diff --git a/src/musredit_qt5/mupp/CMakeLists.txt b/src/musredit_qt5/mupp/CMakeLists.txt
index da3fd196..7f9619fd 100644
--- a/src/musredit_qt5/mupp/CMakeLists.txt
+++ b/src/musredit_qt5/mupp/CMakeLists.txt
@@ -42,7 +42,7 @@ set(GENERATED_HEADER_FILES
 )
 set_property(SOURCE mupp_version.h PROPERTY SKIP_AUTOMOC ON) # needed for cmake 3.x
 
-set(SOURCE_FILES
+set(MUPP_SOURCE_FILES
   mupp.cpp 
   PmuppAdmin.cpp 
   Pmupp.cpp
@@ -54,13 +54,24 @@ set(SOURCE_FILES
 if (APPLE)
   set(RESOURCE_FILES icons/mupp.icns)
   add_executable(mupp 
-     MACOSX_BUNDLE ${GENERATED_HEADER_FILES} ${SOURCE_FILES} 
+     MACOSX_BUNDLE ${GENERATED_HEADER_FILES} ${MUPP_SOURCE_FILES} 
      qrc_mupp.cpp ${RESOURCE_FILES}
   )
 else (APPLE)
-  add_executable(mupp ${GENERATED_HEADER_FILES} ${SOURCE_FILES} qrc_mupp.cpp)
+  add_executable(mupp ${GENERATED_HEADER_FILES} ${MUPP_SOURCE_FILES} qrc_mupp.cpp)
 endif (APPLE)
 
+#--- add the variable related sources -----------------------------------------
+add_subdirectory(var)
+
+#--- add the necessary header includes ----------------------------------------
+target_include_directories(mupp 
+  BEFORE PRIVATE
+    $<BUILD_INTERFACE:${Boost_INCLUDE_DIR}>
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/var/include>
+)
+
 #--- use the Widgets and XML modules from Qt5 ---------------------------------
 target_link_libraries(mupp Qt5::Widgets Qt5::Xml)
 
diff --git a/src/musredit_qt5/mupp/PmuppScript.h b/src/musredit_qt5/mupp/PmuppScript.h
index dbb4a996..e732251d 100644
--- a/src/musredit_qt5/mupp/PmuppScript.h
+++ b/src/musredit_qt5/mupp/PmuppScript.h
@@ -35,6 +35,7 @@
 
 #include "PmuppAdmin.h"
 #include "Pmupp.h"
+#include "PVarHandler.h"
 
 typedef struct {
   int collIdx;
@@ -84,6 +85,8 @@ class PmuppScript : public QObject
     QString fLoadPath;
     QString fSavePath;
 
