src/token.rs

use crate::algorithm::Printer;
use proc_macro2::{Delimiter, Ident, Literal, Spacing, TokenStream, TokenTree};

impl Printer {
    pub fn single_token(&mut self, token: Token, group_contents: fn(&mut Self, TokenStream)) {
        match token {
            Token::Group(delimiter, stream) => self.token_group(delimiter, stream, group_contents),
            Token::Ident(ident) => self.ident(&ident),
            Token::Punct(ch, _spacing) => self.token_punct(ch),
            Token::Literal(literal) => self.token_literal(&literal),
        }
    }

    fn token_group(
        &mut self,
        delimiter: Delimiter,
        stream: TokenStream,
        group_contents: fn(&mut Self, TokenStream),
    ) {
        self.delimiter_open(delimiter);
        if !stream.is_empty() {
            if delimiter == Delimiter::Brace {
                self.space();
            }
            group_contents(self, stream);
            if delimiter == Delimiter::Brace {
                self.space();
            }
        }
        self.delimiter_close(delimiter);
    }

    pub fn ident(&mut self, ident: &Ident) {
        self.word(ident.to_string());
    }

    pub fn token_punct(&mut self, ch: char) {
        self.word(ch.to_string());
    }

    pub fn token_literal(&mut self, literal: &Literal) {
        self.word(literal.to_string());
    }

    pub fn delimiter_open(&mut self, delimiter: Delimiter) {
        self.word(match delimiter {
            Delimiter::Parenthesis => "(",
            Delimiter::Brace => "{",
            Delimiter::Bracket => "[",
            Delimiter::None => return,
        });
    }

    pub fn delimiter_close(&mut self, delimiter: Delimiter) {
        self.word(match delimiter {
            Delimiter::Parenthesis => ")",
            Delimiter::Brace => "}",
            Delimiter::Bracket => "]",
            Delimiter::None => return,
        });
    }
}

pub enum Token {
    Group(Delimiter, TokenStream),
    Ident(Ident),
    Punct(char, Spacing),
    Literal(Literal),
}

impl From<TokenTree> for Token {
    fn from(tt: TokenTree) -> Self {
        match tt {
            TokenTree::Group(group) => Token::Group(group.delimiter(), group.stream()),
            TokenTree::Ident(ident) => Token::Ident(ident),
            TokenTree::Punct(punct) => Token::Punct(punct.as_char(), punct.spacing()),
            TokenTree::Literal(literal) => Token::Literal(literal),
        }
    }
}