Comma separated value support for settings arrays / enumerables

[sandreas]

Is your feature request related to a problem? Please describe.
Let's say you can define multiple colors for an enum array:

myapp --color="red" --color="green" --color="blue" --color="yellow"

I'm a bit frustrated, that I have to provide the option parameter 4 times, because it could be much shorter just providing the options with a separator.

Describe the solution you'd like

[CommandOption("--color", Separator = ",")]
public MyColor[] RemoveAdditionalFields { get; init; } = Array.Empty<MyColor>();

myapp --color="red,green,blue,yellow"

Describe alternatives you've considered

myapp --color "red" "green" "blue" "yellow"

What do you think?

[phil-scott-78]

Made this a discussion. You should be able to accomplish this with a TypeConverter though.

[sandreas]

Made this a discussion. You should be able to accomplish this with a TypeConverter though.

Could you give a spectre.console specific example? That would be really helpful.

[phil-scott-78]

You bet. I'm using a TypeConverter here that that could be repurposed hopefully pretty easy.

https://github.com/phil-scott-78/dotnet-soddi/blob/main/src/Soddi/LogCommandOptions.cs#L15

[sandreas]

Thank you very much.

[sandreas]

Mmh, today I found the time to check this out, but unfortunately, there is a problem:

public class CommaSeparatedStringConverter : TypeConverter
{
    public override object ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value)
    {
        if (value is not string stringValue)
        {
            throw new NotSupportedException("Can't convert value to verbosity.");
        }
        
        return stringValue.Split(",");
    }
}

Just splitting the string would not work - and since there is a type change (from string to array), is this really possible with a TypeConverter?

Here is another approach - result is:

Error: Object cannot be stored in an array of this type.

Details

System.InvalidCastException: Object cannot be stored in an array of this type. at System.Array.InternalSetValue(Object value, IntPtr flattenedIndex) at System.Array.SetValue(Object value, Int32 index) at Spectre.Console.Cli.CommandValueBinder.GetArray(CommandParameter parameter, Object value) in /_/src/Spectre.Console/Cli/Internal/Binding/CommandValueBinder.cs:line 88 at Spectre.Console.Cli.CommandValueBinder.Bind(CommandParameter parameter, ITypeResolver resolver, Object value) in /_/src/Spectre.Console/Cli/Internal/Binding/CommandValueBinder.cs:line 20 at Spectre.Console.Cli.CommandValueResolver.GetParameterValues(CommandTree tree, ITypeResolver resolver) in /_/src/Spectre.Console/Cli/Internal/Binding/CommandValueResolver.cs:line 88 at Spectre.Console.Cli.CommandBinder.Bind(CommandTree tree, Type settingsType, ITypeResolver resolver) in /_/src/Spectre.Console/Cli/Internal/CommandBinder.cs:line 7 at Spectre.Console.Cli.CommandExecutor.Execute(CommandTree leaf, CommandTree tree, CommandContext context, ITypeResolver resolver, IConfiguration configuration) in /_/src/Spectre.Console/Cli/Internal/CommandExecutor.cs:line 97 at Spectre.Console.Cli.CommandExecutor.Execute(IConfiguration configuration, IEnumerable`1 args) in /_/src/Spectre.Console/Cli/Internal/CommandExecutor.cs:line 78 at Spectre.Console.Cli.CommandApp.RunAsync(IEnumerable`1 args) in /_/src/Spectre.Console/Cli/CommandApp.cs:line 81

public class DumpCommandSettings : CommandSettingsBase
{
    
    [CommandOption("--include-property")]
    [TypeConverter(typeof(CommaSeparatedStringConverter<MetadataProperty>))]
    public MetadataProperty[] IncludeProperties { get; set; } = Array.Empty<MetadataProperty>();
}

public class CommaSeparatedStringConverter<T> : ArrayConverter where T : struct, IConvertible
{
    public override bool CanConvertFrom(ITypeDescriptorContext? context, Type sourceType)
    {
        if (sourceType == typeof(string))
        {
            return true;
        }

        return base.CanConvertFrom(context, sourceType);
    }

    public override object? ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value)
    {
        if (value is not string s || string.IsNullOrEmpty(s))
        {
            return base.ConvertFrom(context, culture, value);
        }

        var results = s.Split(",");
        var parsedResults = new List<T>();
        foreach (var result in results)
        {
            if (!Enum.TryParse<T>(result, true, out var parsedResult))
            {
                continue;
            }

            parsedResults.Add(parsedResult);
        }

        return parsedResults.ToArray();
    }
}

[rcdailey]

This really needs some proper attention. I'm trying to migrate away from CliFx to Spectre.Console, but I cannot do this:

mycommand.exe --configs file1 file2 file3

To me this seems like a basic requirement. Many POSIX CLI applications on linux support this. Just require positional arguments before any options, and this is easy to parse AFAICS.