diff --git a/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/unification.mps b/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/unification.mps
index 08029da1..52b63acc 100644
--- a/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/unification.mps
+++ b/languages/jetbrains.mps.logic/runtime/models/jetbrains/mps/logic/builtin/unification.mps
@@ -803,8 +803,8 @@
             <node concept="3cpWs8" id="1Ns6gpY7SoW" role="3cqZAp">
               <node concept="3cpWsn" id="1Ns6gpY7SoX" role="3cpWs9">
                 <property role="TrG5h" value="bvar" />
-                <node concept="3uibUv" id="1Ns6gpY7SoU" role="1tU5fm">
-                  <ref role="3uigEE" to="jfki:~Var" resolve="Var" />
+                <node concept="3uibUv" id="56MMu0Aqrrr" role="1tU5fm">
+                  <ref role="3uigEE" to="jfki:~Node" resolve="Node" />
                 </node>
                 <node concept="2OqwBi" id="1Ns6gpY7SoY" role="33vP2m">
                   <node concept="37vLTw" id="1Ns6gpY7SoZ" role="2Oq$k0">
@@ -914,8 +914,12 @@
                         <ref role="37wK5l" to="jfki:~Substitution.Binding.node()" resolve="node" />
                       </node>
                     </node>
-                    <node concept="liA8E" id="6SkxsMzEqaD" role="2OqNvi">
-                      <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+                    <node concept="liA8E" id="56MMu0Ap5n2" role="2OqNvi">
+                      <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                      <node concept="Rm8GO" id="56MMu0Ap5n3" role="37wK5m">
+                        <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                        <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                      </node>
                     </node>
                   </node>
                   <node concept="3eNFk2" id="6SkxsMzEv3z" role="3eNLev">
@@ -928,28 +932,27 @@
                           <ref role="37wK5l" to="jfki:~Substitution.Binding.node()" resolve="node" />
                         </node>
                       </node>
-                      <node concept="liA8E" id="6SkxsMzEvgy" role="2OqNvi">
-                        <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                      <node concept="liA8E" id="56MMu0ApUkU" role="2OqNvi">
+                        <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                        <node concept="Rm8GO" id="56MMu0ApUkV" role="37wK5m">
+                          <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                          <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                        </node>
                       </node>
                     </node>
                     <node concept="3clFbS" id="6SkxsMzEv3_" role="3eOfB_">
                       <node concept="3cpWs8" id="1Ns6gpY7VW1" role="3cqZAp">
                         <node concept="3cpWsn" id="1Ns6gpY7VW2" role="3cpWs9">
                           <property role="TrG5h" value="nvar" />
-                          <node concept="3uibUv" id="1Ns6gpY7VW0" role="1tU5fm">
-                            <ref role="3uigEE" to="jfki:~Var" resolve="Var" />
+                          <node concept="3uibUv" id="56MMu0Aqrmr" role="1tU5fm">
+                            <ref role="3uigEE" to="jfki:~Node" resolve="Node" />
                           </node>
-                          <node concept="2OqwBi" id="1Ns6gpY7VW3" role="33vP2m">
-                            <node concept="2OqwBi" id="1Ns6gpY7VW4" role="2Oq$k0">
-                              <node concept="37vLTw" id="1Ns6gpY7VW5" role="2Oq$k0">
-                                <ref role="3cqZAo" node="6SkxsMzDp28" resolve="bnd" />
-                              </node>
-                              <node concept="liA8E" id="1Ns6gpY7VW6" role="2OqNvi">
-                                <ref role="37wK5l" to="jfki:~Substitution.Binding.node()" resolve="node" />
-                              </node>
+                          <node concept="2OqwBi" id="1Ns6gpY7VW4" role="33vP2m">
+                            <node concept="37vLTw" id="1Ns6gpY7VW5" role="2Oq$k0">
+                              <ref role="3cqZAo" node="6SkxsMzDp28" resolve="bnd" />
                             </node>
-                            <node concept="liA8E" id="1Ns6gpY7VW7" role="2OqNvi">
-                              <ref role="37wK5l" to="jfki:~Node.asVar()" resolve="asVar" />
+                            <node concept="liA8E" id="1Ns6gpY7VW6" role="2OqNvi">
+                              <ref role="37wK5l" to="jfki:~Substitution.Binding.node()" resolve="node" />
                             </node>
                           </node>
                         </node>
@@ -1043,23 +1046,18 @@
                 <node concept="3clFbS" id="5p8T3QHDoXj" role="3eOfB_">
                   <node concept="3clFbJ" id="5p8T3QHDAFU" role="3cqZAp">
                     <node concept="3clFbS" id="5p8T3QHDAFW" role="3clFbx">
-                      <node concept="3cpWs8" id="5p8T3QHGX$v" role="3cqZAp">
-                        <node concept="3cpWsn" id="5p8T3QHGX$w" role="3cpWs9">
+                      <node concept="3cpWs8" id="56MMu0AoNE1" role="3cqZAp">
+                        <node concept="3cpWsn" id="56MMu0AoNE2" role="3cpWs9">
                           <property role="TrG5h" value="nterm" />
-                          <node concept="3uibUv" id="5p8T3QHGX$u" role="1tU5fm">
-                            <ref role="3uigEE" to="jfki:~Term" resolve="Term" />
+                          <node concept="3uibUv" id="56MMu0AoNDZ" role="1tU5fm">
+                            <ref role="3uigEE" to="jfki:~Node" resolve="Node" />
                           </node>
-                          <node concept="2OqwBi" id="5p8T3QHGX$x" role="33vP2m">
-                            <node concept="2OqwBi" id="5p8T3QHGX$y" role="2Oq$k0">
-                              <node concept="37vLTw" id="5p8T3QHGX$z" role="2Oq$k0">
-                                <ref role="3cqZAo" node="6SkxsMzDp28" resolve="bnd" />
-                              </node>
-                              <node concept="liA8E" id="5p8T3QHGX$$" role="2OqNvi">
-                                <ref role="37wK5l" to="jfki:~Substitution.Binding.node()" resolve="node" />
-                              </node>
+                          <node concept="2OqwBi" id="56MMu0AoNE3" role="33vP2m">
+                            <node concept="37vLTw" id="56MMu0AoNE4" role="2Oq$k0">
+                              <ref role="3cqZAo" node="6SkxsMzDp28" resolve="bnd" />
                             </node>
-                            <node concept="liA8E" id="5p8T3QHGX$_" role="2OqNvi">
-                              <ref role="37wK5l" to="jfki:~Node.asTerm()" resolve="asTerm" />
+                            <node concept="liA8E" id="56MMu0AoNE5" role="2OqNvi">
+                              <ref role="37wK5l" to="jfki:~Substitution.Binding.node()" resolve="node" />
                             </node>
                           </node>
                         </node>
@@ -1079,10 +1077,10 @@
                                 <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
                                 <node concept="2OqwBi" id="5p8T3QHGZ1m" role="37wK5m">
                                   <node concept="37vLTw" id="5p8T3QHGZ1n" role="2Oq$k0">
-                                    <ref role="3cqZAo" node="5p8T3QHGX$w" resolve="nterm" />
+                                    <ref role="3cqZAo" node="56MMu0AoNE2" resolve="nterm" />
                                   </node>
                                   <node concept="liA8E" id="5p8T3QHGZ1o" role="2OqNvi">
-                                    <ref role="37wK5l" to="jfki:~Term.symbol()" resolve="symbol" />
+                                    <ref role="37wK5l" to="jfki:~Node.symbol()" resolve="symbol" />
                                   </node>
                                 </node>
                               </node>
@@ -1130,7 +1128,11 @@
                         </node>
                       </node>
                       <node concept="liA8E" id="5p8T3QHDB81" role="2OqNvi">
-                        <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+                        <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                        <node concept="Rm8GO" id="56MMu0AoMUp" role="37wK5m">
+                          <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                          <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                        </node>
                       </node>
                     </node>
                     <node concept="3eNFk2" id="5p8T3QHDB8O" role="3eNLev">
@@ -1143,28 +1145,27 @@
                             <ref role="37wK5l" to="jfki:~Substitution.Binding.node()" resolve="node" />
                           </node>
                         </node>
-                        <node concept="liA8E" id="5p8T3QHDBu$" role="2OqNvi">
-                          <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                        <node concept="liA8E" id="56MMu0ApUmr" role="2OqNvi">
+                          <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                          <node concept="Rm8GO" id="56MMu0ApUms" role="37wK5m">
+                            <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                            <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                          </node>
                         </node>
                       </node>
                       <node concept="3clFbS" id="5p8T3QHDB8Q" role="3eOfB_">
                         <node concept="3cpWs8" id="5p8T3QHDBTm" role="3cqZAp">
                           <node concept="3cpWsn" id="5p8T3QHDBTn" role="3cpWs9">
                             <property role="TrG5h" value="nvar" />
-                            <node concept="3uibUv" id="5p8T3QHDBQ4" role="1tU5fm">
