From e4016739aec4f6487edec2f1e8aeed48159f1ff1 Mon Sep 17 00:00:00 2001
From: Noah Pendleton <2538614+noahp@users.noreply.github.com>
Date: Fri, 18 Oct 2024 12:10:26 -0400
Subject: [PATCH] Add a test case and doc for `${1}` group reference

---
 README.md       | 4 ++++
 src/replacer.rs | 5 +++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 2e04543..d19069b 100644
--- a/README.md
+++ b/README.md
@@ -80,6 +80,10 @@ ruplacer '(\w+), (\w+)' '$2 $1'
 
 (note the use of single quotes to avoid any processing by the shell)
 
+`${1}` and `${2}` are also supported as an alternative to `$1` and `$2`, see
+[reference
+here](https://docs.rs/regex/1.5.5/regex/struct.Regex.html#replacement-string-syntax).
+Useful if the replacement string is immediately adjacent to literal text.
 
 If you don't want the pattern to be used as a regex, use the `--no-regex` command line flag.
 
diff --git a/src/replacer.rs b/src/replacer.rs
index b26b54c..b7fa110 100644
--- a/src/replacer.rs
+++ b/src/replacer.rs
@@ -362,9 +362,10 @@ mod tests {
     fn test_regex_with_substitutions() {
         let input = "first, second";
         let regex = Regex::new(r"(\w+), (\w+)").unwrap();
-        let query = Query::regex(regex, r"$2 $1");
+        // ensure ${1}text syntax works as expected
+        let query = Query::regex(regex, r"$2 ${1}third");
         let replacement = replace(input, &query).unwrap();
-        assert_eq!(replacement.output(), "second first");
+        assert_eq!(replacement.output(), "second firstthird");
     }
 
     #[test]