Fix #20

Signed-off-by: Marcello Seri <[email protected]>

bin/doi2bib.ml

@@ -2,9 +2,46 @@ open Doi2bib
 
 let err s = `Error (false, s)
 
+(* Assumes "    url = { THE_URL }," is always well formed *)
+let url_re =
+  Re.compile
+    Re.(
+      seq
+        [
+          bol;
+          group (seq [ rep blank; str "url = {" ]);
+          group (rep (compl [ char '}' ]));
+          str "},";
+        ])
+
+let escape_table =
+  let escapes =
+    List.map
+      (fun s -> Re.compile @@ Re.str s)
+      [ "%2F"; "%28"; "%29"; "%3C"; "%3E"; "%3A"; "%3B" ]
+  in
+  let chars = [ "/"; "("; ")"; "<"; ">"; ":"; ";" ] in
+  List.combine escapes chars
+
+let unescape s =
+  List.fold_left
+    (fun s (re_code, chr) -> Re.replace_string ~all:true re_code ~by:chr s)
+    s escape_table
+
 let process_id outfile id =
   let open Lwt.Syntax in
   let* bibtex = Http.get_bib_entry @@ Parser.parse_id id in
+  let f grp =
+    let prefix = Re.Group.get grp 1 in
+    let url = Re.Group.get grp 2 in
+    String.concat "" [ prefix; unescape url; "}," ]
+  in
+  (* The doi produced by crossref contains %-escaped urls,
+     but %s are comments in bibtex/latex. This is perhaps a
+     brute way of dealing with it but it has been working
+     fine for me on a huge number of examples.
+     See https://github.com/mseri/doi2bib/issues/20 for context*)
+  let bibtex = Re.replace ~all:true url_re ~f bibtex in
   match outfile with
   | "stdout" -> Lwt_io.print bibtex
   | outfile ->

bin/dune

@@ -1,5 +1,5 @@
 (executable
  (name doi2bib)
  (public_name doi2bib)
- (libraries cmdliner doi2bib unix)
+ (libraries cmdliner doi2bib re unix)
  (preprocess future_syntax))