# Indexed collection are ordoned collections.
# The first item is 0. The last is `length'-1.
-interface IndexedCollectionRead[E]
+interface SequenceRead[E]
special MapRead[Int, E]
# Get the first item.
# Is equivalent with `self'[0].
# Indexed collection are ordoned collections.
# The first item is 0. The last is `length'-1.
-interface IndexedCollection[E]
-special IndexedCollectionRead[E]
+interface Sequence[E]
+special SequenceRead[E]
special Map[Int, E]
special SimpleCollection[E]
# Set the first item.