Add index to transaction, stating its position inside the block.

ipld/ipldbindcode/ledger.ipldsch

@@ -70,6 +70,8 @@ type Transaction struct {
   metadata DataFrame
   # The slot number where this transaction was created.
   slot     Int
+  # The index of this transaction in the the block (0-indexed).
+  index nullable optional  Int
 } representation tuple
 
 type Hash bytes

ipld/ipldbindcode/methods.go

@@ -94,3 +94,17 @@ func VerifyHash(data []byte, hash int) error {
 	}
 	return nil
 }
+
+// Transaction.HasIndex returns whether the 'Index' field is present.
+func (n Transaction) HasIndex() bool {
+	return n.Index != nil && *n.Index != nil
+}
+
+// GetIndex returns the value of the 'Index' field and
+// a flag indicating whether the field has a value.
+func (n Transaction) GetIndex() (int, bool) {
+	if n.Index == nil || *n.Index == nil {
+		return 0, false
+	}
+	return **n.Index, true
+}

ipld/ipldbindcode/types.go

@@ -53,6 +53,7 @@ type Transaction struct {
 	Data     DataFrame
 	Metadata DataFrame
 	Slot     int
+	Index    **int
 }
 type DataFrame struct {
 	Kind  int

ledger.ipldsch

@@ -70,6 +70,8 @@ type Transaction struct {
   metadata DataFrame
   # The slot number where this transaction was created.
   slot     Int
+  # The index of this transaction in the the block (0-indexed).
+  index nullable optional  Int
 } representation tuple
 
 type Hash bytes