Initial code for new InteractiveShell subclass using prompt_toolkit

IPython/terminal/ptshell.py

@@ -0,0 +1,64 b''
+from IPython.core.interactiveshell import InteractiveShell
+
+from prompt_toolkit.buffer import Buffer
+from prompt_toolkit.shortcuts import create_prompt_layout
+from prompt_toolkit.filters import Condition
+from prompt_toolkit.interface import AcceptAction, Application, CommandLineInterface
+from prompt_toolkit.layout.lexers import PygmentsLexer
+
+from pygments.lexers import Python3Lexer
+from pygments.token import Token
+
+
+class PTInteractiveShell(InteractiveShell):
+    def _multiline(self, cli):
+        doc = cli.current_buffer.document
+        if not doc.on_last_line:
+            cli.run_in_terminal(lambda: print('Not on last line'))
+            return False
+        status, indent = self.input_splitter.check_complete(doc.text)
+        return status == 'incomplete'
+
+    def _multiline2(self):
+        return self._multiline(self.pt_cli)
+
+    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):
+        layout = create_prompt_layout(
+            get_prompt_tokens=self.get_prompt_tokens,
+            lexer=PygmentsLexer(Python3Lexer),
+            multiline=Condition(self._multiline),
+        )
+        buffer = Buffer(
+            is_multiline=Condition(self._multiline2),
+            accept_action=AcceptAction.RETURN_DOCUMENT,
+        )
+        app = Application(layout=layout, buffer=buffer)
+        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)
+
+
+if __name__ == '__main__':
+    PTInteractiveShell().interact()