stdcompat dependency

[hannesm]

Dear Madam or Sir,

first of all thanks for maintaining this package. I've some trouble with the stdcompat dependency (which fails to install for me, reported ocamllibs/stdcompat#28).

So, I looked into OCaml 4.08 and omd without stdcompat, and the only two functions used from Stdcompat are List.find_map and String.for_all. Would you accept a patch (see below) that removes the stdcompat dependency (since omd requires OCaml 4.08).

WDYT?

diff --git a/dune-project b/dune-project
index e4dec6f..5270431 100644
--- a/dune-project
+++ b/dune-project
@@ -26,7 +26,6 @@ package installs both the OMD library and the command line tool `omd`.")
  (tags (org:ocamllabs org:mirage))
  (depends
   (ocaml (>= 4.08))
-   stdcompat
    uutf
    uucp
    uunf
diff --git a/omd.opam b/omd.opam
index b6dd14a..6011e09 100644
--- a/omd.opam
+++ b/omd.opam
@@ -23,7 +23,6 @@ bug-reports: "https://github.com/ocaml/omd/issues"
 depends: [
   "dune" {>= "2.7"}
   "ocaml" {>= "4.08"}
-  "stdcompat"
   "uutf"
   "uucp"
   "uunf"
diff --git a/src/dune b/src/dune
index 47c7825..45ccf64 100644
--- a/src/dune
+++ b/src/dune
@@ -1,7 +1,7 @@
 (library
  (name omd)
  (public_name omd)
- (libraries uutf uucp uunf stdcompat))
+ (libraries uutf uucp uunf))
 
 (rule
  (with-stdout-to
diff --git a/src/parser.ml b/src/parser.ml
index 5fbf669..d6ae4f9 100644
--- a/src/parser.ml
+++ b/src/parser.ml
@@ -1,5 +1,4 @@
 open Ast.Impl
-open Stdcompat
 
 type 'attr link_def =
   { label : string
@@ -1618,6 +1617,14 @@ let get_buf buf =
 let text buf acc =
   if Buffer.length buf = 0 then acc else Pre.R (Text ([], get_buf buf)) :: acc
 
+let for_all p s =
+  let n = String.length s in
+  let rec loop i =
+    if i = n then true
+    else if p (String.unsafe_get s i) then loop (succ i)
+    else false in
+  loop 0
+
 let inline_pre buf acc st =
   let pos = pos st in
   let rec gobble_open_backtick n =
@@ -1631,7 +1638,7 @@ let inline_pre buf acc st =
         let finish () =
           let content = Buffer.contents bufcode in
           let content =
-            if String.for_all (fun c -> c = ' ') content then content
+            if for_all (fun c -> c = ' ') content then content
             else if
               String.length content >= 2
               && content.[0] = ' '
diff --git a/src/strSlice.ml b/src/strSlice.ml
index 01a9e79..2a21682 100644
--- a/src/strSlice.ml
+++ b/src/strSlice.ml
@@ -1,5 +1,3 @@
-open Stdcompat
-
 type t =
   { base : string
   ; off : int
diff --git a/src/toc.ml b/src/toc.ml
index f962762..d2b5003 100644
--- a/src/toc.ml
+++ b/src/toc.ml
@@ -1,5 +1,4 @@
 open Ast.Util
-open Stdcompat
 
 let rec remove_links inline =
   match inline with
@@ -59,8 +58,16 @@ let rec find_start headers level number subsections =
 
 let unordered_list items = List ([], Bullet '*', Tight, items)
 
+let rec find_map f = function
+  | [] -> None
+  | x :: l ->
+     begin match f x with
+       | Some _ as result -> result
+       | None -> find_map f l
+     end
+
 let find_id attributes =
-  List.find_map
+  find_map
     (function k, v when String.equal "id" k -> Some v | _ -> None)
     attributes
 

[hannesm]

(alternatively, the lower bound for OCaml could be increased to 4.13 -- I think this is as well fine, since most users of omd won't use old OCaml compilers)

[shonfeder]

Hi! Sounds like your patch is a good idea: I didn't realise stdcompat was so brittle (tho I see I also filed an issue there awhile back.)

Thanks for the patch!

[hannesm]

Thanks for your reply, @shonfeder. What is the plan forward in terms of OCaml version lower bound? Is just putting it on 4.13 fine with you? I opened #305 that requires OCaml 4.13 (with 5.0 out, I don't think maintaining old 4.x Stdlibs is worth it).