Tidy up handling of unimplemented features. These are expected (if undesirable) sorts of error, we should handle better than "backtrace and exit 2".

2 files changed, 33 insertions, 4 deletions

diff --git a/src/boot/driver/main.ml b/src/boot/driver/main.ml
index 9cb068ef..cef66f77 100644
--- a/src/boot/driver/main.ml
+++ b/src/boot/driver/main.ml
@@ -238,7 +238,7 @@ let _ =
 ;;
 
 
-let (crate:Ast.crate) =
+let parse_input_crate _ : Ast.crate =
   Session.time_inner "parse" sess
     begin
       fun _ ->
@@ -292,6 +292,15 @@ let (crate:Ast.crate) =
     end
 ;;
 
+let (crate:Ast.crate) =
+  try
+    parse_input_crate()
+  with
+      Not_implemented (ido, str) ->
+        Session.report_err sess ido str;
+        { node = Ast.empty_crate'; id = Common.Node 0 }
+;;
+
 exit_if_failed ()
 ;;
 
@@ -399,9 +408,16 @@ let main_pipeline _ =
           exit_if_failed ()
 ;;
 
-if sess.Session.sess_alt_backend
-then Glue.alt_pipeline sess sem_cx crate
-else main_pipeline ()
+try
+  if sess.Session.sess_alt_backend
+  then Glue.alt_pipeline sess sem_cx crate
+  else main_pipeline ()
+with
+    Not_implemented (ido, str) ->
+      Session.report_err sess ido str
+;;
+
+exit_if_failed ()
 ;;
 
 if sess.Session.sess_report_timing
diff --git a/src/boot/driver/session.ml b/src/boot/driver/session.ml
index 80253f44..210dd7be 100644
--- a/src/boot/driver/session.ml
+++ b/src/boot/driver/session.ml
@@ -101,6 +101,19 @@ let filename_of (fo:filename option) : filename =
     | Some f -> f
 ;;
 
+let report_err sess ido str =
+  let spano = match ido with
+      None -> None
+    | Some id -> get_span sess id
+  in
+    match spano with
+        None ->
+          fail sess "Error: %s\n%!" str
+      | Some span ->
+          fail sess "%s:E:Error: %s\n%!"
+            (string_of_span span) str
+;;
+
 (*
  * Local Variables:
  * fill-column: 78;