Use boxed iterators instead of Vecs. This should also reduce a few
memory allocations.
---
Reworded the commit message.

Sorry for sending this multiple times, still learning the email
workflow.

 src/sed/edit.rs | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/src/sed/edit.rs b/src/sed/edit.rs
index 695778a..c80cde1 100644
--- a/src/sed/edit.rs
+++ b/src/sed/edit.rs
@@ -20,7 +20,7 @@ use super::parser::parse_substitute;
 use super::types::{Address, Command, Substitute};
 
 use itertools::Itertools;
-use std::iter::repeat;
+use std::iter::{empty, once, repeat};
 
 fn regex_replace<'a, I>(lines: I, arg: &str) -> Result<String, String>
 where
@@ -59,14 +59,14 @@ pub fn edit(text: &str, cmd: Command) -> Result<String, String> {
     let repeating_arg = repeat(arg.as_ref()).take(count);
 
     let tmp;
-    let edited = match command {
-        'a' => editing_range.interleave_shortest(repeating_arg).collect(),
-        'c' => vec![arg.as_ref()],
-        'd' => vec![],
-        'i' => repeating_arg.interleave_shortest(editing_range).collect(),
+    let edited: Box<dyn Iterator<Item = &str>> = match command {
+        'a' => Box::new(editing_range.interleave_shortest(repeating_arg)),
+        'c' => Box::new(once(arg.as_ref())),
+        'd' => Box::new(empty()),
+        'i' => Box::new(repeating_arg.interleave_shortest(editing_range)),
         's' => {
             tmp = regex_replace(editing_range, &arg)?;
-            vec![tmp.as_ref()]
+            Box::new(once(tmp.as_ref()))
         }
         _ => return Err(format!("Sed command `{}` not implemented!", command)),
     };
@@ -76,5 +76,6 @@ pub fn edit(text: &str, cmd: Command) -> Result<String, String> {
         .take(start)
         .chain(edited)
         .chain(text.split('\n').skip(start + count))
-        .join("\n"))
+        .intersperse("\n")
+        .collect())
 }
-- 
2.27.0

Thanks for the patch! I'll push this later.

-- 
Hannu Hartikainen