diff --git a/src/musredit_qt5/mupp/PmuppScript.cpp b/src/musredit_qt5/mupp/PmuppScript.cpp
index 829637c8..9305b9a6 100644
--- a/src/musredit_qt5/mupp/PmuppScript.cpp
+++ b/src/musredit_qt5/mupp/PmuppScript.cpp
@@ -113,7 +113,7 @@ int PmuppScript::executeScript()
     } else if (cmd.startsWith("var")) {
       status = var_cmd(cmd);
     } else if (cmd.startsWith("col")) {
-      std::cout << "debug> will eventually handle linking of a variable to a collection ..." << std::endl;
+      // nothing to be done here, since var handles it internally
     } else {
       std::cerr << "**ERROR** found unkown script command '" << cmd.toLatin1().constData() << "'." << std::endl << std::endl;
       status = -2;
@@ -300,14 +300,32 @@ int PmuppScript::addX(const QString str)
     // clean up plot info first
     fPlotInfo.clear();
 
-    // make sure that label is found in ALL collections
+    // make sure that label is found in ALL collections, or in variables
+    // first check collections
+    bool foundInColl(true), foundInVar(true);
+    QString collName("");
     for (int i=0; i<fParamDataHandler->GetNoOfCollections(); i++) {
       coll = fParamDataHandler->GetCollection(i);
       if (!foundLabel(coll, label)) { // label not found
+        foundInColl = false;
+        collName = coll->GetName();
+        break;
+/* //as35
         std::cerr << std::endl << "**ERROR** couldn't find '" << label.toLatin1().constData() << "' in collection '" << coll->GetName().toLatin1().constData() << "'" << std::endl << std::endl;
         return -4;
+*/ //as35
       }
     }
+    // second check variables
+    if (!foundVariable(label)) { // label not found
+      foundInVar = false;
+    }
+    // make sure label(s) have been found
+    if (!foundInColl && !foundInVar) { // not all labels found, neither in collection nor variables.
+      std::cerr << std::endl << "**ERROR** couldn't find '" << label.toLatin1().constData() << "' in collection '" << collName.toLatin1().constData() << "'," << std::endl;
+      std::cerr << "          nor is it a defined variable" << std::endl << std::endl;
+      return -4;
+    }
 
     // resize fPlotInfo to the number of selections
     fPlotInfo.resize(fParamDataHandler->GetNoOfCollections());
@@ -318,15 +336,32 @@ int PmuppScript::addX(const QString str)
       fPlotInfo[i].xLabel = label;
     }
   } else { // a specific selection
-    // check that label is found in the selected collection
+    // check that label is found in the selected collection, or in variables
     coll = fParamDataHandler->GetCollection(fSelected);
     if (coll == 0) {
       std::cerr << std::endl << "**ERROR** in addX: selected collection couldn't be found ..." << std::endl << std::endl;
       return -3;
     }
+    // first check collection
+    bool foundInColl(true), foundInVar(true);
+    QString collName("");
     if (!foundLabel(coll, label)) { // label not found
+      foundInColl = false;
+      collName = coll->GetName();
+/* //as35
       std::cerr << std::endl << "**ERROR** couldn't find '" << label.toLatin1().constData() << "' in collection '" << coll->GetName().toLatin1().constData() << "'" << std::endl << std::endl;
       return -4;
+*/ //as35
+    }
+    // second check variables
+    if (!foundVariable(label)) { // label not found
+      foundInVar = false;
+    }
+    // make sure label(s) have been found
+    if (!foundInColl && !foundInVar) { // not all labels found, neither in collection nor variables.
+      std::cerr << std::endl << "**ERROR** couldn't find '" << label.toLatin1().constData() << "' in collection '" << collName.toLatin1().constData() << "'," << std::endl;
+      std::cerr << "          nor is it a defined variable" << std::endl << std::endl;
+      return -4;
     }
 
