{ lib, buildOcaml, ocaml, fetchurl }: if lib.versionAtLeast ocaml.version "4.06" then throw "estring is not available for OCaml ${ocaml.version}" else buildOcaml rec { pname = "estring"; version = "1.3"; src = fetchurl { url = "https://forge.ocamlcore.org/frs/download.php/1012/estring-${version}.tar.gz"; sha256 = "0b6znz5igm8pp28w4b7sgy82rpd9m5aw6ss933rfbw1mrh05gvcg"; }; meta = with lib; { homepage = "http://estring.forge.ocamlcore.org/"; description = "Extension for string literals"; license = licenses.bsd3; }; }