From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 30 Apr 2022 15:43:44 +0000 (+0100)
Subject: Introduce and use PiceTrait downcaste_piece extension methoc
X-Git-Tag: otter-1.1.0~391
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=193d99e3ac678932be576c40e836d248cd57a206;p=otter.git

Introduce and use PiceTrait downcaste_piece extension methoc

This is more convenient.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/src/currency.rs b/src/currency.rs
index 8d6784a9..1dad79f6 100644
--- a/src/currency.rs
+++ b/src/currency.rs
@@ -131,11 +131,10 @@ impl PieceTrait for Banknote {
   {
     ig.fastsplit_split(player, tpiece, show, new_z,
       move |_: &IOccults, _: &GameOccults, gpl: &GPlayer,
-            tgpc: &mut GPiece, tipc: &IPiece, tipc_p: &dyn PieceTrait,
+            tgpc: &mut GPiece, _tipc: &IPiece, tipc_p: &dyn PieceTrait,
             ngpc: &mut GPiece|
   {
-    let self_: &Banknote = tipc_p.downcast_ref::<Banknote>()
-      .ok_or_else(|| internal_error_bydebug(tipc))?;
+    let self_: &Banknote = tipc_p.downcast_piece()?;
 
     let tgpc_value: &mut Value = tgpc.xdata.get_mut_exp()?;
     let remaining = tgpc_value.qty.checked_sub(take)
diff --git a/src/fastsplit.rs b/src/fastsplit.rs
index 4a80c5ff..847d6a16 100644
--- a/src/fastsplit.rs
+++ b/src/fastsplit.rs
@@ -136,12 +136,10 @@ impl InstanceGuard<'_> {
       fastsplit:     tgpc.fastsplit,
     };
 
-    let tipc_p = (||{
-      let p = tipc.p.show(show);
-      let p: &Piece = p.downcast_ref::<Piece>()?;
-      let p = p.ipc.as_ref()?.p.show(show);
-      Some(p)
-    })().ok_or_else(|| internal_error_bydebug(tipc))?;
+    let tipc_p = tipc.p
+      .show(show).downcast_piece::<Piece>()?
+      .ipc.as_ref().ok_or_else(|| internal_error_bydebug(tipc))?
+      .p.show(show);
 
     let (t_pu, t_unprepared) = implementation(
       &ig.ioccults, &ig.gs.occults, gpl,
diff --git a/src/gamestate.rs b/src/gamestate.rs
index ff2f0806..57af8d30 100644
--- a/src/gamestate.rs
+++ b/src/gamestate.rs
@@ -421,6 +421,15 @@ impl Timestamp {
   }
 }
 
+#[ext(pub)]
+impl<'r> &'r dyn PieceTrait {
+  #[throws(IE)]
+  fn downcast_piece<P: PieceTrait>(self) -> &'r P {
+    self.downcast_ref::<P>().ok_or_else(|| internal_logic_error(format!(
+      "downcaste_piece failure! got: {:?}", &self)))?
+  }
+}
+
 // ---------- positions and ClampTable ----------
 
 #[derive(Error,Debug,Copy,Clone)]