NONE => raise Fail ("Unavailable environment variable " ^ name)
| SOME e =>
case arg e of
- NONE => raise Fail ("Bad format for environment variable " ^ name)
+ NONE => (Print.preface ("Unexpected value for " ^ name ^ ":",
+ Print.p_exp e);
+ raise Fail ("Bad format for environment variable " ^ name))
| SOME v => v
fun type_one func arg f =