From 19773a0959364ef7c54f14049c07b030c443cd1a Mon Sep 17 00:00:00 2001
From: Lars Wirzenius <liw@liw.fi>
Date: Thu, 3 Oct 2019 12:38:24 +0300
Subject: Change: Roadmap.step_names to return an iterator

---
 src/lib.rs     |  2 +-
 src/parser.rs  |  2 +-
 src/roadmap.rs | 14 +++++---------
 3 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index c13943d..4eb712a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -19,7 +19,7 @@
 //!   label: The first step
 //! ").unwrap();
 //!
-//! let n = r.step_names();
+//! let n: Vec<&str> = r.step_names().collect();
 //! assert_eq!(n.len(), 2);
 //! assert!(n.contains(&"first"));
 //! assert!(n.contains(&"endgoal"));
diff --git a/src/parser.rs b/src/parser.rs
index f5eaf96..8b0dc05 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -176,7 +176,7 @@ second:
         )
         .unwrap();
 
-        let names = roadmap.step_names();
+        let names: Vec<&str> = roadmap.step_names().collect();
         assert_eq!(names.len(), 2);
         assert!(names.contains(&"first"));
         assert!(names.contains(&"second"));
diff --git a/src/roadmap.rs b/src/roadmap.rs
index 778aa2f..7b78572 100644
--- a/src/roadmap.rs
+++ b/src/roadmap.rs
@@ -25,12 +25,8 @@ impl Roadmap {
     }
 
     /// Return list of step names.
-    pub fn step_names<'a>(&'a self) -> Vec<&'a str> {
-        let mut names = vec![];
-        for step in self.steps.iter() {
-            names.push(step.name());
-        }
-        names
+    pub fn step_names<'a>(&'a self) -> impl Iterator<Item=&str> {
+        self.steps.iter().map(|step| step.name())
     }
 
     /// Get a step, given its name.
@@ -190,7 +186,7 @@ mod tests {
     #[test]
     fn new_roadmap() {
         let roadmap = Roadmap::new();
-        assert_eq!(roadmap.step_names().len(), 0);
+        assert_eq!(roadmap.step_names().count(), 0);
     }
 
     #[test]
@@ -198,8 +194,8 @@ mod tests {
         let mut roadmap = Roadmap::new();
         let first = Step::new("first", "the first step");
         roadmap.add_step(&first).unwrap();
-        assert_eq!(roadmap.step_names().len(), 1);
-        assert_eq!(roadmap.step_names(), vec!["first"]);
+        let names: Vec<&str> = roadmap.step_names().collect();
+        assert_eq!(names, vec!["first"]);
     }
 
     #[test]
-- 
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