diff --git a/src/backend/gsl/parser.h b/src/backend/gsl/parser.h
index af9285ebb..68a7e11db 100644
--- a/src/backend/gsl/parser.h
+++ b/src/backend/gsl/parser.h
@@ -1,86 +1,87 @@
 /***************************************************************************
     File                 : parser.h
     Project              : LabPlot
     Description          : Parser for mathematical expressions
     --------------------------------------------------------------------
-    Copyright            : (C) 2014 Stefan Gerlach  (stefan.gerlach@uni-konstanz.de)
+    Copyright            : (C) 2014-2017 Stefan Gerlach  (stefan.gerlach@uni.kn)
     Copyright            : (C) 2014 Alexander Semke (alexander.semke@web.de)
 
  ***************************************************************************/
 
 /***************************************************************************
  *                                                                         *
  *  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., 51 Franklin Street, Fifth Floor,                    *
  *   Boston, MA  02110-1301  USA                                           *
  *                                                                         *
  ***************************************************************************/
 
 #ifndef PARSER_H
 #define PARSER_H
 
+/* uncomment to enable parser specific debugging */
 /* #define PDEBUG 1 */
 
 struct con {
 	char const *name;
 	double value;
 };
 
 struct func {
 	char const *name;
 #ifdef _MSC_VER
 	double (*fnct)(void);
 #else
 	double (*fnct)();
 #endif
 };
 
 /* variables to pass to parser */
 #define MAX_VARNAME_LENGTH 10
 typedef struct parser_var {
 	char name[MAX_VARNAME_LENGTH];
 	double value;
 } parser_var;
 
 /* Functions type */
 #ifdef _MSC_VER
 typedef double (*func_t) (void);
 #else
 typedef double (*func_t) ();
 #endif
 
 /* structure for list of symbols */
 typedef struct symrec {
 	char *name;	/* name of symbol */
 	int type;	/* type of symbol: either VAR or FNCT */
 	union {
 		double var;	/* value of a VAR */
 		func_t fnctptr;	/* value of a FNCT */
 	} value;
 	struct symrec *next;	/* next field */
 } symrec;
 
 void init_table(void);	/* initialize symbol table */
 void delete_table(void);	/* delete symbol table */
 int parse_errors(void);
 symrec* assign_variable(const char* symb_name, double value);
 /*new style: symrec* assign_variable(symrec *sym_table, parser_var var);*/
 double parse(const char *str);
 double parse_with_vars(const char[], const parser_var[], int nvars);
 
 extern struct con _constants[];
 extern struct func _functions[];
 
 
 #endif /*PARSER_H*/