diff --git a/lib/mem/copy.q b/lib/mem/copy.q
new file mode 100644
index 0000000..c85aa43
--- /dev/null
+++ b/lib/mem/copy.q
@@ -0,0 +1,11 @@
+copy(to string, from string) {
+	len := from.len
+
+	if to.len < len {
+		len = to.len
+	}
+
+	loop i := 0..len {
+		to[i] = from[i]
+	}
+}
\ No newline at end of file
diff --git a/lib/strings/concat.q b/lib/strings/concat.q
index 3f7c537..cba4eb1 100644
--- a/lib/strings/concat.q
+++ b/lib/strings/concat.q
@@ -2,14 +2,7 @@ import mem
 
 concat(a string, b string) -> !string {
 	combined := mem.alloc(a.len + b.len)
-
-	loop i := 0..a.len {
-		combined[i] = a[i]
-	}
-
-	loop i := 0..b.len {
-		combined[a.len+i] = b[i]
-	}
-
+	mem.copy(combined, a)
+	mem.copy(combined[a.len..], b)
 	return combined
 }
\ No newline at end of file