1 unstable release
0.1.0 | Jul 8, 2024 |
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#20 in #validate
6KB
valistr
Creating immutable string wrapper types with values validated with regexes.
TL;DR
use valistr::valistr;
/// A valid identifier in PascalCase. The regex used here is not perfect, but it's good enough for demonstration.
#[valistr(r"([A-Z][a-z0-9]*)+")]
struct PascalCaseId;
#[valistr(r"(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})")]
struct Date;
fn main() {
// Create it with `new` method.
let id = PascalCaseId::new("HelloWorld").unwrap();
// `Debug` and `Display` are implemented.
assert_eq!(format!("{}", id), "HelloWorld");
assert_eq!(format!("{:?}", id), "\"HelloWorld\"");
// `Deref<Target = String>` is implemented, so methods of `String` can be called directly.
assert_eq!(id.as_str(), "HelloWorld");
// `new` returns `None` if the input is not valid.
assert!(PascalCaseId::new("helloWorld").is_none());
// `TryFrom<&str>` and `TryFrom<String>` is also implemented.
assert!(PascalCaseId::try_from("HelloWorld").is_ok());
assert!(PascalCaseId::try_from("hello_world".to_string()).is_err());
// For each named capture group `x`, a method `fn get_x(&self) -> Option<&str>` is provided.
//
// Note that the method will be generated only if the name matches `[a-z][a-z0-9_]*`. This
// constraint guarantees the generated method name is a valid and clean Rust identifier.
let date = Date::new("2023-08-18").unwrap();
assert_eq!(date.get_year().unwrap(), "2023");
assert_eq!(date.get_month().unwrap(), "08");
assert_eq!(date.get_day().unwrap(), "18");
}
Dependencies
~2.3–4MB
~69K SLoC