X-Git-Url: https://git.hcoop.net/hcoop/domtool2.git/blobdiff_plain/9b7ee2b22abce813120a633f5a4f5523a630a2ea..a7951e95f170a9e3534e8b36787a5af1d353156f:/src/describe.sml

diff --git a/src/describe.sml b/src/describe.sml
index 1384d3b..11194af 100644
--- a/src/describe.sml
+++ b/src/describe.sml
@@ -102,7 +102,32 @@ fun describe_unification_error t ue =
 	     print " in:\n";
 	     output (p_typ t))
 
-fun describe_type_error loc te =
+fun will_be_action (t, _) =
+    case t of
+	TArrow (_, t') => will_be_action t'
+      | TAction _ => true
+      | TNested _ => true
+      | TUnif (_, ref (SOME t')) => will_be_action t'
+      | _ => false
+
+fun get_first_arg (t, _) =
+    case t of
+	TArrow (t', _) => t'
+      | TUnif (_, ref (SOME t')) => get_first_arg t'
+      | _ => raise Fail "get_first_arg failed!"
+
+fun hint te =
+    case te of
+	WrongType (_, _, (TBase "string", _), (TBase "your_domain", _), _) =>
+	SOME "Did you forget to request permission to configure this domain?  See:\n\thttps://members.hcoop.net/portal/domain"
+      | WrongType (_, (EString dom, _), (TBase "string", _), (TBase "domain", _), _) =>
+	if CharVector.exists Char.isUpper dom then
+	    SOME "Uppercase letters aren't allowed in domain strings."
+	else
+	    NONE
+      | _ => NONE
+
+fun describe_type_error' loc te =
     case te of
 	WrongType (place, e, t1, t2, ueo) =>
 	(ErrorMsg.error (SOME loc) (place ^ " has wrong type.");
@@ -111,10 +136,15 @@ fun describe_type_error loc te =
 	 preface ("Needed type:", p_typ t2);
 	 Option.app (describe_unification_error t1) ueo)
       |	WrongForm (place, form, e, t, ueo) =>
-	(ErrorMsg.error (SOME loc) (place ^ " has a non-" ^ form ^ " type.");
-	 preface ("Expression:", p_exp e);
-	 preface ("      Type:", p_typ t);
-	 Option.app (describe_unification_error t) ueo)
+	if form = "action" andalso will_be_action t then
+	    (ErrorMsg.error (SOME loc) ("Not enough arguments passed to configuration function. (" ^ place ^ ")");
+	     preface (" Expression so far:", p_exp e);
+	     preface ("Next argument type:", p_typ (get_first_arg t)))
+	else
+	    (ErrorMsg.error (SOME loc) (place ^ " has a non-" ^ form ^ " type.");
+	     preface ("Expression:", p_exp e);
+	     preface ("      Type:", p_typ t);
+	     Option.app (describe_unification_error t) ueo)
       | UnboundVariable name =>
 	ErrorMsg.error (SOME loc) ("Unbound variable " ^ name ^ ".\n")
       |	WrongPred (place, p1, p2) =>
@@ -122,4 +152,29 @@ fun describe_type_error loc te =
 	 preface ("Have:", p_pred p1);
 	 preface ("Need:", p_pred p2))
 
+fun ununify (tAll as (t, _)) =
+    case t of
+	TUnif (_, ref (SOME t)) => ununify t
+      | _ => tAll
+
+fun normalize_error err =
+    case err of
+	WrongType (s, e, t1, t2, ueo) =>
+	WrongType (s, e, ununify t1, ununify t2, ueo)
+      | WrongForm (s1, s2, e, t, ueo) =>
+	WrongForm (s1, s2, e, ununify t, ueo)
+      | UnboundVariable _ => err
+      | WrongPred _ => err
+
+fun describe_type_error loc te =
+    let
+	val te = normalize_error te
+    in
+	describe_type_error' loc te;
+	Option.app (fn s => (print "Hint Monster says:\n";
+			     print s;
+			     print "\n"))
+		   (hint te)
+    end
+
 end