-                              <ref role="3uigEE" to="jfki:~Var" resolve="Var" />
+                            <node concept="3uibUv" id="56MMu0AqrCf" role="1tU5fm">
+                              <ref role="3uigEE" to="jfki:~Node" resolve="Node" />
                             </node>
-                            <node concept="2OqwBi" id="5p8T3QHDBTo" role="33vP2m">
-                              <node concept="2OqwBi" id="5p8T3QHDBTp" role="2Oq$k0">
-                                <node concept="37vLTw" id="5p8T3QHDBTq" role="2Oq$k0">
-                                  <ref role="3cqZAo" node="6SkxsMzDp28" resolve="bnd" />
-                                </node>
-                                <node concept="liA8E" id="5p8T3QHDBTr" role="2OqNvi">
-                                  <ref role="37wK5l" to="jfki:~Substitution.Binding.node()" resolve="node" />
-                                </node>
+                            <node concept="2OqwBi" id="5p8T3QHDBTp" role="33vP2m">
+                              <node concept="37vLTw" id="5p8T3QHDBTq" role="2Oq$k0">
+                                <ref role="3cqZAo" node="6SkxsMzDp28" resolve="bnd" />
                               </node>
-                              <node concept="liA8E" id="5p8T3QHDBTs" role="2OqNvi">
-                                <ref role="37wK5l" to="jfki:~Node.asVar()" resolve="asVar" />
+                              <node concept="liA8E" id="5p8T3QHDBTr" role="2OqNvi">
+                                <ref role="37wK5l" to="jfki:~Substitution.Binding.node()" resolve="node" />
                               </node>
                             </node>
                           </node>
@@ -2738,8 +2739,12 @@
             <node concept="37vLTw" id="6xYPVrpAeuZ" role="2Oq$k0">
               <ref role="3cqZAo" node="6xYPVrp$v6t" resolve="node" />
             </node>
-            <node concept="liA8E" id="6xYPVrpAgn2" role="2OqNvi">
-              <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+            <node concept="liA8E" id="56MMu0Ap5oY" role="2OqNvi">
+              <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+              <node concept="Rm8GO" id="56MMu0Ap5oZ" role="37wK5m">
+                <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+              </node>
             </node>
           </node>
           <node concept="3eNFk2" id="6xYPVrpAgRc" role="3eNLev">
@@ -2778,8 +2783,12 @@
               <node concept="37vLTw" id="6xYPVrpAiyh" role="2Oq$k0">
                 <ref role="3cqZAo" node="6xYPVrp$v6t" resolve="node" />
               </node>
-              <node concept="liA8E" id="6xYPVrpAklO" role="2OqNvi">
-                <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+              <node concept="liA8E" id="56MMu0ApUC5" role="2OqNvi">
+                <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                <node concept="Rm8GO" id="56MMu0ApUC6" role="37wK5m">
+                  <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                  <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                </node>
               </node>
             </node>
           </node>
@@ -2833,8 +2842,12 @@
             <node concept="37vLTw" id="6xYPVrpAspT" role="2Oq$k0">
               <ref role="3cqZAo" node="6xYPVrpA0lw" resolve="node" />
             </node>
-            <node concept="liA8E" id="6xYPVrpAuju" role="2OqNvi">
-              <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+            <node concept="liA8E" id="56MMu0Ap1Z2" role="2OqNvi">
+              <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+              <node concept="Rm8GO" id="56MMu0Ap21O" role="37wK5m">
+                <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+              </node>
             </node>
           </node>
           <node concept="3clFbS" id="6xYPVrpA0lR" role="3clFbx">
@@ -2851,16 +2864,11 @@
                       <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
                       <ref role="37wK5l" to="e2lb:~String.valueOf(java.lang.Object):java.lang.String" resolve="valueOf" />
                       <node concept="2OqwBi" id="6xYPVrpAEDK" role="37wK5m">
-                        <node concept="2OqwBi" id="6xYPVrpAG$0" role="2Oq$k0">
-                          <node concept="37vLTw" id="6xYPVrpAGy_" role="2Oq$k0">
-                            <ref role="3cqZAo" node="6xYPVrpA0lw" resolve="node" />
-                          </node>
-                          <node concept="liA8E" id="6xYPVrpAGKP" role="2OqNvi">
-                            <ref role="37wK5l" to="jfki:~Node.asTerm()" resolve="asTerm" />
-                          </node>
+                        <node concept="37vLTw" id="6xYPVrpAGy_" role="2Oq$k0">
+                          <ref role="3cqZAo" node="6xYPVrpA0lw" resolve="node" />
                         </node>
                         <node concept="liA8E" id="6xYPVrpAEDM" role="2OqNvi">
-                          <ref role="37wK5l" to="jfki:~Term.symbol()" resolve="symbol" />
+                          <ref role="37wK5l" to="jfki:~Node.symbol()" resolve="symbol" />
                         </node>
                       </node>
                     </node>
@@ -2952,8 +2960,12 @@
               <node concept="37vLTw" id="6xYPVrpAww9" role="2Oq$k0">
                 <ref role="3cqZAo" node="6xYPVrpA0lw" resolve="node" />
               </node>
-              <node concept="liA8E" id="6xYPVrpAxJU" role="2OqNvi">
-                <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+              <node concept="liA8E" id="56MMu0ApUht" role="2OqNvi">
+                <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                <node concept="Rm8GO" id="56MMu0ApUjt" role="37wK5m">
+                  <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                </node>
               </node>
             </node>
           </node>
diff --git a/solutions/jetbrains.mps.type.solver/models/jetbrains/mps/type/inference/baseLanguage.mps b/solutions/jetbrains.mps.type.solver/models/jetbrains/mps/type/inference/baseLanguage.mps
index 9d2e408a..fb9f957b 100644
--- a/solutions/jetbrains.mps.type.solver/models/jetbrains/mps/type/inference/baseLanguage.mps
+++ b/solutions/jetbrains.mps.type.solver/models/jetbrains/mps/type/inference/baseLanguage.mps
@@ -740,8 +740,8 @@
                         <ref role="37wK5l" to="jfki:~Substitution.Binding.var()" resolve="var" />
                       </node>
                     </node>
-                    <node concept="liA8E" id="3JgCwkqBAVm" role="2OqNvi">
-                      <ref role="37wK5l" to="jfki:~Var.name()" resolve="name" />
+                    <node concept="liA8E" id="56MMu0Aw8Ta" role="2OqNvi">
+                      <ref role="37wK5l" to="jfki:~Node.symbol()" resolve="symbol" />
                     </node>
                   </node>
                 </node>
diff --git a/solutions/jetbrains.mps.type.solver/models/jetbrains/mps/type/inference/common.mps b/solutions/jetbrains.mps.type.solver/models/jetbrains/mps/type/inference/common.mps
index 9e3893ba..6bc0c0fb 100644
--- a/solutions/jetbrains.mps.type.solver/models/jetbrains/mps/type/inference/common.mps
+++ b/solutions/jetbrains.mps.type.solver/models/jetbrains/mps/type/inference/common.mps
@@ -175,7 +175,7 @@
       </concept>
     </language>
     <language id="35320f26-77cb-4c55-be9f-a97a27770af1" name="jetbrains.mps.logic">
-      <concept id="238586457668550951" name="jetbrains.mps.logic.structure.NodeSubstitution" flags="ng" index="22Ky0T">
+      <concept id="238586457668550951" name="jetbrains.mps.logic.structure.LogicalSubstitution" flags="ng" index="22Ky0T">
         <child id="238586457668550958" name="expression" index="22Ky0K" />
       </concept>
       <concept id="6726466946035358271" name="jetbrains.mps.logic.structure.ValueExpression" flags="ng" index="3iwiKN">
@@ -1301,8 +1301,8 @@
                         <ref role="37wK5l" to="jfki:~Substitution.Binding.var()" resolve="var" />
                       </node>
                     </node>
-                    <node concept="liA8E" id="3JgCwkqBAVm" role="2OqNvi">
-                      <ref role="37wK5l" to="jfki:~Var.name()" resolve="name" />
+                    <node concept="liA8E" id="56MMu0Awe2w" role="2OqNvi">
+                      <ref role="37wK5l" to="jfki:~Node.symbol()" resolve="symbol" />
                     </node>
                   </node>
                 </node>
diff --git a/solutions/jetbrains.mps.typechecking.handling/models/jetbrains/mps/typechecking/handler/producer.mps b/solutions/jetbrains.mps.typechecking.handling/models/jetbrains/mps/typechecking/handler/producer.mps
index ecddf878..d3ebab6c 100644
--- a/solutions/jetbrains.mps.typechecking.handling/models/jetbrains/mps/typechecking/handler/producer.mps
+++ b/solutions/jetbrains.mps.typechecking.handling/models/jetbrains/mps/typechecking/handler/producer.mps
@@ -3551,19 +3551,6 @@
             </node>
             <node concept="3clFbF" id="4sVJFklNhai" role="3cqZAp">
               <node concept="37vLTI" id="4sVJFklNln7" role="3clFbG">
-                <node concept="2OqwBi" id="4sVJFklNmbq" role="37vLTx">
-                  <node concept="2OqwBi" id="4sVJFklNlxY" role="2Oq$k0">
-                    <node concept="37vLTw" id="4sVJFklNlw$" role="2Oq$k0">
-                      <ref role="3cqZAo" node="5s497VqXKRl" resolve="tbr" />
-                    </node>
-                    <node concept="liA8E" id="4sVJFklNlOX" role="2OqNvi">
-                      <ref role="37wK5l" to="jfki:~Node.asVar()" resolve="asVar" />
-                    </node>
-                  </node>
-                  <node concept="liA8E" id="4sVJFklNnA4" role="2OqNvi">
-                    <ref role="37wK5l" to="jfki:~Var.name()" resolve="name" />
-                  </node>
-                </node>
                 <node concept="2OqwBi" id="4sVJFklNkGk" role="37vLTJ">
                   <node concept="37vLTw" id="4sVJFklNkAO" role="2Oq$k0">
