Trait enumscribe::TryScribeCowStr

pub trait TryScribeCowStr {
    fn try_scribe(&self) -> Option<Cow<'static, str>>;
}

Trait for converting an enum to a clone-on-write string, or None if the conversion fails.

Like all of the traits provided by enumscribe, this should not be implemented manually; use #[derive(TryScribeCowStr)] provided by the enumscribe_derive crate instead.

When deriving this trait, you may specify the string that a particular variant should be converted to by annotating it with #[enumscribe(str = "foo")]. If this is omitted, the name of the variant will be used instead.

A maximum of one variant can be annotated with #[enumscribe(other)]. This variant must have exactly one field, which must implement Into<String>. Converting this variant to a string will result in whatever the value of its field is.

You may also annotate a variant with #[enumscribe(ignore)], in which case attempting to convert the variant to a string will always result in None.

use std::borrow::Cow;

use enumscribe::TryScribeCowStr;

#[derive(TryScribeCowStr, PartialEq, Eq, Debug)]
enum Airport {
    #[enumscribe(ignore)]
    Heathrow,
    #[enumscribe(str = "LGW")]
    Gatwick,
    #[enumscribe(other)]
    Other(String),
}

assert_eq!(Airport::Heathrow.try_scribe(),
           None);
assert_eq!(Airport::Gatwick.try_scribe(),
           Some(Cow::Borrowed("LGW")));
assert_eq!(Airport::Other("STN".to_owned()).try_scribe(),
           Some(Cow::Owned::<'static, str>("STN".to_owned())));

Required methods

fn try_scribe(&self) -> Option<Cow<'static, str>>

Converts this enum to a Option<Cow<'static, str>>.

Calling this method on a variant marked with #[enumscribe(ignore)] will return None.

When called on a variant marked with #[enumscribe(other)], the variant’s field will be returned as a Cow::Owned. For other variants, a Cow::Borrowed is returned, containing a static string slice determined by the #[enumscribe(str = "...")] attribute, or the name of the variant if the attribute is omitted.

Implementors