Add support for multiline command

awsshell/app.py

@@ -12,7 +12,7 @@
 from prompt_toolkit.document import Document
 from prompt_toolkit.shortcuts import create_eventloop
 from prompt_toolkit.buffer import Buffer
-from prompt_toolkit.filters import Always
+from prompt_toolkit.filters import Always, Condition
 from prompt_toolkit.interface import CommandLineInterface, Application
 from prompt_toolkit.interface import AbortAction, AcceptAction
 from prompt_toolkit.auto_suggest import AutoSuggestFromHistory
@@ -344,14 +344,20 @@ def create_layout(self, display_completions_in_columns, toolbar):
             get_bottom_toolbar_tokens=toolbar.handler)
 
     def create_buffer(self, completer, history):
-        return Buffer(
+        def is_buffer_multiline():
+            return buffer.document.text.endswith('\\')
+
+        buffer = Buffer(
             history=history,
             auto_suggest=AutoSuggestFromHistory(),
             enable_history_search=True,
             completer=completer,
             complete_while_typing=Always(),
+            is_multiline=Condition(is_buffer_multiline),
             accept_action=AcceptAction.RETURN_DOCUMENT)
 
+        return buffer
+
     def create_key_manager(self):
         """Create the :class:`KeyManager`.