Option<Vec<T> as argument

[aurabindo]

Hi,

An argument with Option<Vec> does not seem to work. Are there any workarounds ?

#[derive(StructOpt, Debug)]
pub enum DevCmds {
    #[structopt(name = "list", alias = "show")]
    Cmd1 {
        optional_args: Option<Vec<String>>,
    },

This produces errors like:

error[E0277]: the trait bound `std::vec::Vec<T>: std::str::FromStr` is not satisfied

[TeXitoi]

Why not just Vec?

[jdm204]

Hi, I can't speak for @aurabindo, but for my use case I'd like to differentiate between

./my-app                                                     // None
./my-app --optional-multiple                       // Some(vec![])
./my-app --optional-multiple ARG1 ARG2  // Some(vec![ARG1, ARG2])

is this currently possible without Option<Vec<T>>? Thanks for your work on structopt!

[TeXitoi]

That's not possible with structopt today. That's a structopt limitation, clap allows to do that.