                     <ref role="3cqZAo" node="4sVJFklNkAI" resolve="varNode" />
@@ -3572,6 +3559,18 @@
                     <ref role="3TsBF5" to="tpck:h0TrG11" resolve="name" />
                   </node>
                 </node>
+                <node concept="2YIFZM" id="56MMu0Aqu2g" role="37vLTx">
+                  <ref role="37wK5l" to="e2lb:~String.valueOf(java.lang.Object):java.lang.String" resolve="valueOf" />
+                  <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
+                  <node concept="2OqwBi" id="4sVJFklNmbq" role="37wK5m">
+                    <node concept="37vLTw" id="4sVJFklNlw$" role="2Oq$k0">
+                      <ref role="3cqZAo" node="5s497VqXKRl" resolve="tbr" />
+                    </node>
+                    <node concept="liA8E" id="4sVJFklNnA4" role="2OqNvi">
+                      <ref role="37wK5l" to="jfki:~Node.symbol()" resolve="symbol" />
+                    </node>
+                  </node>
+                </node>
               </node>
             </node>
           </node>
@@ -3579,8 +3578,12 @@
             <node concept="37vLTw" id="4sVJFklMn7y" role="2Oq$k0">
               <ref role="3cqZAo" node="5s497VqXKRl" resolve="tbr" />
             </node>
-            <node concept="liA8E" id="4sVJFklMnxX" role="2OqNvi">
-              <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+            <node concept="liA8E" id="56MMu0ApUmr" role="2OqNvi">
+              <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+              <node concept="Rm8GO" id="56MMu0ApUms" role="37wK5m">
+                <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+              </node>
             </node>
           </node>
           <node concept="9aQIb" id="4sVJFklMnzF" role="9aQIa">
@@ -4749,20 +4752,24 @@
                   <node concept="3clFbH" id="2q_78a90oRv" role="3cqZAp" />
                 </node>
                 <node concept="2OqwBi" id="677NV56dk3K" role="3clFbw">
-                  <node concept="2OqwBi" id="677NV56dho9" role="2Oq$k0">
-                    <node concept="37vLTw" id="677NV56dguQ" role="2Oq$k0">
-                      <ref role="3cqZAo" node="104EUzG3OTw" resolve="variable" />
-                    </node>
-                    <node concept="liA8E" id="677NV56djRJ" role="2OqNvi">
-                      <ref role="37wK5l" to="ie8e:uNmovXiEdQ" resolve="name" />
-                    </node>
-                  </node>
                   <node concept="liA8E" id="677NV56dlaq" role="2OqNvi">
                     <ref role="37wK5l" to="e2lb:~String.startsWith(java.lang.String):boolean" resolve="startsWith" />
                     <node concept="Xl_RD" id="677NV56dlcE" role="37wK5m">
                       <property role="Xl_RC" value="$" />
                     </node>
                   </node>
+                  <node concept="2YIFZM" id="31Jz$8bZWnC" role="2Oq$k0">
+                    <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
+                    <ref role="37wK5l" to="e2lb:~String.valueOf(java.lang.Object):java.lang.String" resolve="valueOf" />
+                    <node concept="2OqwBi" id="31Jz$8bZWnD" role="37wK5m">
+                      <node concept="37vLTw" id="31Jz$8bZWnE" role="2Oq$k0">
+                        <ref role="3cqZAo" node="104EUzG3OTw" resolve="variable" />
+                      </node>
+                      <node concept="liA8E" id="31Jz$8bZWnF" role="2OqNvi">
+                        <ref role="37wK5l" to="ie8e:56MMu0Ark7d" resolve="symbol" />
+                      </node>
+                    </node>
+                  </node>
                 </node>
                 <node concept="9aQIb" id="2q_78a90oeF" role="9aQIa">
                   <node concept="3clFbS" id="2q_78a90oeG" role="9aQI4">
@@ -4842,12 +4849,16 @@
                             <ref role="3TsBF5" to="tpck:h0TrG11" resolve="name" />
                           </node>
                         </node>
-                        <node concept="2OqwBi" id="2q_78a8qgnc" role="37vLTx">
-                          <node concept="37vLTw" id="2q_78a8qgnd" role="2Oq$k0">
-                            <ref role="3cqZAo" node="104EUzG3OTw" resolve="variable" />
-                          </node>
-                          <node concept="liA8E" id="2q_78a8qgne" role="2OqNvi">
-                            <ref role="37wK5l" to="ie8e:uNmovXiEdQ" resolve="name" />
+                        <node concept="2YIFZM" id="31Jz$8bZPXE" role="37vLTx">
+                          <ref role="37wK5l" to="e2lb:~String.valueOf(java.lang.Object):java.lang.String" resolve="valueOf" />
+                          <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
+                          <node concept="2OqwBi" id="31Jz$8bZRWl" role="37wK5m">
+                            <node concept="37vLTw" id="31Jz$8bZQ4I" role="2Oq$k0">
+                              <ref role="3cqZAo" node="104EUzG3OTw" resolve="variable" />
+                            </node>
+                            <node concept="liA8E" id="31Jz$8bZT96" role="2OqNvi">
+                              <ref role="37wK5l" to="ie8e:56MMu0Ark7d" resolve="symbol" />
+                            </node>
                           </node>
                         </node>
                       </node>
diff --git a/solutions/jetbrains.mps.typechecking.solving/models/jetbrains/mps/typechecking/builtin/containment.mps b/solutions/jetbrains.mps.typechecking.solving/models/jetbrains/mps/typechecking/builtin/containment.mps
index b954b3bc..bab231d3 100644
--- a/solutions/jetbrains.mps.typechecking.solving/models/jetbrains/mps/typechecking/builtin/containment.mps
+++ b/solutions/jetbrains.mps.typechecking.solving/models/jetbrains/mps/typechecking/builtin/containment.mps
@@ -13,8 +13,8 @@
     <import index="c87j" ref="r:db5d11a3-3c62-4a1b-ace3-b983df6a66b4(jetbrains.mps.type.inference.common)" />
     <import index="mqgp" ref="r:df98e090-e1cf-4263-9336-dc1ffd952995(jetbrains.mps.typechecking.builtin.conversion)" />
     <import index="7uia" ref="f:java_stub#a5478664-6b44-4c62-a9f7-434f8aa57eee#runtime(runtime@java_stub)" />
+    <import index="jfki" ref="7526e0cf-1ce7-46f8-a555-9eca1e06c23b/f:java_stub#7526e0cf-1ce7-46f8-a555-9eca1e06c23b#jetbrains.mps.unification(jetbrains.mps.unification.tree/jetbrains.mps.unification@java_stub)" />
     <import index="e2lb" ref="f:java_stub#6354ebe7-c22a-4a0f-ac54-50b52ab9b065#java.lang(JDK/java.lang@java_stub)" implicit="true" />
-    <import index="jfki" ref="f:java_stub#7526e0cf-1ce7-46f8-a555-9eca1e06c23b#jetbrains.mps.unification(jetbrains.mps.unification@java_stub)" implicit="true" />
   </imports>
   <registry>
     <language id="f3061a53-9226-4cc5-a443-f952ceaf5816" name="jetbrains.mps.baseLanguage">
@@ -679,8 +679,12 @@
                   <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                 </node>
               </node>
-              <node concept="liA8E" id="7d$oK1$Bdj8" role="2OqNvi">
-                <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+              <node concept="liA8E" id="56MMu0Ap1Z2" role="2OqNvi">
+                <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                <node concept="Rm8GO" id="56MMu0Ap21O" role="37wK5m">
+                  <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                  <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                </node>
               </node>
             </node>
             <node concept="2OqwBi" id="7d$oK1$Bbf8" role="3uHU7B">
@@ -692,8 +696,12 @@
                   <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                 </node>
               </node>
-              <node concept="liA8E" id="7d$oK1$Bc6k" role="2OqNvi">
-                <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+              <node concept="liA8E" id="56MMu0Ap8dj" role="2OqNvi">
+                <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                <node concept="Rm8GO" id="56MMu0Ap8dk" role="37wK5m">
+                  <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                  <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                </node>
               </node>
             </node>
           </node>
@@ -749,8 +757,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="7d$oK1$BiiZ" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0AqiSo" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0AqiSp" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
               <node concept="2OqwBi" id="7d$oK1$BiEd" role="3uHU7w">
@@ -762,8 +774,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="7d$oK1$BiEh" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+                <node concept="liA8E" id="56MMu0Ap7To" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0Ap7Tp" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                  </node>
                 </node>
               </node>
             </node>
@@ -820,8 +836,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="7d$oK1$BrLy" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0Aqjyf" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0Aqjyg" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
               <node concept="2OqwBi" id="7d$oK1$BrLz" role="3uHU7B">
@@ -833,8 +853,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="7d$oK1$BrLB" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+                <node concept="liA8E" id="56MMu0Ap7zP" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0Ap7zQ" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                  </node>
                 </node>
               </node>
             </node>
@@ -907,8 +931,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="7d$oK1$B_9D" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0Aqjea" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0Aqjeb" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
               <node concept="2OqwBi" id="7d$oK1$B_9E" role="3uHU7B">
