From b5720e2b3fd2daa367264ca6412db397e18257ae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gutyina=20Gerg=C5=91?= <gutyina.gergo.2@gmail.com>
Date: Tue, 27 May 2025 22:21:08 +0200
Subject: [PATCH] lib/strings: init replaceString

---
 lib/default.nix    |  1 +
 lib/strings.nix    | 35 +++++++++++++++++++++++++++++++++++
 lib/tests/misc.nix | 11 +++++++++++
 3 files changed, 47 insertions(+)

diff --git a/lib/default.nix b/lib/default.nix
index 63e02882e2c3..6f8530296044 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -309,6 +309,7 @@ let
         stringLength
         substring
         isString
+        replaceString
         replaceStrings
         intersperse
         concatStringsSep
diff --git a/lib/strings.nix b/lib/strings.nix
index ba8c47b69037..ca97e5b4658b 100644
--- a/lib/strings.nix
+++ b/lib/strings.nix
@@ -332,6 +332,41 @@ rec {
   */
   concatLines = concatMapStrings (s: s + "\n");
 
+  /**
+    Given string `s`, replace every occurrence of the string `from` with the string `to`.
+
+    # Inputs
+
+    `from`
+    : The string to be replaced
+
+    `to`
+    : The string to replace with
+
+    `s`
+    : The original string where replacements will be made
+
+    # Type
+
+    ```
+    replaceString :: string -> string -> string -> string
+    ```
+
+    # Examples
+    :::{.example}
+    ## `lib.strings.replaceString` usage example
+
+    ```nix
+    replaceString "world" "Nix" "Hello, world!"
+    => "Hello, Nix!"
+    replaceString "." "_" "v1.2.3"
+    => "v1_2_3"
+    ```
+
+    :::
+  */
+  replaceString = from: to: replaceStrings [ from ] [ to ];
+
   /**
     Repeat a string `n` times,
     and concatenate the parts into a new string.
diff --git a/lib/tests/misc.nix b/lib/tests/misc.nix
index 0d8377ec6006..437714a2822e 100644
--- a/lib/tests/misc.nix
+++ b/lib/tests/misc.nix
@@ -91,6 +91,7 @@ let
     range
     recursiveUpdateUntil
     removePrefix
+    replaceString
     replicate
     runTests
     setFunctionArgs
@@ -497,6 +498,11 @@ runTests {
     expected = "/usr/include:/usr/local/include";
   };
 
+  testReplaceStringString = {
+    expr = strings.replaceString "." "_" "v1.2.3";
+    expected = "v1_2_3";
+  };
+
   testReplicateString = {
     expr = strings.replicate 5 "hello";
     expected = "hellohellohellohellohello";
@@ -1728,6 +1734,11 @@ runTests {
     ];
   };
 
+  testReplaceString = {
+    expr = replaceString "world" "Nix" "Hello, world!";
+    expected = "Hello, Nix!";
+  };
+
   testReplicate = {
     expr = replicate 3 "a";
     expected = [