1 files changed, 21 insertions, 0 deletions
diff --git a/stdlib/string.ml b/stdlib/string.ml
index 7eafec02f..f3906f353 100644
--- a/stdlib/string.ml
+++ b/stdlib/string.ml
@@ -85,6 +85,27 @@ external is_printable: char -> bool = "caml_is_printable"
 external char_code: char -> int = "%identity"
 external char_chr: int -> char = "%identity"
 
+let is_space = function
+  | ' ' | '\012' | '\n' | '\r' | '\t' -> true
+  | _ -> false
+
+let trim s =
+  let len = length s in
+  let i = ref 0 in
+  while !i < len && is_space (unsafe_get s !i) do
+    incr i
+  done;
+  let j = ref (len - 1) in
+  while !j >= !i && is_space (unsafe_get s !j) do
+    decr j
+  done;
+  if !i = 0 && !j = len - 1 then
+    s
+  else if !j >= !i then
+    sub s !i (!j - !i + 1)
+  else
+    ""
+
 let escaped s =
   let n = ref 0 in
     for i = 0 to length s - 1 do