     // feed plot entry
@@ -362,16 +397,40 @@ int PmuppScript::addY(const QString str)
     std::cerr << std::endl << "**ERROR** in addY. addY called without previous 'select' command." << std::endl << std::endl;
     return -2;
   } else if (fSelected == -1) { // i.e. select ALL
-    // make sure that label(s) is/are found in ALL collections
+    // make sure that label(s) is/are found in ALL collections, or in variables
+    // first check collections
+    bool foundInColl(true), foundInVar(true);
+    int idx = -1;
+    QString collName("");
     for (int i=0; i<fParamDataHandler->GetNoOfCollections(); i++) {
       coll = fParamDataHandler->GetCollection(i);
       for (int j=0; j<label.size(); j++) {
         if (!foundLabel(coll, label[j])) { // label not found
+          foundInColl = false;
+          collName = coll->GetName();
+          idx = j;
+          break;
+/* //as35
           std::cerr << std::endl << "**ERROR** couldn't find '" << label[j].toLatin1().constData() << "' in collection '" << coll->GetName().toLatin1().constData() << "'" << std::endl << std::endl;
           return -4;
+*/ //as35
         }
       }
     }
+    // second check variables
+    for (int i=0; i<label.size(); i++) {
+      if (!foundVariable(label[i])) { // label not found
+        foundInVar = false;
+        idx = i;
+        break;
+      }
+    }
+    // make sure label(s) have been found
+    if (!foundInColl && !foundInVar) { // not all labels found, neither in collection nor variables.
+      std::cerr << std::endl << "**ERROR** couldn't find '" << label[idx].toLatin1().constData() << "' in collection '" << collName.toLatin1().constData() << "'," << std::endl;
+      std::cerr << "          nor is it a defined variable" << std::endl << std::endl;
+      return -4;
+    }
 
     // feed plot info with y-label(s)
     for (int i=0; i<fPlotInfo.size(); i++) {
@@ -381,19 +440,44 @@ int PmuppScript::addY(const QString str)
     // clear yLabel
     fPlotEntry.yLabel.clear();
 
-    // check that label is found in the selected collection
+    // check that label is found in the selected collection, or in the variables
     coll = fParamDataHandler->GetCollection(fSelected);
     if (coll == 0) {
       std::cerr << std::endl << "**ERROR** in addY: selected collection couldn't be found ..." << std::endl << std::endl;
       return -3;
     }
 
+    // first check specific collection
+    bool foundInColl(true), foundInVar(true);
+    int idx = -1;
+    QString collName("");
     for (int i=0; i<label.size(); i++) {
       if (!foundLabel(coll, label[i])) { // label not found
+        foundInColl = false;
+        collName = coll->GetName();
+        idx = i;
+        break;
+/* //as35
         std::cerr << std::endl << "**ERROR** couldn't find '" << label[i].toLatin1().constData() << "' in collection '" << coll->GetName().toLatin1().constData() << "'" << std::endl << std::endl;
         return -4;
+*/ //as35
       }
     }
+    // second check variables
+    for (int i=0; i<label.size(); i++) {
+      if (!foundVariable(label[i])) { // label not found
+        foundInVar = false;
+        idx = i;
+        break;
+      }
+    }
+    // make sure label(s) have been found
+    if (!foundInColl && !foundInVar) { // not all labels found, neither in collection nor variables.
+      std::cerr << std::endl << "**ERROR** couldn't find '" << label[idx].toLatin1().constData() << "' in collection '" << collName.toLatin1().constData() << "'," << std::endl;
+      std::cerr << "          nor is it a defined variable" << std::endl << std::endl;
+      return -4;
+    }
+
     fPlotEntry.yLabel = label;
 
     // add plot entry
@@ -517,6 +601,16 @@ int PmuppScript::macro(const QString str, const QString plotFln)
     // get collection name
     collName = fParamDataHandler->GetCollectionName(i);
     xx = fParamDataHandler->GetValues(collName, fPlotInfo[i].xLabel);
+    if (xx.size() == 0) { // it is a variable
+      int idx = getVarIndex(fPlotInfo[i].xLabel);
+      if (idx == -1) {
+        std::cerr << std::endl;
+        std::cerr << "**ERROR** Couldn't get x-label '" << fPlotInfo[i].xLabel.toLatin1().data() << "'." << std::endl;
+        std::cerr << "          This should never happens." << std::endl;
+        return -3;
+      }
+      xx = QVector<double>::fromStdVector(fVarHandler[idx].getValues());
+    }
     // get x-axis min/max
     minMax(xx, x_min, x_max);
     if (count==0) {
@@ -533,6 +627,18 @@ int PmuppScript::macro(const QString str, const QString plotFln)
       yy = fParamDataHandler->GetValues(collName, fPlotInfo[i].yLabel[j]);
       yyPosErr = fParamDataHandler->GetPosErr(collName, fPlotInfo[i].yLabel[j]);
       yyNegErr = fParamDataHandler->GetNegErr(collName, fPlotInfo[i].yLabel[j]);
+      if (yy.size() == 0) { // it's a variable
+        int idx = getVarIndex(fPlotInfo[i].yLabel[j]);
+        if (idx == -1) {
+          std::cerr << std::endl;
+          std::cerr << "**ERROR** Couldn't get y-label '" << fPlotInfo[i].yLabel[j].toLatin1().data() << "'." << std::endl;
+          std::cerr << "          This should never happens." << std::endl;
+          return -3;
+        }
+        yy = QVector<double>::fromStdVector(fVarHandler[idx].getValues());
+        yyPosErr = QVector<double>::fromStdVector(fVarHandler[idx].getErrors());
+        yyNegErr = QVector<double>::fromStdVector(fVarHandler[idx].getErrors());
+      }
       // get y-axis min/max
       minMax(yy, y_min, y_max);
       if (count==0) {
@@ -684,7 +790,7 @@ int PmuppScript::var_cmd(const QString str)
   if (idx == -1) // var not linked to collection, ignore it
     return 0;
 
