dnl Copyright (c) 2015-present, Facebook, Inc.
dnl
dnl This source code is licensed under the MIT license found in the
dnl LICENSE file in the root directory of this source tree.

dnl AC_ASSERT_OCAML_PKG([pkg_name], [pkg_version])
dnl
dnl fails if $pkg_name is not installed; also fails if it is not
dnl installed at version $pkg_version if specified
dnl
dnl assumes that AC_PROG_FINDLIB has been called
AC_DEFUN([AC_ASSERT_OCAML_PKG],
[dnl
  AC_CHECK_OCAML_PKG_PATH([$1], [$2], [$3])

  unset has_pkg
  unset pkg
  unset version

  AS_IF([test "$OCAMLFIND" = "no"], [dnl
    # trick to detect if ocamlfind is correctly installed and give the
    # right opam instructions to install it if not since they're the
    # same as when any other opam package is missing.
    has_pkg=no
    pkg=ocamlfind
    version=
  ], [dnl
    has_pkg=$AS_TR_SH[OCAML_PKG_$1]
    pkg=$1
    version=
    AS_IF([test "x$3" != "x"], [dnl
      version=" version $3"
    ])
  ])
  AS_IF([test "$has_pkg" = "no"], [dnl
    AC_MSG_ERROR([missing OCaml dependency: $pkg$version

If you are using opam, please run

  opam update
  opam install --deps-only infer .])
  ])
])