X-Git-Url: https://git.hcoop.net/hcoop/domtool2.git/blobdiff_plain/cf879b4f037242eb535207f0ff3400fe89ab61b1..3f84c976dad19bd32d8b4043e3da2d074e9fac40:/src/env.sml

diff --git a/src/env.sml b/src/env.sml
index f87278f..edb1ffd 100644
--- a/src/env.sml
+++ b/src/env.sml
@@ -170,7 +170,9 @@ fun env arg (evs, name) =
 	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 =