--- a
+++ b/partyMod/src/S3Classes.c
@@ -0,0 +1,199 @@
+
+/**
+    S3 classes for dealing with nodes and splits
+    *\file S3Classes.c
+    *\author $Author$
+    *\date $Date$
+*/
+                
+#include "party.h"
+                
+void C_init_node(SEXP node, int nobs, int ninputs, int nsurr, int q) {
+
+    SEXP nodeID, weights, criterion, primarysplit, surrogatesplits, 
+         terminal, prediction;
+
+    if (LENGTH(node) < NODE_LENGTH)
+        error("node is not a list with at least %d elements", NODE_LENGTH);
+        
+    SET_VECTOR_ELT(node, S3_NODEID, nodeID = allocVector(INTSXP, 1));
+    if (nobs > 0) 
+        SET_VECTOR_ELT(node, S3_WEIGHTS, weights = allocVector(REALSXP, nobs));
+    else
+        SET_VECTOR_ELT(node, S3_WEIGHTS, R_NilValue);
+    SET_VECTOR_ELT(node, S3_SUMWEIGHTS, allocVector(REALSXP, 1));
+    SET_VECTOR_ELT(node, S3_CRITERION, 
+        criterion = allocVector(VECSXP, CRITERION_LENGTH));
+    /* teststats */
+    SET_VECTOR_ELT(criterion, S3_STATISTICS, allocVector(REALSXP, ninputs)); 
+    /* criterion, aka pvalues */
+    SET_VECTOR_ELT(criterion, S3_iCRITERION, allocVector(REALSXP, ninputs));
+    /* max(criterion) */
+    SET_VECTOR_ELT(criterion, S3_MAXCRITERION, allocVector(REALSXP, 1)); 
+    SET_VECTOR_ELT(node, S3_TERMINAL, terminal = allocVector(LGLSXP, 1));
+    INTEGER(terminal)[0] = 0;
+    SET_VECTOR_ELT(node, S3_PSPLIT, 
+        primarysplit = allocVector(VECSXP, SPLIT_LENGTH));
+    SET_VECTOR_ELT(node, S3_SSPLIT, 
+                   surrogatesplits = allocVector(VECSXP, nsurr));
+    SET_VECTOR_ELT(node, S3_PREDICTION, prediction = allocVector(REALSXP, q));
+
+}
+
+void S3set_nodeID(SEXP node, int nodeID) {
+    INTEGER(VECTOR_ELT(node, S3_NODEID))[0] = nodeID;
+}
+
+int S3get_nodeID(SEXP node) {
+    return(INTEGER(VECTOR_ELT(node, S3_NODEID))[0]);
+}
+
+SEXP S3get_nodeweights(SEXP node) {
+    SEXP ans;
+    
+    ans = VECTOR_ELT(node, S3_WEIGHTS);
+    if (ans == R_NilValue)
+        error("node has no weights element"); 
+    return(VECTOR_ELT(node, S3_WEIGHTS));
+}
+
+double S3get_sumweights(SEXP node) {
+    return(REAL(VECTOR_ELT(node, S3_SUMWEIGHTS))[0]);
+}
+
+SEXP S3get_teststat(SEXP node) {
+    return(VECTOR_ELT(VECTOR_ELT(node, S3_CRITERION), S3_STATISTICS));
+}
+
+SEXP S3get_criterion(SEXP node) {
+    return(VECTOR_ELT(VECTOR_ELT(node, S3_CRITERION), S3_iCRITERION));
+}
+
+SEXP S3get_maxcriterion(SEXP node) {
+    return(VECTOR_ELT(VECTOR_ELT(node, S3_CRITERION), S3_MAXCRITERION));
+}
+
+void S3set_nodeterminal(SEXP node) {
+    INTEGER(VECTOR_ELT(node, S3_TERMINAL))[0] = 1;
+}
+
+int S3get_nodeterminal(SEXP node) {
+    return(INTEGER(VECTOR_ELT(node, S3_TERMINAL))[0]);
+}
+
+SEXP S3get_primarysplit(SEXP node) {
+    return(VECTOR_ELT(node, S3_PSPLIT));
+}
+
+SEXP S3get_surrogatesplits(SEXP node) {
+    return(VECTOR_ELT(node, S3_SSPLIT));
+}
+
+SEXP S3get_prediction(SEXP node) {
+    return(VECTOR_ELT(node, S3_PREDICTION));
+}
+
+SEXP S3get_leftnode(SEXP node) {
+    return(VECTOR_ELT(node, S3_LEFT));
+}
+
+SEXP S3get_rightnode(SEXP node) {
+    return(VECTOR_ELT(node, S3_RIGHT));
+}
+
