Skip to main content

ToKeyString

Trait ToKeyString

pub trait ToKeyString: Sized {
    // Required method
    fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result;

    // Provided method
    fn with_key_string<R>(&self, f: impl FnOnce(&str) -> R) -> R { ... }
}

Expand description

A trait for converting an attribute key to a string.

Used for performing path comparisons and for constructing error messages when using arbitrary types as attribute keys. Currently only used by the ParseMetaItem implementations for BTreeMap and HashMap.

Required Methods§

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

Formats the given value as a key string.

Provided Methods§

fn with_key_string<R>(&self, f: impl FnOnce(&str) -> R) -> R

Runs function f with the key converted to a &str.

Can be specialized by values that can pass a cheaply borrowed &str. The default implementation calls f with the result from key_to_string.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types§

impl ToKeyString for ()

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

fn with_key_string<R>(&self, f: impl FnOnce(&str) -> R) -> R

impl ToKeyString for AngleBracketedGenericArguments

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for BareFnArg

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for BinOp

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for BoundLifetimes

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Expr

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for ExprArray

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for ExprAssign

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for ExprCall

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for ExprCast

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for ExprField

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for ExprIndex

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for ExprLit

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for ExprMethodCall

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for ExprParen

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for ExprPath

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for ExprRange

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for ExprRepeat

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for ExprTuple

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for FnArg

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for GenericParam

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Group

Available on crate feature proc-macro only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Ident

Available on crate feature proc-macro only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Ident

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for IpAddr

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Ipv4Addr

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Ipv6Addr

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Lifetime

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for LifetimeParam

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Lit

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for LitBool

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for LitByte

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for LitByteStr

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for LitChar

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for LitFloat

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for LitInt

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for LitStr

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Literal

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Literal

Available on crate feature proc-macro only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Meta

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for MetaList

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for MetaNameValue

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for NonZeroI8

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for NonZeroI16

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for NonZeroI32

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for NonZeroI64

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for NonZeroI128

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for NonZeroIsize

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for NonZeroU8

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for NonZeroU16

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for NonZeroU32

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for NonZeroU64

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for NonZeroU128

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for NonZeroUsize

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for OsString

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

fn with_key_string<R>(&self, f: impl FnOnce(&str) -> R) -> R

impl ToKeyString for ParenthesizedGenericArguments

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Pat

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Path

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for PathBuf

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

fn with_key_string<R>(&self, f: impl FnOnce(&str) -> R) -> R

impl ToKeyString for PathSegment

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Punct

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Punct

Available on crate feature proc-macro only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Receiver

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Signature

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for SocketAddr

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for SocketAddrV4

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for SocketAddrV6

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for String

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

fn with_key_string<R>(&self, f: impl FnOnce(&str) -> R) -> R

impl ToKeyString for TokenStream

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TokenStream

Available on crate feature proc-macro only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TokenTree

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TokenTree

Available on crate feature proc-macro only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TraitBound

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Type

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TypeArray

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TypeBareFn

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TypeImplTrait

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TypeParamBound

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TypePath

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TypePtr

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TypeReference

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TypeSlice

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TypeTraitObject

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for TypeTuple

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for UnOp

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for UseTree

Available on crate feature full only.

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for Visibility

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for WherePredicate

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for char

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for f32

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for f64

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for i8

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for i16

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for i32

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for i64

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for i128

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for isize

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for u16

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for u32

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for u64

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for u128

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl ToKeyString for usize

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<'t, T: ToKeyString + Clone> ToKeyString for Cow<'t, T>

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

fn with_key_string<R>(&self, f: impl FnOnce(&str) -> R) -> R

impl<K, V> ToKeyString for BTreeMap<K, V>
where K: ToKeyString + Ord, V: ToKeyString,

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<K, V> ToKeyString for HashMap<K, V>
where K: ToKeyString + Hash + Eq, V: ToKeyString,