-  // check for the related error variable if present
+  // check if the related error variable is present
   QString varErr = QString("%1%2").arg(tok[1]).arg("Err");
   QString varErrCmd("");
   for (int i=0; i<fScript.size(); i++) {
@@ -700,7 +806,9 @@ int PmuppScript::var_cmd(const QString str)
     parse_str += varErrCmd.toLatin1().data();
   }
 
-  PVarHandler varHandler(fParamDataHandler->GetCollection(idx), parse_str);
+  PVarHandler varHandler(fParamDataHandler->GetCollection(idx), parse_str, tok[1].toLatin1().data());
+  if (!varHandler.isValid())
+    return 1;
   fVarHandler.push_back(varHandler);
 
   return 0;
@@ -725,6 +833,44 @@ bool PmuppScript::foundLabel(PmuppCollection *coll, const QString label)
   return result;
 }
 
+//--------------------------------------------------------------------------
+/**
+ * @brief PmuppScript::foundVariable
+ * @param var
+ * @return
+ */
+bool PmuppScript::foundVariable(const QString var)
+{
+  bool result = false;
+  for (int i=0; i<fVarHandler.size(); i++) {
+    if (!fVarHandler[i].getVarName().compare(var)) {
+      result = true;
+      break;
+    }
+  }
+
+  return result;
+}
+
+//--------------------------------------------------------------------------
+/**
+ * @brief PmuppScript::getVarIndex
+ * @param var
+ * @return
+ */
+int PmuppScript::getVarIndex(const QString var)
+{
+  int idx = -1;
+  for (int i=0; i<fVarHandler.size(); i++) {
+    if (!fVarHandler[i].getVarName().compare(var)) {
+      idx = i;
+      break;
+    }
+  }
+
+  return idx;
+}
+
 //--------------------------------------------------------------------------
 /**
  * @brief PmuppScript::minMax
diff --git a/src/musredit_qt5/mupp/PmuppScript.h b/src/musredit_qt5/mupp/PmuppScript.h
index 44f8a716..033e6965 100644
--- a/src/musredit_qt5/mupp/PmuppScript.h
+++ b/src/musredit_qt5/mupp/PmuppScript.h
@@ -89,6 +89,8 @@ class PmuppScript : public QObject
     QVector<PVarHandler> fVarHandler;
 
     bool foundLabel(PmuppCollection *coll, const QString label);
+    bool foundVariable(const QString var);
+    int  getVarIndex(const QString var);
     void minMax(QVector<double> dvec, double &min, double &max);
     QString getNicerLabel(const QString label);
 
diff --git a/src/musredit_qt5/mupp/examples/sigmaSC-vs-temp.txt b/src/musredit_qt5/mupp/examples/sigmaSC-vs-temp.txt
index 5d565e40..f19ef5ad 100644
--- a/src/musredit_qt5/mupp/examples/sigmaSC-vs-temp.txt
+++ b/src/musredit_qt5/mupp/examples/sigmaSC-vs-temp.txt
@@ -5,22 +5,21 @@ loadPath ./
 load YBCO-40nm-FC-E3p8keV-B10mT-Tscan.db  # collection 0
 load YBCO-40nm-FC-E3p8keV-B150mT-Tscan.db # collection 1
 
-# define the variables (on this level the parsing will be done)
 # B=10mT
-var quatsch
 var SigmaSC_10 = pow(abs(pow($Sigma,2.0)-pow(0.11,2.0)), 0.5) # 0.11 (1/us) is the nuclear contribution (T>Tc)
 var SigmaSC_10Err = pow(pow($Sigma*$SigmaErr,2.0)+pow(0.11*0.0025,2.0), 0.5)/$SigmaSC_10
 # B=150mT
 var SigmaSC_150 = pow(abs(pow($Sigma,2.0)-pow(0.075,2.0)), 0.5) # 0.075 (1/us) is the nuclear contribution (T>Tc)
 var SigmaSC_150Err = pow(pow($Sigma*$SigmaErr,2.0)+pow(0.075*0.0025,2.0), 0.5)/$SigmaSC_150
 
