made understandable again

conditions/football.c

@@ -134,31 +134,12 @@ static boolean advance_substitution(void)
   return result;
 }
 
-/* Try to solve in solve_nr_remaining half-moves.
- * @param si slice index
- * @note assigns solve_result the length of solution found and written, i.e.:
- *            previous_move_is_illegal the move just played is illegal
- *            this_move_is_illegal     the move being played is illegal
- *            immobility_on_next_move  the moves just played led to an
- *                                     unintended immobility on the next move
- *            <=n+1 length of shortest solution found (n+1 only if in next
- *                                     branch)
- *            n+2 no solution found in this branch
- *            n+3 no solution found in next branch
- *            (with n denominating solve_nr_remaining)
- */
-void football_chess_substitutor_solve(slice_index si)
+static void try_current_substitute(slice_index si)
 {
   TraceFunctionEntry(__func__);
   TraceFunctionParam("%u",si);
   TraceFunctionParamListEnd();
 
-  if (!post_move_am_i_iterating())
-    init_substitution();
-
-  if (current_football_substitution[nbply]==Empty)
-    pipe_solve_delegate(si);
-  else
   {
     move_effect_journal_index_type const base = move_effect_journal_base[nbply];
     move_effect_journal_index_type const movement = base+move_effect_journal_index_offset_movement;
@@ -183,6 +164,44 @@ void football_chess_substitutor_solve(slice_index si)
   TraceFunctionResultEnd();
 }
 
+/* Try to solve in solve_nr_remaining half-moves.
+ * @param si slice index
+ * @note assigns solve_result the length of solution found and written, i.e.:
+ *            previous_move_is_illegal the move just played is illegal
+ *            this_move_is_illegal     the move being played is illegal
+ *            immobility_on_next_move  the moves just played led to an
+ *                                     unintended immobility on the next move
+ *            <=n+1 length of shortest solution found (n+1 only if in next
+ *                                     branch)
+ *            n+2 no solution found in this branch
+ *            n+3 no solution found in next branch
+ *            (with n denominating solve_nr_remaining)
+ */
+void football_chess_substitutor_solve(slice_index si)
+{
+  TraceFunctionEntry(__func__);
+  TraceFunctionParam("%u",si);
+  TraceFunctionParamListEnd();
+
+  if (!post_move_am_i_iterating())
+  {
+    init_substitution();
+    if (current_football_substitution[nbply]==Empty)
+    {
+      post_move_iteration_solve_delegate(si);
+      if (!post_move_iteration_is_locked())
+        post_move_iteration_end();
+    }
+    else
+      try_current_substitute(si);
+  }
+  else
+    try_current_substitute(si);
+
+  TraceFunctionExit(__func__);
+  TraceFunctionResultEnd();
+}
+
 /* Instrument slices with promotee markers
  */
 void solving_insert_football_chess(slice_index si)