optimise drop_start

1 files changed, 7 insertions, 3 deletions

diff --git a/src/gleam/string.gleam b/src/gleam/string.gleam
index 8f6b5cb..00d58ad 100644
--- a/src/gleam/string.gleam
+++ b/src/gleam/string.gleam
@@ -246,9 +246,13 @@ pub fn drop_left(from string: String, up_to num_graphemes: Int) -> String {
 /// ```
 ///
 pub fn drop_start(from string: String, up_to num_graphemes: Int) -> String {
-  case num_graphemes < 0 {
-    True -> string
-    False -> slice(string, num_graphemes, length(string) - num_graphemes)
+  case num_graphemes > 0 {
+    False -> string
+    True ->
+      case pop_grapheme(string) {
+        Ok(#(_, string)) -> drop_start(string, num_graphemes - 1)
+        Error(Nil) -> string
+      }
   }
 }