1 files changed, 26 insertions, 0 deletions
diff --git a/stdlib/char.ml b/stdlib/char.ml
new file mode 100644
index 000000000..348c5683c
--- /dev/null
+++ b/stdlib/char.ml
@@ -0,0 +1,26 @@
+(* Character operations *)
+
+external code: char -> int = "%identity"
+external unsafe_chr: int -> char = "%identity"
+
+let chr n =
+  if n < 0 or n > 255 then invalid_arg "Char.chr" else unsafe_chr n
+
+external is_printable: char -> bool = "is_printable"
+
+let escaped = function
+    '\'' -> "\\'"
+  | '\\' -> "\\\\"
+  | '\n' -> "\\n"
+  | '\t' -> "\\t"
+  | c ->  if is_printable c then
+            String.make 1 c
+          else begin
+            let n = code c in
+            let s = String.create 4 in
+            String.unsafe_set s 0 '\\';
+            String.unsafe_set s 1 (unsafe_chr (48 + n / 100));
+            String.unsafe_set s 2 (unsafe_chr (48 + (n / 10) mod 10));
+            String.unsafe_set s 3 (unsafe_chr (48 + n mod 10));
+            s
+          end