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use erl_tokenize::LexicalToken; use std; use std::marker::PhantomData; use crate::traits::{Preprocessor, TokenRead}; use crate::{Error, Result}; #[derive(Debug)] pub struct TokenReader<T, E> { inner: T, unread: Vec<LexicalToken>, _phantom: PhantomData<E>, } impl<T, E> TokenReader<T, E> where T: Iterator<Item = std::result::Result<LexicalToken, E>> + Preprocessor, Error: From<E>, { pub fn new(inner: T) -> Self { TokenReader { inner, unread: Vec::new(), _phantom: PhantomData, } } pub fn inner(&self) -> &T { &self.inner } pub fn inner_mut(&mut self) -> &mut T { &mut self.inner } pub fn into_inner(self) -> T { self.inner } } impl<T, E> Preprocessor for TokenReader<T, E> where T: Preprocessor, { fn define_macro(&mut self, name: &str, replacement: Vec<LexicalToken>) { self.inner.define_macro(name, replacement); } fn undef_macro(&mut self, name: &str) { self.inner.undef_macro(name); } } impl<T, E> TokenRead for TokenReader<T, E> where T: Iterator<Item = std::result::Result<LexicalToken, E>> + Preprocessor, Error: From<E>, { fn try_read_token(&mut self) -> Result<Option<LexicalToken>> { match self.unread.pop().map(Ok).or_else(|| self.inner.next()) { None => Ok(None), Some(Err(e)) => Err(e.into()), Some(Ok(t)) => Ok(Some(t)), } } fn unread_token(&mut self, token: LexicalToken) { self.unread.push(token); } }