Merge pull request #12570 from mskar/auto_suggest

IPython/terminal/interactiveshell.py

@@ -27,6 +27,7 b' from traitlets import ('
     Float,
 )
 
+from prompt_toolkit.auto_suggest import AutoSuggestFromHistory
 from prompt_toolkit.enums import DEFAULT_BUFFER, EditingMode
 from prompt_toolkit.filters import (HasFocus, Condition, IsDone)
 from prompt_toolkit.formatted_text import PygmentsTokens
@@ -353,18 +354,20 b' class TerminalInteractiveShell(InteractiveShell):'
 
         self.pt_loop = asyncio.new_event_loop()
         self.pt_app = PromptSession(
-                            editing_mode=editing_mode,
-                            key_bindings=key_bindings,
-                            history=history,
-                            completer=IPythonPTCompleter(shell=self),
-                            enable_history_search = self.enable_history_search,
-                            style=self.style,
-                            include_default_pygments_style=False,
-                            mouse_support=self.mouse_support,
-                            enable_open_in_editor=self.extra_open_editor_shortcuts,
-                            color_depth=self.color_depth,
-                            tempfile_suffix=".py",
-                            **self._extra_prompt_options())
+            auto_suggest=AutoSuggestFromHistory(),
+            editing_mode=editing_mode,
+            key_bindings=key_bindings,
+            history=history,
+            completer=IPythonPTCompleter(shell=self),
+            enable_history_search=self.enable_history_search,
+            style=self.style,
+            include_default_pygments_style=False,
+            mouse_support=self.mouse_support,
+            enable_open_in_editor=self.extra_open_editor_shortcuts,
+            color_depth=self.color_depth,
+            tempfile_suffix=".py",
+            **self._extra_prompt_options()
+        )
 
     def _make_style_from_name_or_cls(self, name_or_cls):
         """

docs/source/whatsnew/development.rst

@@ -24,6 +24,75 b' Need to be updated:'
 
 
 
+Autosuggestion is a very useful feature available in `fish <https://fishshell.com/>`__, `zsh <https://en.wikipedia.org/wiki/Z_shell>`__, and `prompt-toolkit <https://python-prompt-toolkit.readthedocs.io/en/master/pages/asking_for_input.html#auto-suggestion>`__.
+
+`Ptpython <https://github.com/prompt-toolkit/ptpython#ptpython>`__ allows users to enable this feature in
+`ptpython/config.py <https://github.com/prompt-toolkit/ptpython/blob/master/examples/ptpython_config/config.py#L90>`__.
+
+This feature allows users to accept autosuggestions with ctrl e, ctrl f,
+or right arrow as described below.
+
+1. Start ipython
+
+.. image:: ../_images/auto_suggest_prompt_no_text.png
+
+2. Run ``print("hello")``
+
+.. image:: ../_images/auto_suggest_print_hello_suggest.png
+
+3. Press p to see the autosuggestion
+
+.. image:: ../_images/auto_suggest_print_hello_suggest.png
+
+4. Press ctrl f, or ctrl e, or right arrow to accept the suggestion
+
+.. image:: ../_images/auto_suggest_print_hello.png
+
+You can also complete word by word:
+
+1. Run ``def say_hello(): print("hello")``
+
+.. image:: ../_images/auto_suggest_second_prompt.png
+
+2. Press d to see the autosuggestion
+
+.. image:: ../_images/audo_suggest_d_phantom.png
+
+3. Press alt f to accept the first word of the suggestion
+
+.. image:: ../_images/auto_suggest_def_phantom.png
+
+Importantly, this feature does not interfere with tab completion:
+
+1. After running ``def say_hello(): print("hello")``, press d
+
+.. image:: ../_images/audo_suggest_d_phantom.png
+
+2. Press Tab to start tab completion
+
+.. image:: ../_images/auto_suggest_d_completions.png
+
+3A. Press Tab again to select the first option
+
+.. image:: ../_images/auto_suggest_def_completions.png
+
+3B. Press alt f to accept to accept the first word of the suggestion
+
+.. image:: ../_images/auto_suggest_def_phantom.png
+
+3C. Press ctrl f or ctrl e to accept the entire suggestion
+
+.. image:: ../_images/auto_suggest_match_parens.png
+
+To install a version of ipython with autosuggestions enabled, run:
+
+``pip install git+https://github.com/mskar/ipython@auto_suggest``
+
+Currently, autosuggestions are only shown in the emacs or vi insert editing modes:
+
+- The ctrl e, ctrl f, and alt f shortcuts work by default in emacs mode.
+- To use these shortcuts in vi insert mode, you will have to create `custom keybindings in your config.py <https://github.com/mskar/setup/commit/2892fcee46f9f80ef7788f0749edc99daccc52f4/>`__.
+
 .. DO NOT EDIT THIS LINE BEFORE RELEASE. FEATURE INSERTION POINT.
 
 As a reminder, IPython master has diverged from the 7.x branch, thus master may