Give more information to suggestion function

[svick]

As far as I can tell, when specifying ArgumentsRule for an argument, the options for specifying suggestions are:

• static list: public static ArgumentsRule WithSuggestionsFrom(this ArgumentsRule rule, params string[] values)
• dynamic list based on the current value of the argument: public static ArgumentsRule WithSuggestionsFrom(this ArgumentsRule rule, Func<string, IEnumerable<string>> suggest)

But for https://github.com/dotnet/cli/issues/9172, I would like for the suggestion function to know not just the value of the argument being suggested, but also values of other arguments. That way, e.g. dotnet add package Microsoft.CodeAnalysis -v <Tab> could get the name of the package (Microsoft.CodeAnalysis) to query an API for a list of its versions.

The necessary information seems to be already contained in the ParseResult that's passed to ArgumentsRule.Suggest(), but there doesn't seem to be a way to access that from the suggestion function.

Or am I missing something and there is already a way to do this?

[KathleenDollard]

We're exploring options for improving the command parsing within .NET.

Are you looking at this just in the context of #9172, or are you also using the parser for other purposes (via fork, copy, etc.)?

[svick]

@KathleenDollard

Are you looking at this just in the context of #9172, or are you also using the parser for other purposes (via fork, copy, etc.)?

I'm not using the parser myself, I'm asking just for https://github.com/dotnet/cli/issues/9172. This was the most reasonable way I could think of of implementing that.