@@ -920,8 +948,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="7d$oK1$B_9I" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0AqjqQ" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0AqjqR" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
             </node>
@@ -1048,8 +1080,12 @@
                   <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                 </node>
               </node>
-              <node concept="liA8E" id="7d$oK1$BQco" role="2OqNvi">
-                <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+              <node concept="liA8E" id="56MMu0Ap83i" role="2OqNvi">
+                <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                <node concept="Rm8GO" id="56MMu0Ap83j" role="37wK5m">
+                  <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                  <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                </node>
               </node>
             </node>
             <node concept="2OqwBi" id="7d$oK1$BQcp" role="3uHU7B">
@@ -1061,8 +1097,12 @@
                   <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                 </node>
               </node>
-              <node concept="liA8E" id="7d$oK1$BQct" role="2OqNvi">
-                <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+              <node concept="liA8E" id="56MMu0Ap7Jy" role="2OqNvi">
+                <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                <node concept="Rm8GO" id="56MMu0Ap7Jz" role="37wK5m">
+                  <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                  <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                </node>
               </node>
             </node>
           </node>
@@ -1119,8 +1159,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="7d$oK1$BQcO" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0Aqj6W" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0Aqj6X" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
               <node concept="2OqwBi" id="7d$oK1$BQcP" role="3uHU7w">
@@ -1132,8 +1176,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="7d$oK1$BQcT" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+                <node concept="liA8E" id="56MMu0Ap8ng" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0Ap8nh" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                  </node>
                 </node>
               </node>
             </node>
@@ -1191,8 +1239,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="7d$oK1$BQdg" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0AqiZI" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0AqiZJ" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
               <node concept="2OqwBi" id="7d$oK1$BQdh" role="3uHU7B">
@@ -1204,8 +1256,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="7d$oK1$BQdl" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+                <node concept="liA8E" id="56MMu0Ap7qM" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0Ap7qN" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                  </node>
                 </node>
               </node>
             </node>
@@ -1279,8 +1335,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="7d$oK1$BQdN" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0AqjjC" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0AqjjD" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
               <node concept="2OqwBi" id="7d$oK1$BQdO" role="3uHU7B">
@@ -1292,8 +1352,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="7d$oK1$BQdS" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0ApUmr" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0ApUms" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
             </node>
diff --git a/solutions/jetbrains.mps.typechecking.solving/models/jetbrains/mps/typechecking/builtin/conversion.mps b/solutions/jetbrains.mps.typechecking.solving/models/jetbrains/mps/typechecking/builtin/conversion.mps
index 270306c9..c7c4feec 100644
--- a/solutions/jetbrains.mps.typechecking.solving/models/jetbrains/mps/typechecking/builtin/conversion.mps
+++ b/solutions/jetbrains.mps.typechecking.solving/models/jetbrains/mps/typechecking/builtin/conversion.mps
@@ -2316,8 +2316,12 @@
                   <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                 </node>
               </node>
-              <node concept="liA8E" id="7d$oK1$Bdj8" role="2OqNvi">
-                <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+              <node concept="liA8E" id="56MMu0Ap1Z2" role="2OqNvi">
+                <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                <node concept="Rm8GO" id="56MMu0Ap21O" role="37wK5m">
+                  <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                  <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                </node>
               </node>
             </node>
             <node concept="2OqwBi" id="7d$oK1$Bbf8" role="3uHU7B">
@@ -2329,8 +2333,12 @@
                   <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                 </node>
               </node>
-              <node concept="liA8E" id="7d$oK1$Bc6k" role="2OqNvi">
-                <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+              <node concept="liA8E" id="56MMu0AparB" role="2OqNvi">
+                <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                <node concept="Rm8GO" id="56MMu0AparC" role="37wK5m">
+                  <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                  <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                </node>
               </node>
             </node>
           </node>
@@ -2386,8 +2394,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="5PpdwMfE$t0" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+                <node concept="liA8E" id="56MMu0Apa_D" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0Apa_E" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                  </node>
                 </node>
               </node>
               <node concept="2OqwBi" id="5PpdwMfE$t1" role="3uHU7B">
@@ -2399,8 +2411,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="5PpdwMfE$t5" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0AqkUw" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0AqkUx" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
             </node>
@@ -2457,8 +2473,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="5PpdwMfE_4B" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0Aqkv6" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0Aqkv7" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
               <node concept="2OqwBi" id="5PpdwMfE_4C" role="3uHU7B">
@@ -2470,8 +2490,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="5PpdwMfE_4G" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+                <node concept="liA8E" id="56MMu0ApaTo" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0ApaTp" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                  </node>
                 </node>
               </node>
             </node>
@@ -2544,8 +2568,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="5PpdwMfEAqr" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0AqkHD" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0AqkHE" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
               <node concept="2OqwBi" id="5PpdwMfEAqs" role="3uHU7B">
@@ -2557,8 +2585,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="5PpdwMfEAqw" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0AqkN7" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0AqkN8" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
             </node>
@@ -2659,8 +2691,12 @@
                   <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                 </node>
               </node>
-              <node concept="liA8E" id="5PpdwMfF9Qy" role="2OqNvi">
-                <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+              <node concept="liA8E" id="56MMu0ApaJy" role="2OqNvi">
+                <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                <node concept="Rm8GO" id="56MMu0ApaJz" role="37wK5m">
+                  <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                  <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                </node>
               </node>
             </node>
             <node concept="2OqwBi" id="5PpdwMfF9Qz" role="3uHU7B">
@@ -2672,8 +2708,12 @@
                   <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                 </node>
               </node>
-              <node concept="liA8E" id="5PpdwMfF9QB" role="2OqNvi">
-                <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+              <node concept="liA8E" id="56MMu0ApbeZ" role="2OqNvi">
+                <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                <node concept="Rm8GO" id="56MMu0Apbf0" role="37wK5m">
+                  <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                  <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                </node>
               </node>
             </node>
           </node>
@@ -2730,8 +2770,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="5PpdwMfF9QZ" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+                <node concept="liA8E" id="56MMu0ApboL" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0ApboM" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                  </node>
                 </node>
               </node>
               <node concept="2OqwBi" id="5PpdwMfF9R0" role="3uHU7B">
@@ -2743,8 +2787,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="5PpdwMfF9R4" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0ApUmr" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0ApUms" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
             </node>
