ToTokens in proc_macro - Rust (original) (raw)

pub trait ToTokens {
    // Required method
    fn to_tokens(&self, tokens: &mut TokenStream);

    // Provided methods
    fn to_token_stream(&self) -> TokenStream { ... }
    fn into_token_stream(self) -> TokenStream
       where Self: Sized { ... }
}

🔬This is a nightly-only experimental API. (proc_macro_totokens #130977)

Expand description

Types that can be interpolated inside a quote! invocation.

Source

🔬This is a nightly-only experimental API. (proc_macro_totokens #130977)

Write self to the given TokenStream.

§Example

Example implementation for a struct representing Rust paths likestd::cmp::PartialEq:

#![feature(proc_macro_totokens)]

use std::iter;
use proc_macro::{Spacing, Punct, TokenStream, TokenTree, ToTokens};

pub struct Path {
    pub global: bool,
    pub segments: Vec<PathSegment>,
}

impl ToTokens for Path {
    fn to_tokens(&self, tokens: &mut TokenStream) {
        for (i, segment) in self.segments.iter().enumerate() {
            if i > 0 || self.global {
                // Double colon `::`
                tokens.extend(iter::once(TokenTree::from(Punct::new(':', Spacing::Joint))));
                tokens.extend(iter::once(TokenTree::from(Punct::new(':', Spacing::Alone))));
            }
            segment.to_tokens(tokens);
        }
    }
}

Source

🔬This is a nightly-only experimental API. (proc_macro_totokens #130977)

Convert self directly into a TokenStream object.

This method is implicitly implemented using to_tokens, and acts as a convenience method for consumers of the ToTokens trait.

Source

🔬This is a nightly-only experimental API. (proc_macro_totokens #130977)

Convert self directly into a TokenStream object.

This method is implicitly implemented using to_tokens, and acts as a convenience method for consumers of the ToTokens trait.

Source §

🔬This is a nightly-only experimental API. (proc_macro_totokens #130977)

Source §

🔬This is a nightly-only experimental API. (proc_macro_totokens #130977)