Hook up command history and populate it from IPython's history DB

IPython/terminal/ptshell.py

@@ -1,64 +1,76 b''
 from IPython.core.interactiveshell import InteractiveShell
 
+from prompt_toolkit.history import InMemoryHistory
 from prompt_toolkit.shortcuts import create_prompt_application
 from prompt_toolkit.interface import CommandLineInterface
 from prompt_toolkit.key_binding.manager import KeyBindingManager
 from prompt_toolkit.keys import Keys
 from prompt_toolkit.layout.lexers import PygmentsLexer
 
 from pygments.lexers import Python3Lexer
 from pygments.token import Token
 
 
 class PTInteractiveShell(InteractiveShell):
     pt_cli = None
 
     def get_prompt_tokens(self, cli):
         return [
             (Token.Prompt, 'In ['),
             (Token.Prompt, str(self.execution_count)),
             (Token.Prompt, ']: '),
         ]
 
 
     def init_prompt_toolkit_cli(self):
         kbmanager = KeyBindingManager.for_prompt()
         @kbmanager.registry.add_binding(Keys.ControlJ) # Ctrl+J == Enter, seemingly
         def _(event):
             b = event.current_buffer
             if not b.document.on_last_line:
                 b.newline()
                 return
 
             status, indent = self.input_splitter.check_complete(b.document.text)
 
             if (status != 'incomplete') and b.accept_action.is_returnable:
                 b.accept_action.validate_and_handle(event.cli, b)
             else:
-                b.insert_text('\n' + (' ' * indent))
+                b.insert_text('\n' + (' ' * (indent or 0)))
+
+        # Pre-populate history from IPython's history database
+        history = InMemoryHistory()
+        last_cell = u""
+        for _, _, cell in self.history_manager.get_tail(self.history_load_length,
+                                                        include_latest=True):
+            # Ignore blank lines and consecutive duplicates
+            cell = cell.rstrip()
+            if cell and (cell != last_cell):
+                history.append(cell)
 
         app = create_prompt_application(multiline=True,
                             lexer=PygmentsLexer(Python3Lexer),
                             get_prompt_tokens=self.get_prompt_tokens,
                             key_bindings_registry=kbmanager.registry,
+                            history=history,
         )
 
         self.pt_cli = CommandLineInterface(app)
 
     def __init__(self, *args, **kwargs):
         super(PTInteractiveShell, self).__init__(*args, **kwargs)
         self.init_prompt_toolkit_cli()
         self.keep_running = True
 
     def ask_exit(self):
         self.keep_running = False
 
     def interact(self):
         while self.keep_running:
             document = self.pt_cli.run()
             if document:
                 self.run_cell(document.text, store_history=True)
 
 
 if __name__ == '__main__':
     PTInteractiveShell().interact()