@@ -2802,8 +2850,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="5PpdwMfF9Rs" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0Aql7j" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0Aql7k" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
               <node concept="2OqwBi" id="5PpdwMfF9Rt" role="3uHU7B">
@@ -2815,8 +2867,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="5PpdwMfF9Rx" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isTerm()" resolve="isTerm" />
+                <node concept="liA8E" id="56MMu0Apb3h" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0Apb3i" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+                  </node>
                 </node>
               </node>
             </node>
@@ -2890,8 +2946,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="5PpdwMfF9RZ" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0Aql1T" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0Aql1U" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
               <node concept="2OqwBi" id="5PpdwMfF9S0" role="3uHU7B">
@@ -2903,8 +2963,12 @@
                     <ref role="37wK5l" to="ie8e:2xQ7eRACJS8" resolve="root" />
                   </node>
                 </node>
-                <node concept="liA8E" id="5PpdwMfF9S4" role="2OqNvi">
-                  <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+                <node concept="liA8E" id="56MMu0AqkAv" role="2OqNvi">
+                  <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+                  <node concept="Rm8GO" id="56MMu0AqkAw" role="37wK5m">
+                    <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                    <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+                  </node>
                 </node>
               </node>
             </node>
diff --git a/solutions/jetbrains.mps.unification.tree/models/jetbrains/mps/unification/tree.mps b/solutions/jetbrains.mps.unification.tree/models/jetbrains/mps/unification/tree.mps
index 32ee8253..a1b14144 100644
--- a/solutions/jetbrains.mps.unification.tree/models/jetbrains/mps/unification/tree.mps
+++ b/solutions/jetbrains.mps.unification.tree/models/jetbrains/mps/unification/tree.mps
@@ -160,7 +160,7 @@
         <child id="1068580123161" name="ifTrue" index="3clFbx" />
         <child id="1206060520071" name="elsifClauses" index="3eNLev" />
       </concept>
-      <concept id="1068580123136" name="jetbrains.mps.baseLanguage.structure.StatementList" flags="sn" stub="5293379017992965193" index="3clFbS">
+      <concept id="1068580123136" name="jetbrains.mps.baseLanguage.structure.StatementList" flags="sn" index="3clFbS">
         <child id="1068581517665" name="statement" index="3cqZAp" />
       </concept>
       <concept id="1068580123137" name="jetbrains.mps.baseLanguage.structure.BooleanConstant" flags="nn" index="3clFbT">
@@ -750,84 +750,100 @@
       </node>
     </node>
     <node concept="2tJIrI" id="104EUzFNTqX" role="jymVt" />
-    <node concept="3clFb_" id="104EUzFNSR8" role="jymVt">
+    <node concept="3clFb_" id="56MMu0AqCg1" role="jymVt">
       <property role="1EzhhJ" value="false" />
-      <property role="TrG5h" value="isTerm" />
+      <property role="TrG5h" value="is" />
       <property role="DiZV1" value="false" />
       <property role="od$2w" value="false" />
-      <node concept="3Tm1VV" id="104EUzFNSR9" role="1B3o_S" />
-      <node concept="10P_77" id="104EUzFNSRa" role="3clF45" />
-      <node concept="3clFbS" id="104EUzFNSRb" role="3clF47">
-        <node concept="3clFbF" id="104EUzFNSRc" role="3cqZAp">
-          <node concept="3clFbT" id="104EUzFNSRd" role="3clFbG">
-            <property role="3clFbU" value="true" />
-          </node>
+      <node concept="3Tm1VV" id="56MMu0AqCg2" role="1B3o_S" />
+      <node concept="37vLTG" id="56MMu0AqCg3" role="3clF46">
+        <property role="TrG5h" value="kind" />
+        <property role="3TUv4t" value="false" />
+        <node concept="3uibUv" id="56MMu0AqCg4" role="1tU5fm">
+          <ref role="3uigEE" to="jfki:~Node.Kind" resolve="Node.Kind" />
         </node>
       </node>
-      <node concept="2AHcQZ" id="104EUzFNSRe" role="2AJF6D">
-        <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
-      </node>
-    </node>
-    <node concept="2tJIrI" id="104EUzFNSRf" role="jymVt" />
-    <node concept="3clFb_" id="104EUzFNSRg" role="jymVt">
-      <property role="1EzhhJ" value="false" />
-      <property role="TrG5h" value="asTerm" />
-      <property role="DiZV1" value="false" />
-      <property role="od$2w" value="false" />
-      <node concept="3Tm1VV" id="104EUzFNSRh" role="1B3o_S" />
-      <node concept="3uibUv" id="104EUzFNSRi" role="3clF45">
-        <ref role="3uigEE" to="jfki:~Term" resolve="Term" />
-      </node>
-      <node concept="3clFbS" id="104EUzFNSRj" role="3clF47">
-        <node concept="3clFbF" id="104EUzFNSRk" role="3cqZAp">
-          <node concept="Xjq3P" id="104EUzFNSRl" role="3clFbG" />
-        </node>
-      </node>
-      <node concept="2AHcQZ" id="104EUzFNSRm" role="2AJF6D">
-        <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
-      </node>
-    </node>
-    <node concept="2tJIrI" id="104EUzFNSRn" role="jymVt" />
-    <node concept="3clFb_" id="104EUzFNSRo" role="jymVt">
-      <property role="1EzhhJ" value="false" />
-      <property role="TrG5h" value="isVar" />
-      <property role="DiZV1" value="false" />
-      <property role="od$2w" value="false" />
-      <node concept="3Tm1VV" id="104EUzFNSRp" role="1B3o_S" />
-      <node concept="10P_77" id="104EUzFNSRq" role="3clF45" />
-      <node concept="3clFbS" id="104EUzFNSRr" role="3clF47">
-        <node concept="3clFbF" id="104EUzFNSRs" role="3cqZAp">
-          <node concept="3clFbT" id="104EUzFNSRt" role="3clFbG" />
-        </node>
-      </node>
-      <node concept="2AHcQZ" id="104EUzFNSRu" role="2AJF6D">
-        <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
-      </node>
-    </node>
-    <node concept="2tJIrI" id="104EUzFNSRv" role="jymVt" />
-    <node concept="3clFb_" id="104EUzFNSRw" role="jymVt">
-      <property role="1EzhhJ" value="false" />
-      <property role="TrG5h" value="asVar" />
-      <property role="DiZV1" value="false" />
-      <property role="od$2w" value="false" />
-      <node concept="3Tm1VV" id="104EUzFNSRx" role="1B3o_S" />
-      <node concept="3uibUv" id="104EUzFNSRy" role="3clF45">
-        <ref role="3uigEE" to="jfki:~Var" resolve="Var" />
-      </node>
-      <node concept="3clFbS" id="104EUzFNSRz" role="3clF47">
-        <node concept="YS8fn" id="104EUzFNSR$" role="3cqZAp">
-          <node concept="2ShNRf" id="104EUzFNSR_" role="YScLw">
-            <node concept="1pGfFk" id="104EUzFNSRA" role="2ShVmc">
-              <ref role="37wK5l" to="e2lb:~IllegalStateException.&lt;init&gt;()" resolve="IllegalStateException" />
+      <node concept="10P_77" id="56MMu0AqCg6" role="3clF45" />
+      <node concept="3clFbS" id="56MMu0AqCg8" role="3clF47">
+        <node concept="3clFbF" id="56MMu0AqDhG" role="3cqZAp">
+          <node concept="3clFbC" id="56MMu0AqDoI" role="3clFbG">
+            <node concept="37vLTw" id="56MMu0AqD_r" role="3uHU7w">
+              <ref role="3cqZAo" node="56MMu0AqCg3" resolve="kind" />
+            </node>
+            <node concept="Rm8GO" id="56MMu0Ar5d$" role="3uHU7B">
+              <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+              <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
             </node>
           </node>
         </node>
       </node>
-      <node concept="2AHcQZ" id="104EUzFNSRB" role="2AJF6D">
+    </node>
+    <node concept="2tJIrI" id="56MMu0AqCLx" role="jymVt" />
+    <node concept="3clFb_" id="56MMu0Ar0iE" role="jymVt">
+      <property role="1EzhhJ" value="false" />
+      <property role="TrG5h" value="get" />
+      <property role="DiZV1" value="false" />
+      <property role="od$2w" value="false" />
+      <node concept="3Tm1VV" id="56MMu0Ar0iF" role="1B3o_S" />
+      <node concept="3uibUv" id="56MMu0Ar0iH" role="3clF45">
+        <ref role="3uigEE" to="jfki:~Node" resolve="Node" />
+      </node>
+      <node concept="3clFbS" id="56MMu0Ar0iJ" role="3clF47">
+        <node concept="3clFbF" id="56MMu0Ar3LN" role="3cqZAp">
+          <node concept="Xjq3P" id="56MMu0Ar3LM" role="3clFbG" />
+        </node>
+      </node>
+      <node concept="2AHcQZ" id="56MMu0Ar3kp" role="2AJF6D">
         <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
       </node>
     </node>
-    <node concept="2tJIrI" id="5PpdwMfO3jx" role="jymVt" />
+    <node concept="2tJIrI" id="56MMu0Ar1oi" role="jymVt" />
+    <node concept="3clFb_" id="56MMu0Ar0iM" role="jymVt">
+      <property role="1EzhhJ" value="false" />
+      <property role="TrG5h" value="compareTo" />
+      <property role="DiZV1" value="false" />
+      <property role="IEkAT" value="false" />
+      <node concept="3Tm1VV" id="56MMu0Ar0iN" role="1B3o_S" />
+      <node concept="10Oyi0" id="56MMu0Ar0iP" role="3clF45" />
+      <node concept="37vLTG" id="56MMu0Ar0iQ" role="3clF46">
+        <property role="TrG5h" value="node" />
+        <node concept="3uibUv" id="56MMu0Ar0iV" role="1tU5fm">
+          <ref role="3uigEE" to="jfki:~Node" resolve="Node" />
+        </node>
+      </node>
+      <node concept="3clFbS" id="56MMu0Ar0iW" role="3clF47">
+        <node concept="3clFbF" id="56MMu0Ar9PX" role="3cqZAp">
+          <node concept="2OqwBi" id="56MMu0Ar9PY" role="3clFbG">
+            <node concept="2YIFZM" id="56MMu0Ar9PZ" role="2Oq$k0">
+              <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
+              <ref role="37wK5l" to="e2lb:~String.valueOf(java.lang.Object):java.lang.String" resolve="valueOf" />
+              <node concept="1rXfSq" id="56MMu0Ar9Q0" role="37wK5m">
+                <ref role="37wK5l" node="1msb0mq8QTt" resolve="symbol" />
+              </node>
+            </node>
+            <node concept="liA8E" id="56MMu0Ar9Q1" role="2OqNvi">
+              <ref role="37wK5l" to="e2lb:~String.compareTo(java.lang.String):int" resolve="compareTo" />