-# link variables to collection (on this level the semantic checks will be done)
 col 0 : SigmaSC_10    # error variable SigmaSC_10Err doesn't need to be given, it is automatically linked to SigmaSC_10
 col 1 : SigmaSC_150
 
+norm
+
 select 0
 x dataT
-y SigmaSC_10  # (on this level the evaluation will be done)
+y SigmaSC_10
 
 select 1
 x dataT
diff --git a/src/musredit_qt5/mupp/var/include/PVarHandler.h b/src/musredit_qt5/mupp/var/include/PVarHandler.h
index 02277ec4..94beac1a 100644
--- a/src/musredit_qt5/mupp/var/include/PVarHandler.h
+++ b/src/musredit_qt5/mupp/var/include/PVarHandler.h
@@ -36,24 +36,32 @@
 #include <QString>
 
 #include "Pmupp.h"
-#include <PAst.hpp>
+#include "PAst.hpp"
+#include "PProgram.hpp"
 
 class PVarHandler {
   public:
-    PVarHandler(PmuppCollection *coll, std::string parse_str);
+    PVarHandler(PmuppCollection *coll, std::string parse_str, std::string var_name);
 
     bool isValid() { return fIsValid; }
+    QString getVarName() { return QString(fVarName.c_str()); }
     std::vector<double> getValues();
     std::vector<double> getErrors();
 
   private:
     PmuppCollection *fColl; ///< collection need for parsing and evaluation
     std::string fParseStr; ///< the variable input to be parsed
+    std::string fVarName;  ///< variable name
+    mupp::prog::PVarHandler fVar; ///< values of the evaluation
 
     bool fIsValid;
     mupp::ast::statement_list fAst; ///< the AST
 
     void injectPredefVariables();
+
+    std::string getVarName(int idx);
+    std::vector<double> getData(int idx);
+    std::vector<double> getDataErr(int idx);
 };
 
 #endif //_PVARHANDLER_H_
diff --git a/src/musredit_qt5/mupp/var/src/CMakeLists.txt b/src/musredit_qt5/mupp/var/src/CMakeLists.txt
index ed93922e..90abf78f 100644
--- a/src/musredit_qt5/mupp/var/src/CMakeLists.txt
+++ b/src/musredit_qt5/mupp/var/src/CMakeLists.txt
@@ -1,4 +1,7 @@
 target_sources(mupp
   PRIVATE 
     ${CMAKE_CURRENT_LIST_DIR}/PVarHandler.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/PExpression.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/PProgram.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/PStatement.cpp
 )
diff --git a/src/musredit_qt5/mupp/var/src/PVarHandler.cpp b/src/musredit_qt5/mupp/var/src/PVarHandler.cpp
index 62e134df..afe9d3a3 100644
--- a/src/musredit_qt5/mupp/var/src/PVarHandler.cpp
+++ b/src/musredit_qt5/mupp/var/src/PVarHandler.cpp
@@ -31,22 +31,54 @@
 
 #include "PVarHandler.h"
 
-/*
 #include "PSkipper.hpp"
 #include "PErrorHandler.hpp"
 #include "PStatement.hpp"
-#include "PAstDump.hpp"
 #include "PProgram.hpp"
-*/
 
