Trait MacroArg

pub trait MacroArg: Sized {
    // Required method
    fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>;
}

A type that can be parsed as an argument to a macro.

This is often implemented by delegating to syn’s Parse.

However, sometimes it can behave differently. For example, nested MacroKeywordArgs require surrounding braces {} when parsed as a MacroArg, but not when parsed via syn’s Parse.

This gives the effect of requiring braces when nested (as a MacroArg), but not at the top level (via syn’s Parse).

Required Methods

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

Parse the argument to the macro

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl MacroArg for Meta

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for Expr

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for GenericParam

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for Lit

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for Visibility

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for Type

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for bool

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for char

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for f32

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for f64

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for i8

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for i16

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for i32

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for i64

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for isize

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for u8

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for u16

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for u32

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for u64

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for usize

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for String

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for Ident

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for Lifetime

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for LitBool

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for LitFloat

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for LitInt

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for LitStr

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl MacroArg for Path

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

impl<T: MacroArg> MacroArg for Option<T>

Parses an optional MacroArg, always returning the Some variant

The None variant will only be generated if the argument is missing

fn parse_macro_arg(stream: ParseStream<'_>) -> Result<Self>

Implementors

impl<K, V> MacroArg for KeyValuePair<K, V>

where K: MacroDictKey, V: MacroArg,

impl<K: MacroKeywordArgs> MacroArg for ParsedKeywordArguments<K>

impl<K: MacroDictKey, V: MacroArg> MacroArg for NestedDict<K, V>

impl<T> MacroArg for Syn<T>

where T: Parse,

impl<T, P> MacroArg for NestedList<T, P>

where T: MacroArg, P: Parse,

impl<T: MacroArg> MacroArg for ExplicitOption<T>