
+
+func (e ErrStackIndexOutOfBounds) Error() string {
+	return fmt.Sprintf("stack index out of bounds: %d (len: %d)", e.Index, e.Len)
+}