From 518edf281f93cceb9793224f700a8f3d63d78ea2 Mon Sep 17 00:00:00 2001
From: Martin Fischer <martin@push-f.com>
Date: Wed, 27 Sep 2023 17:19:27 +0200
Subject: break!: remove Emitter::pop_token, use Iterator instead

---
 src/default_emitter.rs | 14 ++++++++------
 src/emitter.rs         | 11 +----------
 src/naive_parser.rs    |  4 ++--
 src/tokenizer.rs       |  6 +++---
 4 files changed, 14 insertions(+), 21 deletions(-)

(limited to 'src')

diff --git a/src/default_emitter.rs b/src/default_emitter.rs
index 9d5ab52..7ef96ec 100644
--- a/src/default_emitter.rs
+++ b/src/default_emitter.rs
@@ -33,9 +33,15 @@ impl<O> Default for DefaultEmitter<O> {
     }
 }
 
-impl<O: Offset> Emitter<O> for DefaultEmitter<O> {
-    type Token = Token<O>;
+impl<O> Iterator for DefaultEmitter<O> {
+    type Item = Token<O>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.emitted_tokens.pop_back()
+    }
+}
 
+impl<O: Offset> Emitter<O> for DefaultEmitter<O> {
     fn emit_eof(&mut self) {
         self.flush_current_characters();
     }
@@ -44,10 +50,6 @@ impl<O: Offset> Emitter<O> for DefaultEmitter<O> {
         self.push_error(error, span);
     }
 
-    fn pop_token(&mut self) -> Option<Self::Token> {
-        self.emitted_tokens.pop_back()
-    }
-
     fn emit_string(&mut self, s: &str) {
         self.current_characters.push_str(s);
     }
diff --git a/src/emitter.rs b/src/emitter.rs
index 311c73c..923da1c 100644
--- a/src/emitter.rs
+++ b/src/emitter.rs
@@ -24,21 +24,12 @@ use crate::Error;
 
 #[allow(unused_variables)] // workaround for https://github.com/rust-lang/rust/issues/91074
 pub trait Emitter<O> {
-    /// The token type emitted by this emitter. This controls what type of values the [`Tokenizer`](crate::Tokenizer)
-    /// yields when used as an iterator.
-    type Token;
-
-    /// The state machine has reached the end of the file. It will soon call `pop_token` for the
-    /// last time.
+    /// The state machine has reached the end of the file.
     fn emit_eof(&mut self);
 
     /// A (probably recoverable) parsing error has occurred.
     fn emit_error(&mut self, error: Error, span: Range<O>);
 
-    /// After every state change, the tokenizer calls this method to retrieve a new token that can
-    /// be returned via the tokenizer's iterator interface.
-    fn pop_token(&mut self) -> Option<Self::Token>;
-
     /// Emit a bunch of plain characters as character tokens.
     fn emit_string(&mut self, c: &str);
 
diff --git a/src/naive_parser.rs b/src/naive_parser.rs
index 93c37d7..10eb98d 100644
--- a/src/naive_parser.rs
+++ b/src/naive_parser.rs
@@ -65,9 +65,9 @@ impl<R, O, E> Iterator for NaiveParser<R, O, E>
 where
     R: Reader + Position<O>,
     O: Offset,
-    E: Emitter<O>,
+    E: Emitter<O> + Iterator,
 {
-    type Item = Result<E::Token, R::Error>;
+    type Item = Result<E::Item, R::Error>;
 
     fn next(&mut self) -> Option<Self::Item> {
         loop {
diff --git a/src/tokenizer.rs b/src/tokenizer.rs
index a37a832..f4c0c48 100644
--- a/src/tokenizer.rs
+++ b/src/tokenizer.rs
@@ -373,13 +373,13 @@ impl<O, R, E> Iterator for Tokenizer<R, O, E>
 where
     O: Offset,
     R: Reader + Position<O>,
-    E: Emitter<O>,
+    E: Emitter<O> + Iterator,
 {
-    type Item = Result<Event<E::Token>, R::Error>;
+    type Item = Result<Event<E::Item>, R::Error>;
 
     fn next(&mut self) -> Option<Self::Item> {
         loop {
-            if let Some(token) = self.emitter.pop_token() {
+            if let Some(token) = self.emitter.next() {
                 return Some(Ok(Event::Token(token)));
             }
 
-- 
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