Function offer_install 

pub fn offer_install(
    reader: &mut impl BufRead,
    out: &Output,
    installer: &Installer<'_>,
) -> Result<Option<PathBuf>>

Asks whether to install Ghola and installs it on a yes. Returns the installed binary.

An install that fails is reported with the manual steps, and the run goes on without Ghola.

Errors

Returns the prompt’s read or write error.