From b469f8b1e360f1169e9a2d4e6de382c63502c72b Mon Sep 17 00:00:00 2001
From: stuebinm
Date: Fri, 3 Sep 2021 00:02:33 +0200
Subject: somewhat pointless generalisation of a type signature

There's no real reason for this other than that I wanted to know if
abstracting over &[T] -> T and &str -> String etc. was possible.
---
 isabelle-unicode/src/lib.rs | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/isabelle-unicode/src/lib.rs b/isabelle-unicode/src/lib.rs
index 8394e57..30a7cec 100644
--- a/isabelle-unicode/src/lib.rs
+++ b/isabelle-unicode/src/lib.rs
@@ -1,13 +1,15 @@
 
 symbolmacro::make_symbols!();
 
-// TODO: is it possible to be polymorphic over slice types here?
 pub trait PrettyUnicode {
-    fn to_pretty_unicode(self) -> Option<String>;
+    type Owned: core::borrow::Borrow<Self>;
+    fn to_pretty_unicode(&self) -> Option<Self::Owned>;
 }
 
-impl PrettyUnicode for &str {
-    fn to_pretty_unicode(self) -> Option<String> {
+impl PrettyUnicode for str {
+    type Owned = String;
+
+    fn to_pretty_unicode(&self) -> Option<Self::Owned> {
         // split at escape sequences
         let mut chunks = self.split("\\<");
 
@@ -30,7 +32,7 @@ impl PrettyUnicode for &str {
 
                 // how much of the rest do we need?
                 let offset = ident?
-                .len()
+                    .len()
                     + 1;
                 Some((symbol, &chunk[offset..]))
             })
-- 
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