From e984e025295f8175808dd0319a5679a4e7f938c3 Mon Sep 17 00:00:00 2001
From: Richard Newman <rnewman@twinql.com>
Date: Wed, 12 Apr 2017 10:56:59 -0700
Subject: [PATCH] Pre: comment RcCounter.

---
 core/src/counter.rs | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/core/src/counter.rs b/core/src/counter.rs
index d51faa5f..f32c0027 100644
--- a/core/src/counter.rs
+++ b/core/src/counter.rs
@@ -20,11 +20,24 @@ pub struct RcCounter {
     c: Rc<AtomicUsize>,
 }
 
+/// A simple shared counter.
 impl RcCounter {
     pub fn new() -> Self {
         RcCounter { c: Rc::new(AtomicUsize::new(0)) }
     }
 
+    /// Return the next value in the sequence.
+    ///
+    /// ```
+    /// use mentat_core::counter::RcCounter;
+    ///
+    /// let c = RcCounter::with_initial(3);
+    /// assert_eq!(c.next(), 3);
+    /// assert_eq!(c.next(), 4);
+    /// let d = c.clone();
+    /// assert_eq!(d.next(), 5);
+    /// assert_eq!(c.next(), 6);
+    /// ```
     pub fn next(&self) -> usize {
         self.c.fetch_add(1, Ordering::SeqCst)
     }