fn main() {
let features = [
"span-value-usize",
"span-value-u128",
"span-value-u64",
"span-value-u32",
"span-value-u16",
"span-value-u8",
];
let mut selected_features = 0;
for feature in features {
println!("{:?}", std::env::vars().collect::<Vec<_>>());
if std::env::var(format!(
"CARGO_FEATURE_{}",
feature.to_uppercase().replace("-", "_")
))
.is_ok()
{
selected_features += 1;
}
}
if selected_features == 0 {
panic!("Error: You must choose a span value type; enable a feature.");
}
if selected_features > 1 {
panic!(
"Error: You can only pick one span value type; please disable {} of your {selected_features} features.",
selected_features - 1
);
}
}