Support optional (non-required) positional arguments

[jacobdeichert]

Required arguments use the round brackets like (required_arg) so optional args can probably use square brackets [optional_arg].

## say [phrase]

~~~sh
if [[ $phrase != "" ]]; then
    echo "$phrase"
else
    echo "😶"
fi
~~~

[jacobdeichert]

I'll take this one sometime this week.

[brandonkal]

I would suggest (arg_name?) where the question denotes optional, much like in TypeScript types.

[jacobdeichert]

Hmmm, i like that idea. That would make it very easy to tell what's optional and what's not.

[kivio]

it will be good if we can provide default value

[brendanfalk]

I would suggest following traditional shell syntax for brackets: [optional]

[jacobdeichert]

I would suggest following traditional shell syntax for brackets: [optional]

Yeah, agree that sticking with traditional shell syntax is better – going to go with [optional] instead of (optional?) 👍

[jacobdeichert]

it will be good if we can provide default value

Maybe like this: [optional=default_value] ?

Still thinking about this... named flags don't have support for a default value yet either. If we add it here, we should add to named flags as well.

[brendanfalk]

Could also do traditional shell syntax for mandatory args: <required> as opposed to current (required)

[jacobdeichert]

Could also do traditional shell syntax for mandatory args: <required> as opposed to current (required)

Yeah, I originally had that but then changed it in #16 because a few markdown renderers I noticed were interpreting <required> args as html :/

I might have to take another look at that and see which renderers (like GitHub, or VS Code markdown preview) break... can't remember off the top of my head.

[brendanfalk]

Maybe like this: [optional=default_value]?

If we add it here, we should add to named flags as well.

These both make sense. Just make sure to only set default values for optional args not required ones!