1 files changed, 131 insertions, 0 deletions
diff --git a/omegalib/omega_lib/src/pres_rear.cc b/omegalib/omega_lib/src/pres_rear.cc
new file mode 100644
index 0000000..508959d
--- /dev/null
+++ b/omegalib/omega_lib/src/pres_rear.cc
@@ -0,0 +1,131 @@
+#include <omega/pres_tree.h>
+#include <omega/pres_conj.h>
+#include <omega/Relation.h>
+#include <omega/omega_i.h>
+
+namespace omega {
+
+/////////////////////////
+//                     //
+// Rearrange functions //
+//                     //
+/////////////////////////
+
+//
+// Rules:
+// ~ (f1 | f2 | ... | fn) = ~f1 & ~f2 & ... & fn
+// ~ ~ f = f
+// Forall v: f = ~ (Exists v: ~ f)
+// Exists v: (f1 | ... | fn) = (Exists v: f1) | ... | (Exists v: fn)
+//
+
+void Rel_Body::rearrange() {
+  assert(children().length()==1);
+
+  skip_finalization_check++;
+  formula()->rearrange();
+  skip_finalization_check--;
+
+  if(pres_debug) {
+    fprintf(DebugFile, "\n=== Rearranged TREE ===\n");
+    prefix_print(DebugFile);
+  }
+}
+
+void Formula::rearrange() {
+  // copy list of children, as they may be removed as we work
+  List<Formula*> kiddies = myChildren;
+
+  for(List_Iterator<Formula*> c(kiddies); c; c++)
+    (*c)->rearrange();
+}
+
+//
+// Push nots down the tree until quantifier or conjunct, rearrange kids
+//
+void F_Not::rearrange() {
+  Formula *child = children().front();
+  Formula *new_child, *f;
+
+  switch(child->node_type()) {
+  case Op_Or:
+    parent().remove_child(this);
+    new_child = parent().add_and();
+    while(!child->children().empty()) {
+      f = child->children().remove_front(); 
+      F_Not *new_not = new_child->add_not(); 
+      new_not->add_child(f); 
+    }
+    delete this;
+    break;
+//case Op_And:
+//  parent().remove_child(this);
+//  new_child = parent().add_or();
+//  while(!child->myChildren.empty()) {
+//    f = child->myChildren.remove_front(); 
+//    F_Not *new_not = new_child->add_not(); 
+//    new_not->add_child(f); 
+//  }
+//  delete this;
+//  break;
+  case Op_Not:
+    parent().remove_child(this);
+    f = child->children().remove_front(); 
+    parent().add_child(f);
+    delete this;
+    f->rearrange();
+    return;
+  default:
+    new_child = child;
+    break;
+  }
+
+  new_child->rearrange();
+}
+ 
+//
+// Convert a universal quantifier to "not exists not".
+// Forall v: f = ~ (Exists v: ~ f)
+//
+void F_Forall::rearrange() {
+  Formula &p = parent();
+  p.remove_child(this);
+  
+  F_Not *topnot = p.add_not();
+  F_Exists *exist = topnot->add_exists();
+  for (Variable_ID_Iterator VI(myLocals); VI; VI++)
+    (*VI)->set_kind(Exists_Var);
+  exist->myLocals.join(myLocals);
+
+  F_Not *botnot = exist->add_not();
+  Formula *f = children().remove_front();
+  botnot->add_child(f);
+
+  delete this;
+
+  botnot->rearrange();
+}
+
+//
+// Exists v: (f1 | ... | fn) = (Exists v: f1) | ... | (Exists v: fn)
+//
+void F_Exists::rearrange() {
+  Formula* child = children().front();
+  switch(child->node_type()) {
+  case Op_Or:
+  case Op_Conjunct:
+  case Op_Exists:
+    child->push_exists(myLocals);
+    parent().remove_child(this);
+    parent().add_child(child);
+    children().remove_front();
+    delete this;
+    break;
+  default:
+    break;
+  }
+
+  child->rearrange();
+}
+
+} // namespace