+    QVector<PVarHandler> fVarHandler;
+
     bool foundLabel(PmuppCollection *coll, const QString label);
     void minMax(QVector<double> dvec, double &min, double &max);
     QString getNicerLabel(const QString label);
diff --git a/src/musredit_qt5/mupp/var/CMakeLists.txt b/src/musredit_qt5/mupp/var/CMakeLists.txt
new file mode 100644
index 00000000..febd4f0a
--- /dev/null
+++ b/src/musredit_qt5/mupp/var/CMakeLists.txt
@@ -0,0 +1 @@
+add_subdirectory(src)
diff --git a/src/musredit_qt5/mupp/var/include/PAst.hpp b/src/musredit_qt5/mupp/var/include/PAst.hpp
new file mode 100644
index 00000000..c2afa127
--- /dev/null
+++ b/src/musredit_qt5/mupp/var/include/PAst.hpp
@@ -0,0 +1,197 @@
+/***************************************************************************
+
+  PAst.hpp
+
+  Author: Andreas Suter
+  e-mail: andreas.suter@psi.ch
+
+  Based on Joel de Guzman example on calc7,
+  see https://github.com/boostorg/spirit
+
+***************************************************************************/
+
+/***************************************************************************
+ *   Copyright (C) 2020 by Andreas Suter                                   *
+ *   andreas.suter@psi.ch                                                  *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
+ ***************************************************************************/
+
+#ifndef _PAST_HPP_
+#define _PAST_HPP_
+
+#include <boost/config/warning_disable.hpp>
+#include <boost/variant/recursive_variant.hpp>
+#include <boost/fusion/include/adapt_struct.hpp>
+#include <boost/fusion/include/io.hpp>
+#include <boost/optional.hpp>
+#include <list>
+
+namespace mupp { namespace ast
+{
+    ///////////////////////////////////////////////////////////////////////////
+    //  The AST
+    ///////////////////////////////////////////////////////////////////////////
+    struct tagged
+    {
+      int id; // Used to annotate the AST with the iterator position.
+              // This id is used as a key to a map<int, Iterator>
+              // (not really part of the AST.)
+    };
+
+    enum optoken
+    {
+      op_plus,
+      op_minus,
+      op_times,
+      op_divide,
+      op_positive,
+      op_negative,
+    };
+
+    enum funid
+    {
+      fun_max,
+      fun_min,
+      fun_abs,
+      fun_sin,
+      fun_cos,
+      fun_tan,
+      fun_exp,
+      fun_log,
+      fun_ln
+    };
+
+    struct nil {};
+    struct unary;
+    struct expression;
+    struct function;
+    struct power;
+
+    struct variable : tagged
+    {
+      variable(std::string const& name = "") : name(name) {}
+      std::string name;
+    };
+
+    typedef boost::variant<
+            nil
+          , double
+          , variable
+          , boost::recursive_wrapper<function>
+          , boost::recursive_wrapper<power>
+          , boost::recursive_wrapper<unary>
+          , boost::recursive_wrapper<expression>
+        >
+    operand;
+
+    struct unary
+    {
+      optoken operator_;
+      operand operand_;
+    };
+
+    struct operation
+    {
+      optoken operator_;
+      operand operand_;
+    };
+
+    struct expression
+    {
+      operand first;
+      std::list<operation> rest;
+    };
+
+    struct function
+    {
+      funid func_id;
+      expression arg;
+    };
+
+    struct power
+    {
+      expression base;
+      expression pow;
+    };
+
+    struct assignment
+    {
+      variable lhs;
+      expression rhs;
+    };
+
+    struct variable_declaration
+    {
+      variable lhs;
+      boost::optional<expression> rhs;
+    };
+
+    typedef boost::variant<
+            variable_declaration
+          , assignment>
+    statement;
+
+    typedef std::list<statement> statement_list;
+
+    // print functions for debugging
+    inline std::ostream& operator<<(std::ostream& out, nil) { out << "nil"; return out; }
+    inline std::ostream& operator<<(std::ostream& out, variable const& var) { out << var.name; return out; }
+}}
+
+BOOST_FUSION_ADAPT_STRUCT(
+    mupp::ast::unary,
+    (mupp::ast::optoken, operator_)
+    (mupp::ast::operand, operand_)
+)
+
+BOOST_FUSION_ADAPT_STRUCT(
+    mupp::ast::operation,
+    (mupp::ast::optoken, operator_)
+    (mupp::ast::operand, operand_)
+)
+
+BOOST_FUSION_ADAPT_STRUCT(
