From 105690e5e7789bb3721390d1ae9600b5bb280b7b Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Wed, 30 Mar 2022 23:54:36 +0100
Subject: [PATCH] Drop IteratorExt extension trait

We used this once.  Not a successful experiment I think.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 apitest/atmain.rs | 21 +++++++++++---------
 src/utils.rs      | 50 -----------------------------------------------
 2 files changed, 12 insertions(+), 59 deletions(-)

diff --git a/apitest/atmain.rs b/apitest/atmain.rs
index 647499c6..7b73a08b 100644
--- a/apitest/atmain.rs
+++ b/apitest/atmain.rs
@@ -235,13 +235,15 @@ pub struct PieceInfo<I> {
 impl Session {
   #[throws(Explode)]
   fn pieces<PI:Idx>(&self) -> Pieces<PI> {
-    let pieces = self.dom
-      .element("#pieces_marker")
-      .unwrap().next_siblings()
-      .map_loop(|puse: ego_tree::NodeRef<scraper::Node>| {
+    let pieces = {
+      let mut pieces: Pieces<PI> = default();
+      for puse in self.dom
+        .element("#pieces_marker")
+        .unwrap().next_siblings()
+      {
         let puse = puse.value();
-        let puse = puse.as_element().ok_or(Loop::Continue)?;
-        let attr = puse.attr("data-info").ok_or(Loop::Break)?;
+        if_let!{ Some(puse) = puse.as_element(); else continue; };
+        if_let!{ Some(attr) = puse.attr("data-info"); else break; };
         let pos = Pos::from_iter(["x","y"].iter().map(|attr|{
           puse
             .attr(attr).unwrap()
@@ -250,9 +252,10 @@ impl Session {
         let id = puse.id.as_ref().unwrap();
         let id = id.strip_prefix("use").unwrap().to_string();
         let info = serde_json::from_str(attr).unwrap();
-        Loop::ok(PieceInfo { id, pos, info })
-      })
-      .collect();
+        pieces.push(PieceInfo { id, pos, info });
+      }
+      pieces
+    };
     let nick = self.nick;
     dbgc!(nick, &pieces);
     pieces
diff --git a/src/utils.rs b/src/utils.rs
index 3dbfae0c..d6030d0f 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -266,62 +266,12 @@ macro_rules! deref_to_field_mut {
   }
 }
 
-#[derive(Debug)]
-pub enum Loop<E> {
-  Continue,
-  Break,
-  Error(E),
-}
-impl<E> From<E> for Loop<E> {
-  fn from(e: E) -> Loop<E> { Loop::Error(e) }
-}
-impl Loop<Infallible> {
-  pub fn ok<T>(t: T) -> Result<T,Loop<Infallible>> { Ok(t) }
-}
-
-pub trait IteratorExt<U,E,F>: Iterator
-  where F: FnMut(Self::Item) -> Result<U,Loop<E>>,
-{
-  type Return: Iterator<Item=U>;
-  fn map_loop(self, f: F) -> Self::Return where E: EmptyType;
-
-  type TryReturn: Iterator<Item=Result<U,E>>;
-  fn try_map_loop(self, f: F) -> Self::TryReturn;
-}
-
 pub trait EmptyType { fn diverge<T>(self) -> T; }
 
 impl EmptyType for Infallible {
   fn diverge<T>(self) -> T { match self { } }
 }
 
-impl<T,U,E,F> IteratorExt<U,E,F> for T where
-  T: Iterator,
-  F: FnMut(Self::Item) -> Result<U,Loop<E>>,
-{
-  type Return = impl Iterator<Item=U>;
-  fn map_loop(self, f: F) -> Self::Return where E: EmptyType {
-    self
-      .map(f)
-      .filter(|i| !matches!(i, Err(Loop::Continue)))
-      .take_while(|i| !matches!(i, Err(Loop::Break)))
-      .map(|i| i.ok().unwrap())
-  }
-
-  type TryReturn = impl Iterator<Item=Result<U,E>>;
-  fn try_map_loop(self, f: F) -> Self::TryReturn {
-    self
-      .map(f)
-      .filter(|i| matches!(i, Err(Loop::Continue)))
-      .take_while(|i| matches!(i, Err(Loop::Break)))
-      .map(|i| match i {
-        Ok(y) => Ok(y),
-        Err(Loop::Error(e)) => Err(e),
-        _ => panic!(),
-      })
-  }
-}
-
 #[macro_export] // <- otherwise bogus warning `unused_macros`
 macro_rules! matches_doesnot_yn2bool {
   (=) => (true);
-- 
2.30.2