diff --git a/src/replacer/line_replacer.rs b/src/replacer/line_replacer.rs
new file mode 100644
index 0000000..3ebd879
--- /dev/null
+++ b/src/replacer/line_replacer.rs
@@ -0,0 +1,44 @@
+#[derive(Debug)]
+pub struct Pair {
+    regex: regex::Regex,
+    rep: String,
+}
+
+#[derive(Debug)]
+pub enum Opt {
+    ReplaceLineIfMatch,
+    AnotherOption,
+}
+
+pub fn replace_line<P: AsRef<[Pair]>, S: AsRef<str>>(
+    pairs: P,
+    opts: Vec<Opt>,
+    content: S,
+) -> Vec<String> {
+    let pairs = pairs.as_ref();
+    let content = content.as_ref();
+
+    let mut lines = content.lines().map(|x| x.to_owned()).collect::<Vec<_>>();
+
+    for opt in opts {
+        match opt {
+            Opt::ReplaceLineIfMatch => replace_line_if_match(pairs, &mut lines),
+            Opt::AnotherOption => other(pairs, &mut lines),
+        }
+    }
+    lines
+}
+
+fn replace_line_if_match(pairs: &[Pair], lines: &mut Vec<String>) {
+    for line in lines.iter_mut() {
+        for Pair { regex, rep } in pairs {
+            if regex.is_match(&line) {
+                *line = rep.clone();
+            }
+        }
+    }
+}
+
+fn other(pairs: &[Pair], lines: &mut Vec<String>) {
+    unimplemented!()
+}
diff --git a/src/replacer.rs b/src/replacer/mod.rs
similarity index 100%
rename from src/replacer.rs
rename to src/replacer/mod.rs