From 5ef85352ed0c533570b1e3d9022732f7cb6474ce Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 12 Jul 2020 16:10:49 +0100
Subject: [PATCH] change api of svg_x_defs

---
 src/gamestate.rs | 9 +++++++--
 src/pieces.rs    | 4 ++--
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/gamestate.rs b/src/gamestate.rs
index 40294eb9..8aed7d08 100644
--- a/src/gamestate.rs
+++ b/src/gamestate.rs
@@ -68,12 +68,17 @@ type SE = SVGProcessingError;
 type SR = Result<(),SE>;
 
 pub trait Piece : Send + Debug {
+  // #[throws] doesn't work here for some reason
   fn svg_piece(&self, f: &mut String, pri: &PieceRenderInstructions) -> SR;
+
   #[throws(SE)]
   fn outline_path(&self, pri : &PieceRenderInstructions) -> String;
+
   #[throws(SE)]
   fn surround_path(&self, pri : &PieceRenderInstructions) -> String;
-  fn svg_x_defs(&self, pri : &PieceRenderInstructions) -> String;
+
+  fn svg_x_defs(&self, f: &mut String, pri : &PieceRenderInstructions) -> SR;
+
   #[throws(SE)]
   fn thresh_dragraise(&self, pri : &PieceRenderInstructions)
                       -> Option<Coord>;
@@ -143,7 +148,7 @@ impl PieceState {
     write!(defs,
            r##"<path id="select{}" stroke="black" fill="none" d="{}"/>"##,
            pri.id, pr.p.surround_path(&pri)?)?;
-    write!(defs, "{}", pr.p.svg_x_defs(&pri))?;
+    pr.p.svg_x_defs(&mut defs, &pri)?;
     defs
   }
 
diff --git a/src/pieces.rs b/src/pieces.rs
index a595b567..c679e8a6 100644
--- a/src/pieces.rs
+++ b/src/pieces.rs
@@ -101,8 +101,8 @@ impl Piece for SimpleShape {
                       -> Option<Coord> {
     Some(self.approx_dia / 2)
   }
-  fn svg_x_defs(&self, _pri : &PieceRenderInstructions) -> String {
-    "".to_owned()
+  #[throws(SE)]
+  fn svg_x_defs(&self, _f: &mut String, _pri : &PieceRenderInstructions) {
   }
   #[throws(SE)]
   fn describe_html(&self, face : Option<FaceId>) -> String {
-- 
2.30.2