Give parser function visibility of choices descriptions

[wsande]

Using an exampple similar to my previous question...

Let's say I have a 'show fruit' command with a completer that produces this when I tab:

ID
=========
1     apple (Fuji)
2     orange (Mandarin)
3     banana (Chiquita)
all   (show all fruit)

When I complete the command and the parser function is called, it gets the ID from the choice provider.
How can I also make the choice descr available to the parser function?

See code below, with my question in the 'show fruit' function.

import cmd2
from typing import  List

def fruit_completer(self) -> List[cmd2.CompletionItem]:
    items = {1:'apple (Fuji)', 2:'orange(Mandarin)', 3:'banana (Chiquita)', 'all':'(show all fruit)' }
    return [cmd2.CompletionItem(item_id, description) for item_id, description in items.items()]

show_parser = cmd2.Cmd2ArgumentParser()
show_subparsers = show_parser.add_subparsers(title='subcommands', help='subcommand help')
parser_show_fruit = show_subparsers.add_parser('fruit', help='show fruit help')
fruit_arg = parser_show_fruit.add_argument('fruit',  choices_provider=fruit_completer, metavar='ID',  descriptive_header='',  help="enter a fruit ID or 'all'")

class SAMPLE_CLI(cmd2.Cmd):
    def __init__(self):
        super().__init__()

    def show_fruit(self, args):
        self.poutput("You chose fruit #{}".format(args.fruit))
        # -----
        # how do I access the arg choice descr string  here?  e.g. 'apple (Fuji)'
        # -----

    parser_show_fruit.set_defaults(func=show_fruit)

    @cmd2.with_argparser(show_parser)
    def do_show(self, args):
        func = getattr(args, 'func', None)
        if func is not None:
            func(self, args)
        else:
            self.do_help('show')

if __name__ == '__main__':
    import sys
    app = SAMPLE_CLI()
    sys.exit(app.cmdloop())

[kmvanbrunt]

CompletionItem data is only used during tab completion to display suggestions and populate the command line. What's passed to your parser is coming from the command line after you press Enter.

Therefore, you'll need to move the items dictionary out of fruit_completer() so it can also be accessed from show_fruit().
Then just use the passed in fruit ID to resolve its description.

[wsande]

Thanks for that! One thing I realized is that if the user just types 'show fruit' instead of using tab completion, the completer never runs (of course) and items never gets populated. So even though I moved it out of fruit_completer(), it was empty.

I fixed this by explicitly calling fruit_completer() at the start of the show_fruit() function, so items is populated whether or not they used tab-completion.

[kmvanbrunt]

Why not just populate the dictionary when you declare it?

fruit_choices = {1:'apple (Fuji)', 2:'orange(Mandarin)', 3:'banana (Chiquita)', 'all':'(show all fruit)'}

def fruit_completer(self) -> List[cmd2.CompletionItem]:
    return [cmd2.CompletionItem(item_id, description) for item_id, description in fruit_choices.items()]

[wsande]

In my real CLI (not this simplified sample), the choices are dynamic, based on context and the current state of the system.