+    mupp::ast::expression,
+    (mupp::ast::operand, first)
+    (std::list<mupp::ast::operation>, rest)
+)
+
+BOOST_FUSION_ADAPT_STRUCT(
+    mupp::ast::function,
+    (mupp::ast::funid, func_id)
+    (mupp::ast::expression, arg)
+)
+
+BOOST_FUSION_ADAPT_STRUCT(
+    mupp::ast::power,
+    (mupp::ast::expression, base)
+    (mupp::ast::expression, pow)
+)
+
+BOOST_FUSION_ADAPT_STRUCT(
+    mupp::ast::variable_declaration,
+    (mupp::ast::variable, lhs)
+    (boost::optional<mupp::ast::expression>, rhs)
+)
+
+BOOST_FUSION_ADAPT_STRUCT(
+    mupp::ast::assignment,
+    (mupp::ast::variable, lhs)
+    (mupp::ast::expression, rhs)
+)
+
+#endif // _PAST_HPP_
diff --git a/src/musredit_qt5/mupp/var/include/PVarHandler.h b/src/musredit_qt5/mupp/var/include/PVarHandler.h
new file mode 100644
index 00000000..98f607fd
--- /dev/null
+++ b/src/musredit_qt5/mupp/var/include/PVarHandler.h
@@ -0,0 +1,55 @@
+/***************************************************************************
+
+  PVarHandler.h
+
+  Author: Andreas Suter
+  e-mail: andreas.suter@psi.ch
+
+***************************************************************************/
+
+/***************************************************************************
+ *   Copyright (C) 2007-2020 by Andreas Suter                              *
+ *   andreas.suter@psi.ch                                                  *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
+ ***************************************************************************/
+
+#ifndef _PVARHANDLER_H_
+#define _PVARHANDLER_H_
+
+#include <string>
+#include <vector>
+
+#include <QString>
+
+#include <PAst.hpp>
+
+class PVarHandler {
+  public:
+    PVarHandler();
+
+    void setInput(QString &str) { fInput = str.toLatin1().data(); }
+    bool parse();
+    bool semcheck();
+    std::vector<double> getValues();
+    std::vector<double> getErrors();
+
+  private:
+    std::string fInput; ///< the variable input to be parsed
+    mupp::ast::statement_list fAst; ///< the AST
+};
+
+#endif //_PVARHANDLER_H_
diff --git a/src/musredit_qt5/mupp/var/src/CMakeLists.txt b/src/musredit_qt5/mupp/var/src/CMakeLists.txt
new file mode 100644
index 00000000..ed93922e
--- /dev/null
+++ b/src/musredit_qt5/mupp/var/src/CMakeLists.txt
@@ -0,0 +1,4 @@
+target_sources(mupp
+  PRIVATE 
+    ${CMAKE_CURRENT_LIST_DIR}/PVarHandler.cpp
+)
diff --git a/src/musredit_qt5/mupp/var/src/PVarHandler.cpp b/src/musredit_qt5/mupp/var/src/PVarHandler.cpp
new file mode 100644
index 00000000..b04b7569
--- /dev/null
+++ b/src/musredit_qt5/mupp/var/src/PVarHandler.cpp
@@ -0,0 +1,83 @@
+/***************************************************************************
+
+  PVarHandler.cpp
+
+  Author: Andreas Suter
+  e-mail: andreas.suter@psi.ch
+
+***************************************************************************/
+
+/***************************************************************************
+ *   Copyright (C) 2007-2020 by Andreas Suter                              *
+ *   andreas.suter@psi.ch                                                  *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
+ ***************************************************************************/
+
+#include "PVarHandler.h"
+
+//--------------------------------------------------------------------------
+/**
+ * @brief PVarHandler::PVarHandler
+ */
+PVarHandler::PVarHandler()
+{
+  fInput = "";
+}
+
+//--------------------------------------------------------------------------
+/**
+ * @brief PVarHandler::parse
+ * @return
+ */
+bool PVarHandler::parse()
+{
+  return true;
+}
+
+//--------------------------------------------------------------------------
+/**
+ * @brief PVarHandler::semcheck
+ * @return
+ */
+bool PVarHandler::semcheck()
+{
+  return true;
+}
+
+//--------------------------------------------------------------------------
+/**
+ * @brief PVarHandler::getValues
+ * @return
+ */
+std::vector<double> PVarHandler::getValues()
+{
+  std::vector<double> result;
+
+  return result;
+}
+
+//--------------------------------------------------------------------------
+/**
+ * @brief PVarHandler::getErrors
+ * @return
+ */
+std::vector<double> PVarHandler::getErrors()
+{
+  std::vector<double> result;
+
+  return result;
+}