<!-- $MDX env=official -->
```ocaml
# #use "../local-install/lib/ocaml/topfind.camlp5";;
- : unit = ()
Findlib has been successfully loaded. Additional directives:
  #require "package";;      to load a package
  #list;;                   to list the available packages
  #camlp4o;;                to load camlp4 (standard syntax)
  #camlp4r;;                to load camlp4 (revised syntax)
  #predicates "p,q,...";;   to set these predicates
  Topfind.reset();;         to force that packages will be reloaded
  #thread;;                 to enable threads

- : unit = ()
Additional Camlp5 directives:
  #camlp5o;;                to load camlp5 (standard syntax)
  #camlp5r;;                to load camlp5 (revised syntax)

- : unit = ()
# #camlp5o ;;
# let exc_converter = function
    Exit as exc ->
    let s = Printexc.to_string exc in
    Some (Location.error s)
  | _ -> None
val exc_converter : exn -> Location.report option = <fun>
# Location.register_error_of_exn exc_converter ;;
- : unit = ()
```

<!-- $MDX env=official -->
```ocaml
# let x = 1 ;;
val x : int = 1
```

```sh
$ ocaml < fixtures/official_toplevel_linedir1.ml

#   File "fixtures/q.ml", line 10, characters 6-7:
Error: Syntax error
#
```

```sh
$ ocaml < fixtures/official_toplevel_linedir2.ml

# - : unit = ()
Findlib has been successfully loaded. Additional directives:
  #require "package";;      to load a package
  #list;;                   to list the available packages
  #camlp4o;;                to load camlp4 (standard syntax)
  #camlp4r;;                to load camlp4 (revised syntax)
  #predicates "p,q,...";;   to set these predicates
  Topfind.reset();;         to force that packages will be reloaded
  #thread;;                 to enable threads

- : unit = ()
Additional Camlp5 directives:
  #camlp5o;;                to load camlp5 (standard syntax)
  #camlp5r;;                to load camlp5 (revised syntax)

- : unit = ()
	Camlp5 parsing version (OCaml) 8.05.02

#   Toplevel input:
# # 10 "fixtures/r.ml"
  let _ _ = 1 ;;
      ^
Failure: this is not a constructor, it cannot be applied in a pattern
#
```

```sh
$ ocaml < fixtures/official_toplevel_linedir1use.ml

#   File "fixtures/s.ml", line 10, characters 6-7:
Error: Syntax error
#
```

```sh
$ ocaml < fixtures/official_toplevel_linedir2use.ml

# - : unit = ()
Findlib has been successfully loaded. Additional directives:
  #require "package";;      to load a package
  #list;;                   to list the available packages
  #camlp4o;;                to load camlp4 (standard syntax)
  #camlp4r;;                to load camlp4 (revised syntax)
  #predicates "p,q,...";;   to set these predicates
  Topfind.reset();;         to force that packages will be reloaded
  #thread;;                 to enable threads

- : unit = ()
Additional Camlp5 directives:
  #camlp5o;;                to load camlp5 (standard syntax)
  #camlp5r;;                to load camlp5 (revised syntax)

- : unit = ()
	Camlp5 parsing version (OCaml) 8.05.02

#   File "fixtures/s.ml", line 10, characters 4-5:
Failure: this is not a constructor, it cannot be applied in a pattern
#
```