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString, T3: ToKeyString, T4: ToKeyString, T5: ToKeyString, T6: ToKeyString, T7: ToKeyString, T8: ToKeyString, T9: ToKeyString, T10: ToKeyString, T11: ToKeyString, T12: ToKeyString, T13: ToKeyString, T14: ToKeyString, T15: ToKeyString> ToKeyString for (T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString, T3: ToKeyString, T4: ToKeyString, T5: ToKeyString, T6: ToKeyString, T7: ToKeyString, T8: ToKeyString, T9: ToKeyString, T10: ToKeyString, T11: ToKeyString, T12: ToKeyString, T13: ToKeyString, T14: ToKeyString> ToKeyString for (T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString, T3: ToKeyString, T4: ToKeyString, T5: ToKeyString, T6: ToKeyString, T7: ToKeyString, T8: ToKeyString, T9: ToKeyString, T10: ToKeyString, T11: ToKeyString, T12: ToKeyString, T13: ToKeyString> ToKeyString for (T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString, T3: ToKeyString, T4: ToKeyString, T5: ToKeyString, T6: ToKeyString, T7: ToKeyString, T8: ToKeyString, T9: ToKeyString, T10: ToKeyString, T11: ToKeyString, T12: ToKeyString> ToKeyString for (T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString, T3: ToKeyString, T4: ToKeyString, T5: ToKeyString, T6: ToKeyString, T7: ToKeyString, T8: ToKeyString, T9: ToKeyString, T10: ToKeyString, T11: ToKeyString> ToKeyString for (T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString, T3: ToKeyString, T4: ToKeyString, T5: ToKeyString, T6: ToKeyString, T7: ToKeyString, T8: ToKeyString, T9: ToKeyString, T10: ToKeyString> ToKeyString for (T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString, T3: ToKeyString, T4: ToKeyString, T5: ToKeyString, T6: ToKeyString, T7: ToKeyString, T8: ToKeyString, T9: ToKeyString> ToKeyString for (T0, T1, T2, T3, T4, T5, T6, T7, T8, T9)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString, T3: ToKeyString, T4: ToKeyString, T5: ToKeyString, T6: ToKeyString, T7: ToKeyString, T8: ToKeyString> ToKeyString for (T0, T1, T2, T3, T4, T5, T6, T7, T8)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString, T3: ToKeyString, T4: ToKeyString, T5: ToKeyString, T6: ToKeyString, T7: ToKeyString> ToKeyString for (T0, T1, T2, T3, T4, T5, T6, T7)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString, T3: ToKeyString, T4: ToKeyString, T5: ToKeyString, T6: ToKeyString> ToKeyString for (T0, T1, T2, T3, T4, T5, T6)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString, T3: ToKeyString, T4: ToKeyString, T5: ToKeyString> ToKeyString for (T0, T1, T2, T3, T4, T5)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString, T3: ToKeyString, T4: ToKeyString> ToKeyString for (T0, T1, T2, T3, T4)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString, T3: ToKeyString> ToKeyString for (T0, T1, T2, T3)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString, T2: ToKeyString> ToKeyString for (T0, T1, T2)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString, T1: ToKeyString> ToKeyString for (T0, T1)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T0: ToKeyString> ToKeyString for (T0,)

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T: ToKeyString + Copy> ToKeyString for Cell<T>

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

fn with_key_string<R>(&self, f: impl FnOnce(&str) -> R) -> R

impl<T: ToKeyString + Hash + Eq> ToKeyString for HashSet<T>

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T: ToKeyString + Ord> ToKeyString for BTreeSet<T>

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T: ToKeyString + Ord> ToKeyString for BinaryHeap<T>

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T: ToKeyString, P: ToTokens> ToKeyString for Punctuated<T, P>

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T: ToKeyString, const N: usize> ToKeyString for [T; N]

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T: ToKeyString> ToKeyString for Box<T>

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

fn with_key_string<R>(&self, f: impl FnOnce(&str) -> R) -> R

impl<T: ToKeyString> ToKeyString for LinkedList<T>

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T: ToKeyString> ToKeyString for Option<T>

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T: ToKeyString> ToKeyString for Rc<T>

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

fn with_key_string<R>(&self, f: impl FnOnce(&str) -> R) -> R

impl<T: ToKeyString> ToKeyString for RefCell<T>

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

fn with_key_string<R>(&self, f: impl FnOnce(&str) -> R) -> R

impl<T: ToKeyString> ToKeyString for Vec<T>

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

impl<T: ToKeyString> ToKeyString for VecDeque<T>

fn fmt_key_string(&self, f: &mut Formatter<'_>) -> Result

Implementors§

impl<'a> ToKeyString for SmallString<'a>