+              <node concept="2YIFZM" id="56MMu0Ar9Q2" role="37wK5m">
+                <ref role="37wK5l" to="e2lb:~String.valueOf(java.lang.Object):java.lang.String" resolve="valueOf" />
+                <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
+                <node concept="2OqwBi" id="56MMu0Ar9Q3" role="37wK5m">
+                  <node concept="37vLTw" id="56MMu0Ar9Q4" role="2Oq$k0">
+                    <ref role="3cqZAo" node="56MMu0Ar0iQ" resolve="node" />
+                  </node>
+                  <node concept="liA8E" id="56MMu0Ar9Q5" role="2OqNvi">
+                    <ref role="37wK5l" to="jfki:~Node.symbol()" resolve="symbol" />
+                  </node>
+                </node>
+              </node>
+            </node>
+          </node>
+        </node>
+      </node>
+      <node concept="2AHcQZ" id="56MMu0Ar6QW" role="2AJF6D">
+        <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
+      </node>
+    </node>
+    <node concept="2tJIrI" id="56MMu0Ar0Rq" role="jymVt" />
     <node concept="3clFb_" id="1bm7a6EZTKC" role="jymVt">
       <property role="1EzhhJ" value="false" />
       <property role="TrG5h" value="copyRecursively" />
@@ -859,8 +875,8 @@
       </node>
       <node concept="3uibUv" id="3OPtF02UIn0" role="3clF45">
         <ref role="3uigEE" node="1bm7a6EXvsP" resolve="ITreePart" />
-        <node concept="3uibUv" id="3OPtF02UIn8" role="11_B2D">
-          <ref role="3uigEE" to="jfki:~Term" resolve="Term" />
+        <node concept="3uibUv" id="56MMu0AqFbI" role="11_B2D">
+          <ref role="3uigEE" to="jfki:~Node" resolve="Node" />
         </node>
       </node>
       <node concept="3Tm1VV" id="3OPtF02UIn2" role="1B3o_S" />
@@ -977,13 +993,10 @@
     <node concept="16euLQ" id="1msb0mq99pI" role="16eVyc">
       <property role="TrG5h" value="V" />
     </node>
-    <node concept="3uibUv" id="104EUzFNYxa" role="EKbjA">
-      <ref role="3uigEE" to="jfki:~Term" resolve="Term" />
-    </node>
     <node concept="3uibUv" id="104EUzFNZ6w" role="EKbjA">
       <ref role="3uigEE" node="1bm7a6EXvsP" resolve="ITreePart" />
-      <node concept="3uibUv" id="104EUzFNZS8" role="11_B2D">
-        <ref role="3uigEE" to="jfki:~Term" resolve="Term" />
+      <node concept="3uibUv" id="56MMu0AqyMv" role="11_B2D">
+        <ref role="3uigEE" to="jfki:~Node" resolve="Node" />
       </node>
     </node>
     <node concept="3clFb_" id="1mP5b6jQ__L" role="jymVt">
@@ -1599,9 +1612,6 @@
     <property role="TrG5h" value="Branch" />
     <property role="1sVAO0" value="true" />
     <node concept="3Tm1VV" id="1msb0mq9ID5" role="1B3o_S" />
-    <node concept="3uibUv" id="1msb0mq9ID_" role="EKbjA">
-      <ref role="3uigEE" to="jfki:~Term" resolve="Term" />
-    </node>
     <node concept="3uibUv" id="104EUzGgROM" role="EKbjA">
       <ref role="3uigEE" node="1bm7a6EXvsP" resolve="ITreePart" />
       <node concept="3uibUv" id="104EUzGgTtD" role="11_B2D">
@@ -1691,84 +1701,38 @@
       </node>
     </node>
     <node concept="2tJIrI" id="5JQSuNswjSq" role="jymVt" />
-    <node concept="3clFb_" id="5JQSuNswjSr" role="jymVt">
+    <node concept="3clFb_" id="1pPMb_vk4Mo" role="jymVt">
       <property role="1EzhhJ" value="false" />
-      <property role="TrG5h" value="isTerm" />
+      <property role="TrG5h" value="is" />
       <property role="DiZV1" value="false" />
       <property role="od$2w" value="false" />
-      <node concept="3Tm1VV" id="5JQSuNswjSs" role="1B3o_S" />
-      <node concept="10P_77" id="5JQSuNswjSt" role="3clF45" />
-      <node concept="3clFbS" id="5JQSuNswjSu" role="3clF47">
-        <node concept="3clFbF" id="5JQSuNswjSv" role="3cqZAp">
-          <node concept="3clFbT" id="5JQSuNswjSw" role="3clFbG">
-            <property role="3clFbU" value="true" />
-          </node>
+      <node concept="3Tm1VV" id="1pPMb_vk4Mp" role="1B3o_S" />
+      <node concept="37vLTG" id="1pPMb_vk4Mq" role="3clF46">
+        <property role="TrG5h" value="kind" />
+        <property role="3TUv4t" value="false" />
+        <node concept="3uibUv" id="1pPMb_vk4Mr" role="1tU5fm">
+          <ref role="3uigEE" to="jfki:~Node.Kind" resolve="Node.Kind" />
         </node>
       </node>
-      <node concept="2AHcQZ" id="5JQSuNswjSx" role="2AJF6D">
-        <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
-      </node>
-    </node>
-    <node concept="2tJIrI" id="5JQSuNswKNs" role="jymVt" />
-    <node concept="3clFb_" id="5JQSuNswjSy" role="jymVt">
-      <property role="1EzhhJ" value="false" />
-      <property role="TrG5h" value="asTerm" />
-      <property role="DiZV1" value="false" />
-      <property role="od$2w" value="false" />
-      <node concept="3Tm1VV" id="5JQSuNswjSz" role="1B3o_S" />
-      <node concept="3uibUv" id="5JQSuNswjS$" role="3clF45">
-        <ref role="3uigEE" to="jfki:~Term" resolve="Term" />
-      </node>
-      <node concept="3clFbS" id="5JQSuNswjS_" role="3clF47">
-        <node concept="3clFbF" id="5JQSuNswjSA" role="3cqZAp">
-          <node concept="Xjq3P" id="5JQSuNswjSB" role="3clFbG" />
-        </node>
-      </node>
-      <node concept="2AHcQZ" id="5JQSuNswjSC" role="2AJF6D">
-        <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
-      </node>
-    </node>
-    <node concept="2tJIrI" id="5JQSuNswL7e" role="jymVt" />
-    <node concept="3clFb_" id="5JQSuNswjSD" role="jymVt">
-      <property role="1EzhhJ" value="false" />
-      <property role="TrG5h" value="isVar" />
-      <property role="DiZV1" value="false" />
-      <property role="od$2w" value="false" />
-      <node concept="3Tm1VV" id="5JQSuNswjSE" role="1B3o_S" />
-      <node concept="10P_77" id="5JQSuNswjSF" role="3clF45" />
-      <node concept="3clFbS" id="5JQSuNswjSG" role="3clF47">
-        <node concept="3clFbF" id="5JQSuNswjSH" role="3cqZAp">
-          <node concept="3clFbT" id="5JQSuNswjSI" role="3clFbG" />
-        </node>
-      </node>
-      <node concept="2AHcQZ" id="5JQSuNswjSJ" role="2AJF6D">
-        <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
-      </node>
-    </node>
-    <node concept="2tJIrI" id="5JQSuNswLpf" role="jymVt" />
-    <node concept="3clFb_" id="5JQSuNswjSK" role="jymVt">
-      <property role="1EzhhJ" value="false" />
-      <property role="TrG5h" value="asVar" />
-      <property role="DiZV1" value="false" />
-      <property role="od$2w" value="false" />
-      <node concept="3Tm1VV" id="5JQSuNswjSL" role="1B3o_S" />
-      <node concept="3uibUv" id="5JQSuNswjSM" role="3clF45">
-        <ref role="3uigEE" to="jfki:~Var" resolve="Var" />
-      </node>
-      <node concept="3clFbS" id="5JQSuNswjSN" role="3clF47">
-        <node concept="YS8fn" id="5JQSuNswjSO" role="3cqZAp">
-          <node concept="2ShNRf" id="5JQSuNswjSP" role="YScLw">
-            <node concept="1pGfFk" id="5JQSuNswjSQ" role="2ShVmc">
-              <ref role="37wK5l" to="e2lb:~IllegalStateException.&lt;init&gt;()" resolve="IllegalStateException" />
+      <node concept="10P_77" id="1pPMb_vk4Mt" role="3clF45" />
+      <node concept="3clFbS" id="1pPMb_vk4Mv" role="3clF47">
+        <node concept="3clFbF" id="56MMu0AoGpA" role="3cqZAp">
+          <node concept="3clFbC" id="56MMu0AoGG2" role="3clFbG">
+            <node concept="37vLTw" id="56MMu0AoGH8" role="3uHU7w">
+              <ref role="3cqZAo" node="1pPMb_vk4Mq" resolve="kind" />
+            </node>
+            <node concept="Rm8GO" id="56MMu0AoG_N" role="3uHU7B">
+              <ref role="Rm8GQ" to="jfki:~Node.FUN" resolve="FUN" />
+              <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
             </node>
           </node>
         </node>
       </node>
-      <node concept="2AHcQZ" id="5JQSuNswjSR" role="2AJF6D">
+      <node concept="2AHcQZ" id="56MMu0AqLmA" role="2AJF6D">
         <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
       </node>
     </node>
-    <node concept="2tJIrI" id="5JQSuNs$iz_" role="jymVt" />
+    <node concept="2tJIrI" id="1pPMb_vk6RW" role="jymVt" />
     <node concept="3clFb_" id="1R$Cm9qGRoH" role="jymVt">
       <property role="1EzhhJ" value="false" />
       <property role="TrG5h" value="symbol" />
@@ -1790,8 +1754,76 @@
           </node>
         </node>
       </node>
+      <node concept="2AHcQZ" id="56MMu0AqKC6" role="2AJF6D">
+        <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
+      </node>
     </node>
     <node concept="2tJIrI" id="1R$Cm9qGWIx" role="jymVt" />
+    <node concept="3clFb_" id="56MMu0AqMKf" role="jymVt">
+      <property role="1EzhhJ" value="false" />
+      <property role="TrG5h" value="get" />
+      <property role="DiZV1" value="false" />
+      <property role="od$2w" value="false" />
+      <node concept="3Tm1VV" id="56MMu0AqMKg" role="1B3o_S" />
+      <node concept="3uibUv" id="56MMu0AqMKi" role="3clF45">
+        <ref role="3uigEE" to="jfki:~Node" resolve="Node" />
+      </node>
+      <node concept="3clFbS" id="56MMu0AqMKk" role="3clF47">
+        <node concept="3clFbF" id="56MMu0AqPP2" role="3cqZAp">
+          <node concept="Xjq3P" id="56MMu0AqPP1" role="3clFbG" />
+        </node>
+      </node>
+      <node concept="2AHcQZ" id="56MMu0AqNCl" role="2AJF6D">
+        <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
+      </node>
+    </node>
+    <node concept="2tJIrI" id="56MMu0AqP1W" role="jymVt" />
+    <node concept="3clFb_" id="56MMu0AqMKn" role="jymVt">
+      <property role="1EzhhJ" value="false" />
+      <property role="TrG5h" value="compareTo" />
+      <property role="DiZV1" value="false" />
+      <property role="IEkAT" value="false" />
+      <node concept="3Tm1VV" id="56MMu0AqMKo" role="1B3o_S" />
+      <node concept="10Oyi0" id="56MMu0AqMKq" role="3clF45" />
+      <node concept="37vLTG" id="56MMu0AqMKr" role="3clF46">
+        <property role="TrG5h" value="node" />
+        <node concept="3uibUv" id="56MMu0AqMKw" role="1tU5fm">
+          <ref role="3uigEE" to="jfki:~Node" resolve="Node" />
+        </node>
+      </node>
+      <node concept="3clFbS" id="56MMu0AqMKx" role="3clF47">
+        <node concept="3clFbF" id="56MMu0AqQuC" role="3cqZAp">
