feat: use PyperClipboard if available for ptk

closes #3989

news/feat-clipboard-support.rst

@@ -0,0 +1,27 @@
+**Added:**
+
+* support PTK's clipboard integration if pyperclip is installed.
+So that some common emacs like
+[cut/copy](https://github.com/prompt-toolkit/python-prompt-toolkit/blob/master/examples/prompts/system-clipboard-integration.py)
+will work out of the box.
+
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* <news item>
+
+**Security:**
+
+* <news item>

setup.py

@@ -342,7 +342,7 @@ def main():
     }
     skw["cmdclass"]["develop"] = xdevelop
     skw["extras_require"] = {
-        "ptk": ["prompt-toolkit>=3.0"],
+        "ptk": ["prompt-toolkit>=3.0", "pyperclip"],
         "pygments": ["pygments>=2.2"],
         "mac": ["gnureadline"],
         "linux": ["distro"],

xonsh/ptk_shell/shell.py

@@ -35,6 +35,12 @@ from prompt_toolkit.formatted_text import PygmentsTokens, to_formatted_text
 from prompt_toolkit.styles import merge_styles, Style
 from prompt_toolkit.styles.pygments import pygments_token_to_classname
 
+try:
+    from prompt_toolkit.clipboard.pyperclip import PyperclipClipboard
+
+    SYS_CLIPBOARD = True
+except ImportError:
+    SYS_CLIPBOARD = False
 
 ANSI_OSC_PATTERN = re.compile("\x1b].*?\007")
 CAPITAL_PATTERN = re.compile(r"([a-z])([A-Z])")
@@ -146,7 +152,12 @@ class PromptToolkitShell(BaseShell):
             winutils.enable_virtual_terminal_processing()
         self._first_prompt = True
         self.history = ThreadedHistory(PromptToolkitHistory())
-        self.prompter = PromptSession(history=self.history)
+
+        ptk_args = {"history": self.history}
+        if SYS_CLIPBOARD:
+            ptk_args["clipboard"] = PyperclipClipboard()
+        self.prompter = PromptSession(**ptk_args)
+
         self.prompt_formatter = PTKPromptFormatter(self.prompter)
         self.pt_completer = PromptToolkitCompleter(self.completer, self.ctx, self)
         self.key_bindings = load_xonsh_bindings()