Trait manyhow::FunctionMacroHandler

pub trait FunctionMacroHandler<Function> {
    type Input;
    type Dummy;
    type Output;

    // Required method
    fn call(
        self,
        item: Self::Input,
        dummy: &mut Self::Dummy,
        emitter: &mut Emitter
    ) -> Self::Output;
}

Input of a function proc-macro

Note: for TokenStream either proc_macro::TokenStream or proc_macro2::TokenStream can be used.

Trait is implemented for any function, taking in one TokenStream. Additionally, they can take optionally in any order a &mut Emitter which allows emitting errors without returning early. And a &mut TokenStream to return a dummy TokenStream on failure.

When used with function() it must return a type implementing MacroOutput, with function! it can accept types implementing Parse and return types implementing ToTokens.

Required Associated Types

type Input

type Dummy

type Output

Required Methods

fn call( self, item: Self::Input, dummy: &mut Self::Dummy, emitter: &mut Emitter ) -> Self::Output

Implementors

impl<Input, Dummy: Clone, Output, Function> FunctionMacroHandler<(Input, &mut Dummy, &mut Emitter, Output)> for Function

where Function: Fn(Input, &mut Dummy, &mut Emitter) -> Output,

type Dummy = Dummy

type Input = Input

type Output = Output

impl<Input, Dummy: Clone, Output, Function> FunctionMacroHandler<(Input, &mut Dummy, Output)> for Function

where Function: Fn(Input, &mut Dummy) -> Output,

type Dummy = Dummy

type Input = Input

type Output = Output

impl<Input, Output, Function> FunctionMacroHandler<(Input, &mut Emitter, Output)> for Function

where Function: Fn(Input, &mut Emitter) -> Output,

type Dummy = TokenStream

type Input = Input

type Output = Output

impl<Input, Output, Function> FunctionMacroHandler<(Input, Output)> for Function

where Function: Fn(Input) -> Output,

type Dummy = TokenStream

type Input = Input

type Output = Output