+          <node concept="2OqwBi" id="56MMu0AqQX$" role="3clFbG">
+            <node concept="2YIFZM" id="56MMu0AqQzB" role="2Oq$k0">
+              <ref role="37wK5l" to="e2lb:~String.valueOf(java.lang.Object):java.lang.String" resolve="valueOf" />
+              <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
+              <node concept="1rXfSq" id="56MMu0AqQGg" role="37wK5m">
+                <ref role="37wK5l" node="1R$Cm9qGRoH" resolve="symbol" />
+              </node>
+            </node>
+            <node concept="liA8E" id="56MMu0AqR_U" role="2OqNvi">
+              <ref role="37wK5l" to="e2lb:~String.compareTo(java.lang.String):int" resolve="compareTo" />
+              <node concept="2YIFZM" id="56MMu0AqRL4" role="37wK5m">
+                <ref role="37wK5l" to="e2lb:~String.valueOf(java.lang.Object):java.lang.String" resolve="valueOf" />
+                <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
+                <node concept="2OqwBi" id="56MMu0AqSaO" role="37wK5m">
+                  <node concept="37vLTw" id="56MMu0AqRRz" role="2Oq$k0">
+                    <ref role="3cqZAo" node="56MMu0AqMKr" resolve="node" />
+                  </node>
+                  <node concept="liA8E" id="56MMu0AqSsI" role="2OqNvi">
+                    <ref role="37wK5l" to="jfki:~Node.symbol()" resolve="symbol" />
+                  </node>
+                </node>
+              </node>
+            </node>
+          </node>
+        </node>
+      </node>
+      <node concept="2AHcQZ" id="56MMu0AqPPY" role="2AJF6D">
+        <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
+      </node>
+    </node>
+    <node concept="2tJIrI" id="56MMu0AqM0q" role="jymVt" />
     <node concept="3clFb_" id="1bm7a6EYD0x" role="jymVt">
       <property role="1EzhhJ" value="true" />
       <property role="TrG5h" value="copyRecursively" />
@@ -3445,9 +3477,6 @@
   <node concept="312cEu" id="uNmovXiEd4">
     <property role="TrG5h" value="Variable" />
     <node concept="3Tm1VV" id="uNmovXiEd5" role="1B3o_S" />
-    <node concept="3uibUv" id="uNmovXiEdE" role="EKbjA">
-      <ref role="3uigEE" to="jfki:~Var" resolve="Var" />
-    </node>
     <node concept="3uibUv" id="1bm7a6F1kuO" role="EKbjA">
       <ref role="3uigEE" node="1bm7a6EXvsP" resolve="ITreePart" />
       <node concept="3uibUv" id="1bm7a6F1oea" role="11_B2D">
@@ -3537,99 +3566,193 @@
       </node>
     </node>
     <node concept="2tJIrI" id="uNmovXiFhY" role="jymVt" />
-    <node concept="3clFb_" id="uNmovXiEdQ" role="jymVt">
+    <node concept="3clFb_" id="56MMu0Ark7d" role="jymVt">
       <property role="1EzhhJ" value="false" />
-      <property role="TrG5h" value="name" />
+      <property role="TrG5h" value="symbol" />
       <property role="DiZV1" value="false" />
       <property role="od$2w" value="false" />
-      <node concept="3Tm1VV" id="uNmovXiEdR" role="1B3o_S" />
-      <node concept="17QB3L" id="6SkxsMz$UXe" role="3clF45" />
-      <node concept="3clFbS" id="uNmovXiEdU" role="3clF47">
-        <node concept="3clFbF" id="2q_78a8ZTbq" role="3cqZAp">
-          <node concept="37vLTw" id="2q_78a9nVVq" role="3clFbG">
+      <node concept="3Tm1VV" id="56MMu0Ark7e" role="1B3o_S" />
+      <node concept="3uibUv" id="56MMu0Ark7g" role="3clF45">
+        <ref role="3uigEE" to="e2lb:~Object" resolve="Object" />
+      </node>
+      <node concept="3clFbS" id="56MMu0Ark7h" role="3clF47">
+        <node concept="3clFbF" id="56MMu0Arm4X" role="3cqZAp">
+          <node concept="37vLTw" id="56MMu0Arm4W" role="3clFbG">
             <ref role="3cqZAo" node="uNmovXiF5Z" resolve="name" />
           </node>
         </node>
       </node>
-      <node concept="2AHcQZ" id="uNmovXiFAo" role="2AJF6D">
+      <node concept="2AHcQZ" id="56MMu0ArkU3" role="2AJF6D">
         <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
       </node>
     </node>
-    <node concept="2tJIrI" id="uNmovXiFLt" role="jymVt" />
-    <node concept="3clFb_" id="uNmovXiEdX" role="jymVt">
+    <node concept="2tJIrI" id="56MMu0Arlqp" role="jymVt" />
+    <node concept="3clFb_" id="56MMu0Ark7k" role="jymVt">
       <property role="1EzhhJ" value="false" />
-      <property role="TrG5h" value="isTerm" />
+      <property role="TrG5h" value="children" />
       <property role="DiZV1" value="false" />
       <property role="od$2w" value="false" />
-      <node concept="3Tm1VV" id="uNmovXiEdY" role="1B3o_S" />
-      <node concept="10P_77" id="uNmovXiEe0" role="3clF45" />
-      <node concept="3clFbS" id="uNmovXiEe4" role="3clF47">
-        <node concept="3clFbF" id="uNmovXiEe6" role="3cqZAp">
-          <node concept="3clFbT" id="uNmovXiEe5" role="3clFbG" />
+      <node concept="3Tm1VV" id="56MMu0Ark7l" role="1B3o_S" />
+      <node concept="3uibUv" id="56MMu0Ark7n" role="3clF45">
+        <ref role="3uigEE" to="k7g3:~Collection" resolve="Collection" />
+        <node concept="3qUE_q" id="56MMu0Ark7o" role="11_B2D">
+          <node concept="3uibUv" id="56MMu0Ark7p" role="3qUE_r">
+            <ref role="3uigEE" to="jfki:~Node" resolve="Node" />
+          </node>
         </node>
       </node>
-      <node concept="2AHcQZ" id="uNmovXiGEG" role="2AJF6D">
+      <node concept="3clFbS" id="56MMu0Ark7s" role="3clF47">
+        <node concept="3clFbF" id="56MMu0Ark7u" role="3cqZAp">
+          <node concept="10Nm6u" id="56MMu0Ark7t" role="3clFbG" />
+        </node>
+      </node>
+      <node concept="2AHcQZ" id="56MMu0AronL" role="2AJF6D">
         <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
       </node>
     </node>
-    <node concept="2tJIrI" id="uNmovXiFXw" role="jymVt" />
-    <node concept="3clFb_" id="uNmovXiEe7" role="jymVt">
+    <node concept="2tJIrI" id="56MMu0Armi7" role="jymVt" />
+    <node concept="3clFb_" id="56MMu0Ark7v" role="jymVt">
       <property role="1EzhhJ" value="false" />
-      <property role="TrG5h" value="asTerm" />
+      <property role="TrG5h" value="get" />
       <property role="DiZV1" value="false" />
       <property role="od$2w" value="false" />
-      <node concept="3Tm1VV" id="uNmovXiEe8" role="1B3o_S" />
-      <node concept="3uibUv" id="uNmovXiEea" role="3clF45">
-        <ref role="3uigEE" to="jfki:~Term" resolve="Term" />
+      <node concept="3Tm1VV" id="56MMu0Ark7w" role="1B3o_S" />
+      <node concept="3uibUv" id="56MMu0Ark7y" role="3clF45">
+        <ref role="3uigEE" to="jfki:~Node" resolve="Node" />
       </node>
-      <node concept="3clFbS" id="uNmovXiEee" role="3clF47">
-        <node concept="YS8fn" id="uNmovXiG9A" role="3cqZAp">
-          <node concept="2ShNRf" id="uNmovXiGbq" role="YScLw">
-            <node concept="1pGfFk" id="uNmovXiGD5" role="2ShVmc">
-              <ref role="37wK5l" to="e2lb:~IllegalStateException.&lt;init&gt;()" resolve="IllegalStateException" />
+      <node concept="3clFbS" id="56MMu0Ark7_" role="3clF47">
+        <node concept="3clFbF" id="56MMu0ArpIO" role="3cqZAp">
+          <node concept="Xjq3P" id="56MMu0ArpIN" role="3clFbG" />
+        </node>
+      </node>
+      <node concept="2AHcQZ" id="56MMu0ArpbU" role="2AJF6D">
+        <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
+      </node>
+    </node>
+    <node concept="2tJIrI" id="56MMu0AroSn" role="jymVt" />
+    <node concept="3clFb_" id="56MMu0Ark7C" role="jymVt">
+      <property role="1EzhhJ" value="false" />
+      <property role="TrG5h" value="is" />
+      <property role="DiZV1" value="false" />
+      <property role="od$2w" value="false" />
+      <node concept="3Tm1VV" id="56MMu0Ark7D" role="1B3o_S" />
+      <node concept="37vLTG" id="56MMu0Ark7E" role="3clF46">
+        <property role="TrG5h" value="kind" />
+        <property role="3TUv4t" value="false" />
+        <node concept="3uibUv" id="56MMu0Ark7F" role="1tU5fm">
+          <ref role="3uigEE" to="jfki:~Node.Kind" resolve="Node.Kind" />
+        </node>
+      </node>
+      <node concept="10P_77" id="56MMu0Ark7H" role="3clF45" />
+      <node concept="3clFbS" id="56MMu0Ark7K" role="3clF47">
+        <node concept="3clFbF" id="56MMu0ArqpV" role="3cqZAp">
+          <node concept="3clFbC" id="56MMu0ArqJ4" role="3clFbG">
+            <node concept="37vLTw" id="56MMu0ArqYY" role="3uHU7w">
+              <ref role="3cqZAo" node="56MMu0Ark7E" resolve="kind" />
+            </node>
+            <node concept="Rm8GO" id="56MMu0ArqCS" role="3uHU7B">
+              <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+              <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
             </node>
           </node>
         </node>
       </node>
-      <node concept="2AHcQZ" id="uNmovXiGQp" role="2AJF6D">
+      <node concept="2AHcQZ" id="56MMu0ArrcS" role="2AJF6D">
         <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
       </node>
     </node>
-    <node concept="2tJIrI" id="uNmovXiH1I" role="jymVt" />
-    <node concept="3clFb_" id="uNmovXiEeh" role="jymVt">
+    <node concept="2tJIrI" id="56MMu0ArpJb" role="jymVt" />
+    <node concept="3clFb_" id="56MMu0Ark7N" role="jymVt">
       <property role="1EzhhJ" value="false" />
-      <property role="TrG5h" value="isVar" />
+      <property role="TrG5h" value="compareTo" />
       <property role="DiZV1" value="false" />
-      <property role="od$2w" value="false" />
-      <node concept="3Tm1VV" id="uNmovXiEei" role="1B3o_S" />
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-          <node concept="3clFbT" id="uNmovXiHe1" role="3clFbG">
-            <property role="3clFbU" value="true" />
+      <property role="IEkAT" value="false" />
+      <node concept="3Tm1VV" id="56MMu0Ark7O" role="1B3o_S" />
+      <node concept="10Oyi0" id="56MMu0Ark7Q" role="3clF45" />
+      <node concept="37vLTG" id="56MMu0Ark7R" role="3clF46">
+        <property role="TrG5h" value="that" />
+        <node concept="3uibUv" id="56MMu0Ark7Z" role="1tU5fm">
+          <ref role="3uigEE" to="jfki:~Node" resolve="Node" />
+        </node>
+      </node>
+      <node concept="3clFbS" id="56MMu0Ark80" role="3clF47">
+        <node concept="3clFbJ" id="56MMu0ArxkS" role="3cqZAp">
