pub fn outcome<'v, T>(
spec: &Spec<'_>,
argv: &[&'v OsStr],
parse_from: impl FnOnce(&[&'v OsStr]) -> Result<T, Error<'static, 'v>>,
) -> Outcome<T>Expand description
What a CLI would do with one command line.
Pass the CLI’s own parse_from — outcome(Ex::spec(), &words.words(), Ex::parse_from) —
which is the function item, not a call. Nothing is printed and nothing exits; the page or
message the process would have produced comes back in the Outcome.
A CLI whose identity is computed at run time (#[usage(version = …)] and its neighbours)
reports its declared spec values here, since the harness has the spec and not the program.
Executable views are the same: this is the plain entry point, and a view is selected by
argv0 in parse_from_argv.
A failure’s text is whatever the build being tested would print: the clap-shaped message
where diagnostics is on, as the facade’s defaults have it, and the compact error where a
parser-only build turned the renderer off.