+void C_init_orderedsplit(SEXP split, int nobs) {
+    
+    SEXP variableID, splitpoint, splitstatistics, ordered, toleft;
+    
+    if (LENGTH(split) < SPLIT_LENGTH)
+        error("split is not a list with at least %d elements", SPLIT_LENGTH);
+        
+    SET_VECTOR_ELT(split, S3_VARIABLEID, 
+                   variableID = allocVector(INTSXP, 1));
+    SET_VECTOR_ELT(split, S3_ORDERED, 
+                    ordered = allocVector(LGLSXP, 1));
+    INTEGER(ordered)[0] = 1;
+    SET_VECTOR_ELT(split, S3_SPLITPOINT, 
+                   splitpoint = allocVector(REALSXP, 1));
+    if (nobs > 0)
+        SET_VECTOR_ELT(split, S3_SPLITSTATISTICS, 
+                       splitstatistics = allocVector(REALSXP, nobs));
+    else
+        SET_VECTOR_ELT(split, S3_SPLITSTATISTICS, R_NilValue);
+    SET_VECTOR_ELT(split, S3_TOLEFT, toleft = allocVector(INTSXP, 1));
+    INTEGER(toleft)[0] = 1;
+    SET_VECTOR_ELT(split, S3_TABLE, R_NilValue);
+}
+
+void C_init_nominalsplit(SEXP split, int nlevels, int nobs) {
+    
+    SEXP variableID, splitpoint, splitstatistics, ordered, toleft, table;
+    
+    if (LENGTH(split) < SPLIT_LENGTH)
+        error("split is not a list with at least %d elements", SPLIT_LENGTH);
+
+    SET_VECTOR_ELT(split, S3_VARIABLEID, variableID = allocVector(INTSXP, 1));
+    SET_VECTOR_ELT(split, S3_ORDERED, ordered = allocVector(LGLSXP, 1));
+    INTEGER(ordered)[0] = 0;
+    SET_VECTOR_ELT(split, S3_SPLITPOINT, 
+                   splitpoint = allocVector(INTSXP, nlevels));
+    if (nobs > 0)
+        SET_VECTOR_ELT(split, S3_SPLITSTATISTICS, 
+                       splitstatistics = allocVector(REALSXP, nobs));
+    else
+        SET_VECTOR_ELT(split, S3_SPLITSTATISTICS, R_NilValue);
+    SET_VECTOR_ELT(split, S3_TOLEFT, toleft = allocVector(INTSXP, 1));
+    INTEGER(toleft)[0] = 1;
+    SET_VECTOR_ELT(split, S3_TABLE, table = allocVector(INTSXP, nlevels));
+}
+
+void S3set_variableID(SEXP split, int variableID) {
+    INTEGER(VECTOR_ELT(split, S3_VARIABLEID))[0] = variableID;
+}
+
+int S3get_variableID(SEXP split) {
+    return(INTEGER(VECTOR_ELT(split, S3_VARIABLEID))[0]);
+}
+
+int S3is_ordered(SEXP split) {
+    return(INTEGER(VECTOR_ELT(split, S3_ORDERED))[0]);
+}
+
+void S3set_ordered(SEXP split) {
+    INTEGER(VECTOR_ELT(split, S3_ORDERED))[0] = 1;
+}
+
+void S3set_nominal(SEXP split) {
+    INTEGER(VECTOR_ELT(split, S3_ORDERED))[0] = 0;
+}
+
+int S3get_toleft(SEXP split) {
+    return(INTEGER(VECTOR_ELT(split, S3_TOLEFT))[0]);
+}
+
+void S3set_toleft(SEXP split, int left) {
+    /* <FIXME> use LOGICAL here? </FIXME> */
+    INTEGER(VECTOR_ELT(split, S3_TOLEFT))[0] = left;
+}
+
+SEXP S3get_splitpoint(SEXP split) {
+   return(VECTOR_ELT(split, S3_SPLITPOINT));
+}
+   
+SEXP S3get_splitstatistics(SEXP split) {
+   SEXP ans;
+   
+   ans = VECTOR_ELT(split, S3_SPLITSTATISTICS);
+   if (ans == R_NilValue)
+       error("split does not have a splitstatistics element");
+   return(ans);
+}
+
+SEXP S3get_table(SEXP split) {
+   SEXP ans;
+   
+   ans = VECTOR_ELT(split, S3_TABLE);
+   if (ans == R_NilValue)
+       error("split does not have a table element");
+   return(ans);
+}