Handle errors gracefully in VM

1 files changed, 58 insertions, 0 deletions

diff --git a/pkg/lang/vm/errors.go b/pkg/lang/vm/errors.go
new file mode 100644
index 0000000..d19604a
--- /dev/null
+++ b/pkg/lang/vm/errors.go
@@ -0,0 +1,58 @@
+package vm
+
+import (
+	"errors"
+	"fmt"
+	"jinx/pkg/lang/vm/code"
+	"jinx/pkg/lang/vm/text"
+	"jinx/pkg/lang/vm/value"
+)
+
+// Fatal errors
+
+var (
+	ErrCallStackOverflow   = errors.New("call stack overflow (max depth: 1000)")
+	ErrLocalStackOverflow  = errors.New("local stack overflow (max depth: 1000)")
+	ErrNoPreviousCallFrame = errors.New("no previous call frame")
+	ErrCantPopRootFrame    = errors.New("cannot pop root frame")
+
+	ErrCallFrameEmpty = errors.New("current call frame is empty")
+)
+
+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 ErrInvalidOp struct {
+	Op uint8
+}
+
+func (e ErrInvalidOp) Error() string {
+	return fmt.Sprintf("invalid opcode: %d", e.Op)
+}
+
+// Non-fatal errors, which will later be implemented as catchable exceptions
+
+type ErrInvalidOperandTypes struct {
+	Op code.Op
+	X  value.Type
+	Y  value.Type
+}
+
+func (e ErrInvalidOperandTypes) Error() string {
+	return fmt.Sprintf("invalid operand types for op %s: %v, %v", text.OpToString(e.Op), e.X, e.Y)
+}
+
+type ErrArrayIndexOutOfBounds struct {
+	Index int
+	Len   int
+}
+
+func (e ErrArrayIndexOutOfBounds) Error() string {
+	return fmt.Sprintf("array index out of bounds: %d (len: %d)", e.Index, e.Len)
+}