go: add step3_env

1 files changed, 12 insertions, 0 deletions

diff --git a/go/src/types/types.go b/go/src/types/types.go
index 9fcc78c..2eacaaf 100644
--- a/go/src/types/types.go
+++ b/go/src/types/types.go
@@ -1,5 +1,9 @@
 package types
 
+import (
+    "errors"
+)
+
 //type Error interface {
 //    error
 //}
@@ -43,6 +47,14 @@ func Vector_Q(obj MalType) bool {
     }
 }
 
+func GetSlice(seq MalType) ([]MalType, error) {
+    switch obj := seq.(type) {
+    case List:   return obj.Val, nil
+    case Vector: return obj.Val, nil
+    default: return nil, errors.New("GetSlice called on non-sequence")
+    }
+}
+
 // Hash Maps
 func Hash_Map_Q(obj MalType) bool {
     switch obj.(type) {