Add App::name set function to use crate_name!() macro

[SuperFluffy]

Currently, you can further specify the about, authors, and version field of an App through setter methods of the same, and pull in the appropriate value through crate_about!() and similar macros. Only crate_name!() is special, in that we can only use it when constructing a new App through App::new.

If we construct an app through App::from_yaml, we have no way of setting the name to the one in Cargo.toml through the macro. It would be great to be able to set the name after App was constructed.

Is it possible to add this or is there a reason why this was omitted?

[kbknapp]

It's not omiited on purpose,probably just overlooked. Until I get a chance to add this (I recently broke my finger so am typing with one hand and it's not feasible to get real work done 😞) there is a workaround (that is technically public, but its not meant to be public and is undocumented. As such it may change in the future without warning):

let mut app = // load YAML like normal
app.p.meta.name = "Some Name".into();
let m = app.get_matches();

If someone would like to submit a PR with this, it'd be an easy one just adding the fn to src/app/mod.rs!

[SuperFluffy]

Sorry about your hand. :( To make it heal faster I submitted #910.

[larsrh]

What I find a bit strange here is that I need to use a dummy name in the YAML file, because otherwise clap does some strange stuff:

        let mut a = if let Some(name) = yaml["name"].as_str() {
            App::new(name)
        } else {
            let yaml_hash = yaml.as_hash().unwrap();
            let sc_key = yaml_hash.keys().nth(0).unwrap();
            is_sc = Some(yaml_hash.get(sc_key).unwrap());
            App::new(sc_key.as_str().unwrap())
        };