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#!/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, CompletionError, CompletionItem
from cmd2.utils import basic_complete
# Data source for argparse.choices
food_item_strs = ['Pizza', 'Ham', 'Ham Sandwich', 'Potato']
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', 'goes', 'here']
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.
"""
match_against = ['a', 'dynamic', 'list', 'goes', 'here']
return basic_complete(text, line, begidx, endidx, match_against)
def choices_completion_item() -> List[CompletionItem]:
"""Return CompletionItem instead of strings. These give more context to what's being tab completed."""
items = {
1: "My item",
2: "Another item",
3: "Yet another item"
}
return [CompletionItem(item_id, description) for item_id, description in items.items()]
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
def choices_completion_error(self) -> List[str]:
"""
CompletionErrors can be raised if an error occurs while tab completing.
Example use cases
- Reading a database to retrieve a tab completion data set failed
- A previous command line argument that determines the data set being completed is invalid
"""
if self.debug:
return self.sport_item_strs
raise CompletionError("Debug must be true")
# 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)
# Demonstrate raising a CompletionError while tab completing
complete_parser.add_argument('--completion_error', choices_method=choices_completion_error)
# Demonstrate returning CompletionItems instead of strings
complete_parser.add_argument('--completion_item', choices_function=choices_completion_item, metavar="ITEM_ID",
descriptive_header="Description")
@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())
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