Start of new argparse completion example

Author: kmvanbrunt

examples/argparse_completion.py

@@ -0,0 +1,73 @@
+#!/usr/bin/env python
+# coding=utf-8
+"""
+A simple example demonstrating how to integrate tab completion with argparse-based commands.
+"""
+import argparse
+from typing import List
+
+from cmd2 import Cmd, Cmd2ArgumentParser, with_argparser
+from cmd2.utils import basic_complete
+
+food_item_strs = ['Pizza', 'Ham', 'Ham Sandwich', 'Potato']
+
+# This data is used to demonstrate delimiter_complete
+file_strs = \
+    [
+        '/home/user/file.db',
+        '/home/user/file space.db',
+        '/home/user/another.db',
+        '/home/other user/maps.db',
+        '/home/other user/tests.db'
+    ]
+
+
+def choices_function() -> List[str]:
+    """Choices functions are useful when the choice list is dynamically generated (e.g. from data in a database)"""
+    return ['a', 'dynamic', 'list']
+
+
+def completer_function(text: str, line: str, begidx: int, endidx: int) -> List[str]:
+    """
+    A tab completion function not dependent on instance data. Since custom tab completion operations commonly
+    need to modify cmd2's instance variables related to tab completion, it will be rare to need a completer
+    function. completer_method should be used in those cases.
+    """
+    return basic_complete(text, line, begidx, endidx, food_item_strs)
+
+
+class ArgparseCompletion(Cmd):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.sport_item_strs = ['Bat', 'Basket', 'Basketball', 'Football', 'Space Ball']
+
+    def choices_method(self) -> List[str]:
+        """Choices methods are useful when the choice list is based on instance data of your application"""
+        return self.sport_item_strs
+
+    # Parser for complete command
+    complete_parser = Cmd2ArgumentParser(description="Command demonstrating tab completion with argparse\n"
+                                                     "Notice even the flags of this command tab complete")
+
+    # Tab complete from a list using argparse choices. Set metavar if you don't
+    # want the entire choices list showing in the usage text for this command.
+    complete_parser.add_argument('--choices', choices=food_item_strs, metavar="CHOICE")
+
+    # Tab complete from choices provided by a choices function and choices method
+    complete_parser.add_argument('--choices_function', choices_function=choices_function)
+    complete_parser.add_argument('--choices_method', choices_method=choices_method)
+
+    # Tab complete using a completer function and completer method
+    complete_parser.add_argument('--completer_function', completer_function=completer_function)
+    complete_parser.add_argument('--completer_method', completer_method=Cmd.path_complete)
+
+    @with_argparser(complete_parser)
+    def do_complete(self, _: argparse.Namespace) -> None:
+        """The complete command"""
+        self.poutput("I do nothing")
+
+
+if __name__ == '__main__':
+    import sys
+    app = ArgparseCompletion()
+    sys.exit(app.cmdloop())