Simplify, update Changes

Author: nojb

Changes

@@ -47,6 +47,12 @@ Working version
   (Sébastien Briais, review by Daniel Buenzli, Alain Frisch and
   Gabriel Scherer)
 
+- PR#7515, GPR#1147: Arg.align now optionally uses the tab character '\t' to
+  separate the "unaligned" and "aligned" parts of the documentation string. If
+  tab is not present, then space is used as a fallback. Allows to have spaces in
+  the unaligned part, which is useful for Tuple options.
+  (Nicolas Ojeda Bar, review by Alain Frisch and Gabriel Scherer)
+
 - GPR#1034: Add List.init
   (Richard Degenne, review by David Allsopp, Thomas Braibant, Florian
   Angeletti, Gabriel Scherer, Nathan Moreau, Alain Frisch)
@@ -61,11 +67,6 @@ Working version
 
 - Resurrect tabulation boxes in module Format. Rewrite/extend documentation
   of tabulation boxes.
-- PR#7515, GPR#1147: Arg.align now optionally uses the tab character '\t' to
-  separate the "unaligned" and "aligned" parts of the documentation string. If
-  tab is not present, then space is used as a fallback. Allows to have spaces in the
-  unaligned part, which is useful for Tuple options.
-  (Nicolas Ojeda Bar, review by ...)
 
 ### Compiler user-interface and warnings:
 

stdlib/arg.ml

@@ -313,7 +313,7 @@ let second_word s =
   | n -> loop (n+1)
   | exception Not_found ->
       begin match String.index s ' ' with
-      | n -> loop n
+      | n -> loop (n+1)
       | exception Not_found -> len
       end
 
@@ -324,9 +324,9 @@ let max_arg_len cur (kwd, spec, doc) =
   | _ -> max cur (String.length kwd + second_word doc)
 
 
-let replace_leading_tab s n =
+let replace_leading_tab s =
   let seen = ref false in
-  String.init n (fun i -> match s.[i] with '\t' when not !seen -> seen := true; ' ' | c -> c)
+  String.map (function '\t' when not !seen -> seen := true; ' ' | c -> c) s
 
 let add_padding len ksd =
   match ksd with
@@ -337,16 +337,16 @@ let add_padding len ksd =
   | (kwd, (Symbol _ as spec), msg) ->
       let cutcol = second_word msg in
       let spaces = String.make ((max 0 (len - cutcol)) + 3) ' ' in
-      (kwd, spec, "\n" ^ spaces ^ replace_leading_tab msg (String.length msg))
+      (kwd, spec, "\n" ^ spaces ^ replace_leading_tab msg)
   | (kwd, spec, msg) ->
       let cutcol = second_word msg in
       let kwd_len = String.length kwd in
       let diff = len - kwd_len - cutcol in
       if diff <= 0 then
-        (kwd, spec, replace_leading_tab msg (String.length msg))
+        (kwd, spec, replace_leading_tab msg)
       else
         let spaces = String.make diff ' ' in
-        let prefix = replace_leading_tab msg cutcol in
+        let prefix = String.sub (replace_leading_tab msg) 0 cutcol in
         let suffix = String.sub msg cutcol (String.length msg - cutcol) in
         (kwd, spec, prefix ^ spaces ^ suffix)