 //--------------------------------------------------------------------------
 /**
  * @brief PVarHandler::PVarHandler
  */
-PVarHandler::PVarHandler(PmuppCollection *coll, std::string parse_str) :
-  fColl(coll), fParseStr(parse_str), fIsValid(false)
+PVarHandler::PVarHandler(PmuppCollection *coll, std::string parse_str, std::string var_name) :
+  fColl(coll), fParseStr(parse_str), fVarName(var_name), fIsValid(false)
 {
   injectPredefVariables();
+
+  typedef std::string::const_iterator iterator_type;
+  iterator_type iter = fParseStr.begin();
+  iterator_type end = fParseStr.end();
+
+  mupp::PErrorHandler<iterator_type> error_handler(iter, end);   // the error handler
+  mupp::parser::PStatement<iterator_type> parser(error_handler); // the parser
+  mupp::prog::PProgram prog(error_handler); // our compiler, and exec
+  mupp::parser::PSkipper<iterator_type> skipper; // the skipper parser
+
+  // perform the parsing
+  bool success = phrase_parse(iter, end, parser, skipper, fAst);
+  if (success && iter == end) {
+    if (prog(fAst)) { // semantic analysis
+      std::vector<double> data, dataErr;
+      for (unsigned int i=0; i<fColl->GetRun(0).GetNoOfParam(); i++) {
+        data = getData(i);
+        dataErr = getDataErr(i);
+        prog.add_predef_var_values(getVarName(i), data, dataErr);
+      }
+      mupp::prog::PProgEval eval(prog.getVars()); // setup evaluation stage
+      eval(fAst); // evaluate stuff
+
+      // keep data
+      bool ok;
+      fVar = eval.getVar(fVarName, ok);
+      if (!ok) {
+        std::cerr << "**ERROR** evalution failed..." << std::endl;
+        fIsValid = false;
+      }
+    }
+    fIsValid = true;
+  } else {
+    std::cerr << "**ERROR** parsing failed..." << std::endl;
+  }
 }
 
 //--------------------------------------------------------------------------
@@ -56,9 +88,11 @@ PVarHandler::PVarHandler(PmuppCollection *coll, std::string parse_str) :
  */
 std::vector<double> PVarHandler::getValues()
 {
-  std::vector<double> result;
+  std::vector<double> data;
+  if (fIsValid)
+    data = fVar.GetValue();
 
-  return result;
+  return data;
 }
 
 //--------------------------------------------------------------------------
@@ -68,9 +102,11 @@ std::vector<double> PVarHandler::getValues()
  */
 std::vector<double> PVarHandler::getErrors()
 {
-  std::vector<double> result;
+  std::vector<double> data;
+  if (fIsValid)
+    data = fVar.GetError();
 
-  return result;
+  return data;
 }
 
 //--------------------------------------------------------------------------
@@ -83,8 +119,9 @@ void PVarHandler::injectPredefVariables()
   mupp::ast::variable_declaration var;
 
   std::string varName, errVarName;
-  for (int i=0; i<fColl->GetNoOfRuns(); i++) {
-    varName = fColl->GetRun(i).GetName().toLatin1().data();
+  PmuppRun run = fColl->GetRun(0);
+  for (int i=0; i<run.GetNoOfParam(); i++) {
+    varName = run.GetParam(i).GetName().toLatin1().data();
     errVarName = varName + "Err";
     // inject err_name
     var.lhs.name = errVarName;
@@ -96,3 +133,68 @@ void PVarHandler::injectPredefVariables()
     fAst.push_front(var_stat);
   }
 }
+
+//--------------------------------------------------------------------------
+/**
+ * @brief PVarHandler::getVarName
+ * @param idx
+ * @return
+ */
+std::string PVarHandler::getVarName(int idx)
+{
+  std::string name("??");
+
+  // make sure idx is in range
+  if (idx >= fColl->GetRun(0).GetNoOfParam())
+    return name;
+
+  return fColl->GetRun(0).GetParam(idx).GetName().toLatin1().data();
+}
+
+//--------------------------------------------------------------------------
+/**
+ * @brief PVarHandler::getData
+ * @param idx
+ * @return
+ */
+std::vector<double> PVarHandler::getData(int idx)
+{
+  std::vector<double> data;
+
+  // make sure idx is in range
+  if (idx >= fColl->GetRun(0).GetNoOfParam())
+    return data;
+
+  double dval;
+  for (int i=0; i<fColl->GetNoOfRuns(); i++) {
+    dval = fColl->GetRun(i).GetParam(idx).GetValue();
+    data.push_back(dval);
+  }
+
+  return data;
+}
+
+//--------------------------------------------------------------------------
+/**
+ * @brief PVarHandler::getDataErr
+ * @param idx
+ * @return
+ */
+std::vector<double> PVarHandler::getDataErr(int idx)
+{
+  std::vector<double> err;
+
+  // make sure idx is in range
+  if (idx >= fColl->GetRun(0).GetNoOfParam())
+    return err;
+
+  double dvalPos, dvalNeg;
+  for (int i=0; i<fColl->GetNoOfRuns(); i++) {
+    dvalPos = fColl->GetRun(i).GetParam(idx).GetPosErr();
+    dvalNeg = fColl->GetRun(i).GetParam(idx).GetNegErr();
+    dvalPos = sqrt(fabs(dvalPos*dvalNeg)); // geometric mean of pos/neg error
+    err.push_back(dvalPos);
+  }
+
+  return err;
+}