From 618ac89d256adca97518742db2ad2759c4f5fc72 Mon Sep 17 00:00:00 2001
From: Murarth <murarth@gmail.com>
Date: Wed, 26 Jul 2017 15:09:32 -0700
Subject: Add method `String::retain`

Behaves like `Vec::retain`, accepting a predicate `FnMut(char) -> bool`
and reducing the string to only characters for which the predicate
returns `true`.
---
 src/liballoc/tests/lib.rs    |  1 +
 src/liballoc/tests/string.rs | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)

(limited to 'src/liballoc/tests')

diff --git a/src/liballoc/tests/lib.rs b/src/liballoc/tests/lib.rs
index c6d70ee7575..d4f3a89ee99 100644
--- a/src/liballoc/tests/lib.rs
+++ b/src/liballoc/tests/lib.rs
@@ -26,6 +26,7 @@
 #![feature(splice)]
 #![feature(str_checked_slicing)]
 #![feature(str_escape)]
+#![feature(string_retain)]
 #![feature(test)]
 #![feature(unboxed_closures)]
 #![feature(unicode)]
diff --git a/src/liballoc/tests/string.rs b/src/liballoc/tests/string.rs
index b1731b2a5dc..f5c124c6b44 100644
--- a/src/liballoc/tests/string.rs
+++ b/src/liballoc/tests/string.rs
@@ -332,6 +332,26 @@ fn remove_bad() {
     "ศ".to_string().remove(1);
 }
 
+#[test]
+fn test_retain() {
+    let mut s = String::from("α_β_γ");
+
+    s.retain(|_| true);
+    assert_eq!(s, "α_β_γ");
+
+    s.retain(|c| c != '_');
+    assert_eq!(s, "αβγ");
+
+    s.retain(|c| c != 'β');
+    assert_eq!(s, "αγ");
+
+    s.retain(|c| c == 'α');
+    assert_eq!(s, "α");
+
+    s.retain(|_| false);
+    assert_eq!(s, "");
+}
+
 #[test]
 fn insert() {
     let mut s = "foobar".to_string();
-- 
cgit 1.4.1-3-g733a5