+          <node concept="3clFbS" id="56MMu0ArxkT" role="3clFbx">
+            <node concept="3cpWs6" id="56MMu0ArxkU" role="3cqZAp">
+              <node concept="2OqwBi" id="56MMu0ArxkV" role="3cqZAk">
+                <node concept="2YIFZM" id="56MMu0ArxkW" role="2Oq$k0">
+                  <ref role="37wK5l" to="e2lb:~String.valueOf(java.lang.Object):java.lang.String" resolve="valueOf" />
+                  <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
+                  <node concept="2OqwBi" id="56MMu0ArxkX" role="37wK5m">
+                    <node concept="Xjq3P" id="56MMu0ArxkY" role="2Oq$k0" />
+                    <node concept="liA8E" id="56MMu0ArxkZ" role="2OqNvi">
+                      <ref role="37wK5l" to="e2lb:~Object.getClass():java.lang.Class" resolve="getClass" />
+                    </node>
+                  </node>
+                </node>
+                <node concept="liA8E" id="56MMu0Arxl0" role="2OqNvi">
+                  <ref role="37wK5l" to="e2lb:~String.compareTo(java.lang.String):int" resolve="compareTo" />
+                  <node concept="2YIFZM" id="56MMu0Arxl1" role="37wK5m">
+                    <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
+                    <ref role="37wK5l" to="e2lb:~String.valueOf(java.lang.Object):java.lang.String" resolve="valueOf" />
+                    <node concept="2OqwBi" id="56MMu0Arxl2" role="37wK5m">
+                      <node concept="37vLTw" id="56MMu0Arxl3" role="2Oq$k0">
+                        <ref role="3cqZAo" node="56MMu0Ark7R" resolve="that" />
+                      </node>
+                      <node concept="liA8E" id="56MMu0Arxl4" role="2OqNvi">
+                        <ref role="37wK5l" to="e2lb:~Object.getClass():java.lang.Class" resolve="getClass" />
+                      </node>
+                    </node>
+                  </node>
+                </node>
+              </node>
+            </node>
+          </node>
+          <node concept="3y3z36" id="56MMu0Arxl5" role="3clFbw">
+            <node concept="2OqwBi" id="56MMu0Arxl6" role="3uHU7B">
+              <node concept="37vLTw" id="56MMu0Arxl7" role="2Oq$k0">
+                <ref role="3cqZAo" node="56MMu0Ark7R" resolve="that" />
+              </node>
+              <node concept="liA8E" id="56MMu0Arxl8" role="2OqNvi">
+                <ref role="37wK5l" to="e2lb:~Object.getClass():java.lang.Class" resolve="getClass" />
+              </node>
+            </node>
+            <node concept="2OqwBi" id="56MMu0Arxl9" role="3uHU7w">
+              <node concept="Xjq3P" id="56MMu0Arxla" role="2Oq$k0" />
+              <node concept="liA8E" id="56MMu0Arxlb" role="2OqNvi">
+                <ref role="37wK5l" to="e2lb:~Object.getClass():java.lang.Class" resolve="getClass" />
+              </node>
+            </node>
+          </node>
+        </node>
+        <node concept="3clFbF" id="56MMu0AruF$" role="3cqZAp">
+          <node concept="2OqwBi" id="56MMu0AruF_" role="3clFbG">
+            <node concept="2YIFZM" id="56MMu0AruFA" role="2Oq$k0">
+              <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
+              <ref role="37wK5l" to="e2lb:~String.valueOf(java.lang.Object):java.lang.String" resolve="valueOf" />
+              <node concept="1rXfSq" id="56MMu0AruFB" role="37wK5m">
+                <ref role="37wK5l" node="56MMu0Ark7d" resolve="symbol" />
+              </node>
+            </node>
+            <node concept="liA8E" id="56MMu0AruFC" role="2OqNvi">
+              <ref role="37wK5l" to="e2lb:~String.compareTo(java.lang.String):int" resolve="compareTo" />
+              <node concept="2YIFZM" id="56MMu0AruFD" role="37wK5m">
+                <ref role="37wK5l" to="e2lb:~String.valueOf(java.lang.Object):java.lang.String" resolve="valueOf" />
+                <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
+                <node concept="2OqwBi" id="56MMu0AruFE" role="37wK5m">
+                  <node concept="37vLTw" id="56MMu0AruFF" role="2Oq$k0">
+                    <ref role="3cqZAo" node="56MMu0Ark7R" resolve="that" />
+                  </node>
+                  <node concept="liA8E" id="56MMu0AruFG" role="2OqNvi">
+                    <ref role="37wK5l" to="jfki:~Node.symbol()" resolve="symbol" />
+                  </node>
+                </node>
+              </node>
+            </node>
           </node>
         </node>
       </node>
-      <node concept="2AHcQZ" id="uNmovXiHer" role="2AJF6D">
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-    <node concept="2tJIrI" id="uNmovXiHpU" role="jymVt" />
-    <node concept="3clFb_" id="uNmovXiEer" role="jymVt">
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-      <property role="TrG5h" value="asVar" />
-      <property role="DiZV1" value="false" />
-      <property role="od$2w" value="false" />
-      <node concept="3Tm1VV" id="uNmovXiEes" role="1B3o_S" />
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-      <node concept="3clFbS" id="uNmovXiEey" role="3clF47">
-        <node concept="3clFbF" id="uNmovXiHLX" role="3cqZAp">
-          <node concept="Xjq3P" id="uNmovXiHLW" role="3clFbG" />
-        </node>
-      </node>
-      <node concept="2AHcQZ" id="uNmovXiHAk" role="2AJF6D">
+      <node concept="2AHcQZ" id="56MMu0ArrI9" role="2AJF6D">
         <ref role="2AI5Lk" to="e2lb:~Override" resolve="Override" />
       </node>
     </node>
@@ -3745,100 +3868,6 @@
       </node>
     </node>
     <node concept="2tJIrI" id="5s497VqILJV" role="jymVt" />
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-                    <node concept="37vLTw" id="uNmovXiMCz" role="10QFUP">
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-      <node concept="2AHcQZ" id="uNmovXiIc6" role="2AJF6D">
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       <property role="1EzhhJ" value="false" />
       <property role="TrG5h" value="equals" />
@@ -6372,18 +6401,22 @@
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             <node concept="3clFbF" id="47nvOnTUGR$" role="3cqZAp">
               <node concept="37vLTI" id="47nvOnTUH81" role="3clFbG">
-                <node concept="2OqwBi" id="47nvOnTUHP9" role="37vLTx">
-                  <node concept="AH0OO" id="47nvOnTUHt9" role="2Oq$k0">
-                    <node concept="37vLTw" id="47nvOnTUHAC" role="AHEQo">
-                      <ref role="3cqZAo" node="47nvOnTUEPz" resolve="i" />
+                <node concept="2YIFZM" id="31Jz$8c046D" role="37vLTx">
+                  <ref role="37wK5l" to="e2lb:~String.valueOf(java.lang.Object):java.lang.String" resolve="valueOf" />
+                  <ref role="1Pybhc" to="e2lb:~String" resolve="String" />
+                  <node concept="2OqwBi" id="47nvOnTUHP9" role="37wK5m">
+                    <node concept="AH0OO" id="47nvOnTUHt9" role="2Oq$k0">
+                      <node concept="37vLTw" id="47nvOnTUHAC" role="AHEQo">
+                        <ref role="3cqZAo" node="47nvOnTUEPz" resolve="i" />
+                      </node>
+                      <node concept="37vLTw" id="47nvOnTUHd1" role="AHHXb">
+                        <ref role="3cqZAo" node="47nvOnTUxZD" resolve="childrenArr" />
+                      </node>
                     </node>
-                    <node concept="37vLTw" id="47nvOnTUHd1" role="AHHXb">
-                      <ref role="3cqZAo" node="47nvOnTUxZD" resolve="childrenArr" />
+                    <node concept="liA8E" id="31Jz$8c06nf" role="2OqNvi">
+                      <ref role="37wK5l" node="56MMu0Ark7d" resolve="symbol" />
                     </node>
                   </node>
-                  <node concept="liA8E" id="47nvOnTUI6t" role="2OqNvi">
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                 <node concept="AH0OO" id="47nvOnTUGWb" role="37vLTJ">
                   <node concept="37vLTw" id="47nvOnTUGXk" role="AHEQo">
@@ -11754,8 +11787,12 @@
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               <ref role="3cqZAo" node="5s497VqXKRl" resolve="tbr" />
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-            <node concept="liA8E" id="7d$oK1$CYAZ" role="2OqNvi">
-              <ref role="37wK5l" to="jfki:~Node.isVar()" resolve="isVar" />
+            <node concept="liA8E" id="56MMu0ApUmr" role="2OqNvi">
+              <ref role="37wK5l" to="jfki:~Node.is(Kind)" resolve="is" />
+              <node concept="Rm8GO" id="56MMu0ApUms" role="37wK5m">
+                <ref role="1Px2BO" to="jfki:~Node.Kind" resolve="Node.Kind" />
+                <ref role="Rm8GQ" to="jfki:~Node.VAR" resolve="VAR" />
+              </node>
             </node>
           </node>
           <node concept="9aQIb" id="7d$oK1$CYEt" role="9aQIa">
@@ -13338,7 +13375,7 @@
                                     <ref role="3cqZAo" node="HdxW7q$dx9" resolve="var" />
                                   </node>
                                   <node concept="liA8E" id="HdxW7q$dxF" role="2OqNvi">
-                                    <ref role="37wK5l" node="uNmovXiEdQ" resolve="name" />
+                                    <ref role="37wK5l" node="56MMu0Ark7d" resolve="symbol" />
                                   </node>
                                 </node>
                                 <node concept="2OqwBi" id="HdxW7q$dxG" role="3uHU7B">
@@ -13350,8 +13387,8 @@
                                       <ref role="37wK5l" to="jfki:~Substitution.Binding.var()" resolve="var" />
                                     </node>
                                   </node>
-                                  <node concept="liA8E" id="HdxW7q$dxK" role="2OqNvi">
-                                    <ref role="37wK5l" to="jfki:~Var.name()" resolve="name" />
+                                  <node concept="liA8E" id="56MMu0Awf_S" role="2OqNvi">
+                                    <ref role="37wK5l" to="jfki:~Node.symbol()" resolve="symbol" />
                                   </node>
                                 </node>
                               </node>