From 83ead46e13ace9076e1c5de22242b4f9fae9debf Mon Sep 17 00:00:00 2001
From: Mark Thom <markjordanthom@gmail.com>
Date: Mon, 14 Oct 2019 00:07:22 -0600
Subject: [PATCH] re: issue #196

---
 src/prolog/machine/attributed_variables.rs |  3 ++
 src/prolog/machine/project_attributes.pl   | 32 +++++++++++++++-------
 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/src/prolog/machine/attributed_variables.rs b/src/prolog/machine/attributed_variables.rs
index d3ad71d0..41189fad 100644
--- a/src/prolog/machine/attributed_variables.rs
+++ b/src/prolog/machine/attributed_variables.rs
@@ -111,6 +111,9 @@ impl MachineState {
                     HeapCellValue::Addr(Addr::StackCell(fr, sc)) => {
                         query_vars.insert(Addr::StackCell(fr, sc));
                     }
+                    HeapCellValue::Addr(Addr::AttrVar(h)) => {
+                        query_vars.insert(Addr::AttrVar(h));
+                    }
                     _ => {}
                 };
             }
diff --git a/src/prolog/machine/project_attributes.pl b/src/prolog/machine/project_attributes.pl
index 084d60b8..3b399f98 100644
--- a/src/prolog/machine/project_attributes.pl
+++ b/src/prolog/machine/project_attributes.pl
@@ -2,8 +2,8 @@ driver(QueryVars, AttrVars) :-
     gather_modules(AttrVars, Modules0, _),
     sort(Modules0, Modules),
     call_project_attributes(Modules, QueryVars, AttrVars),
-    call_attribute_goals(Modules, QueryVars),
-    call_attribute_goals(Modules, AttrVars),
+    call_attribute_goals(Modules, call_query_var_goals, QueryVars),
+    call_attribute_goals(Modules, call_attr_var_goals, AttrVars),
     '$return_from_attribute_goals'.
 
 enqueue_goals(Goals0) :-
@@ -27,17 +27,18 @@ call_project_attributes([], _, _).
 call_project_attributes([Module|Modules], QueryVars, AttrVars) :-
     (   catch(Module:project_attributes(QueryVars, AttrVars),
 	      E,
-	      '$print_project_attributes_exception'(Module, E))
+	      '$print_project_attributes_exception'(Module, E)
+	     )
     ->  true
     ;   true
     ),
     call_project_attributes(Modules, QueryVars, AttrVars).
 
-call_attribute_goals([], _).
-call_attribute_goals([Module | Modules], AttrVars) :-
-    call_goals(AttrVars, Module, Goals),
+call_attribute_goals([], _, _).
+call_attribute_goals([Module | Modules], GoalCaller, AttrVars) :-
+    call(GoalCaller, AttrVars, Module, Goals),
     enqueue_goals(Goals),
-    call_attribute_goals(Modules, AttrVars).
+    call_attribute_goals(Modules, GoalCaller, AttrVars).
 
 '$print_attribute_goals_exception'(Module, E) :-
     (  E = error(evaluation_error((Module:attribute_goals)/3), attribute_goals/3)
@@ -47,8 +48,8 @@ call_attribute_goals([Module | Modules], AttrVars) :-
        nl
     ).
 
-call_goals([], _, []).
-call_goals([AttrVar|AttrVars], Module, Goals) :-
+call_query_var_goals([], _, []).
+call_query_var_goals([AttrVar|AttrVars], Module, Goals) :-
     (  catch((  Module:attribute_goals(AttrVar, Goals, RGoals0),
 	        atts:'$default_attr_list'(Module, AttrVar, RGoals0, RGoals)
 	     ),
@@ -59,7 +60,18 @@ call_goals([AttrVar|AttrVars], Module, Goals) :-
     -> true
     ;  atts:'$default_attr_list'(Module, AttrVar, Goals, RGoals)
     ),
-    call_goals(AttrVars, Module, RGoals).
+    call_query_var_goals(AttrVars, Module, RGoals).
+
+call_attr_var_goals([], _, []).
+call_attr_var_goals([AttrVar|AttrVars], Module, Goals) :-
+    (  catch(Module:attribute_goals(AttrVar, Goals, RGoals),	        	     
+	     E,
+	     '$print_attribute_goals_exception'(Module, E)
+	     )
+    -> true
+    ;  true
+    ),
+    call_attr_var_goals(AttrVars, Module, RGoals).
 
 gather_modules([], [], _).
 gather_modules([AttrVar|AttrVars], Modules, Modules0) :-
-- 
2.54.0