From: Mark Thom <markjordanthom@gmail.com>
Date: Sat, 15 Jan 2022 18:03:41 +0000 (-0700)
Subject: deduplicate but do not sort anonymous variables in toplevel (#1196)
X-Git-Tag: v0.9.0^2~64
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=83378e4373b73e4cfc4266b1920d14517ffe984a;p=scryer-prolog.git

deduplicate but do not sort anonymous variables in toplevel (#1196)
---

diff --git a/src/machine/system_calls.rs b/src/machine/system_calls.rs
index 6163a467..67611cc5 100644
--- a/src/machine/system_calls.rs
+++ b/src/machine/system_calls.rs
@@ -555,7 +555,7 @@ impl MachineState {
         let outcome = heap_loc_as_cell!(
             iter_to_heap_list(
                 &mut self.heap,
-                seen_set.into_iter().rev(),
+                seen_set.into_iter(),
             )
         );
 
diff --git a/src/toplevel.pl b/src/toplevel.pl
index b72e0ed1..27783c45 100644
--- a/src/toplevel.pl
+++ b/src/toplevel.pl
@@ -292,7 +292,7 @@ write_eqs_and_read_input(B, VarList) :-
     % one layer of depth added for (=/2) functor
     maplist(\Term^Vs^term_variables_under_max_depth(Term, 22, Vs), Equations, EquationVars),
     append([AttrGoalVars | EquationVars], Vars1),
-    sort(Vars1, Vars2),
+    term_variables(Vars1, Vars2), % deduplicate vars of Vars1 but preserve their order.
     charsio:extend_var_list(Vars2, VarList, NewVarList0, fabricated),
     (   bb_get('$first_answer', true) ->
         write('   '),