diff --git a/preprocessor.py b/preprocessor.py
index 92aac14..580b067 100644
--- a/preprocessor.py
+++ b/preprocessor.py
@@ -21,13 +21,13 @@ def parseFunctionText(s):
 def parseFunction(s, linenumber):
     parsed = re.search(functionRegex, s)
     name, args, text =  parsed.group(1), parsed.group(2).split(","), parsed.group(3)
-    if verbose: print '<parser:' + str(linenumber) + '> parsed function ' + name + ' -> ' + str(args)
+    if verbose: print('<parser:' + str(linenumber) + '> parsed function ' + name + ' -> ' + str(args))
     functions[name] = args, parseFunctionText(text)
 
 def parseDefinition(s, linenumber):
     parsed = re.search(definitionRegex, s)
     name, value = parsed.group(1), parsed.group(2)
-    if verbose: print '<parser:' + str(linenumber) + '> parsed definition ' + name + ' -> ' + value
+    if verbose: print('<parser:' + str(linenumber) + '> parsed definition ' + name + ' -> ' + value)
     definitions[name] = value
 
 def parseFunctionCall(s):
@@ -57,13 +57,12 @@ def transformFile(inputFilename):
 
 def preprocessLine(s, linenumber):
     # if, else, endif block
-    global preprocessorState
-    global verbose
+    global preprocessorState, verbose
     modified = preprocessorState
     if re.match(ifDefRegex, s) != None or re.match(ifNDefRegex, s) != None:
         invert = re.match(ifNDefRegex, s) != None
         if preprocessorState != 'initial':
-            print str(linenumber) + ': nested #ifdef/#ifndef is not supported!'
+            print (str(linenumber) + ': nested #ifdef/#ifndef is not supported!')
             sys.exit(-1)
         keyword = re.search((ifNDefRegex if invert else ifDefRegex), s).group(1)
         if keyword in definitions:
@@ -76,17 +75,17 @@ def preprocessLine(s, linenumber):
         elif preprocessorState == 'ifdef_true':
             preprocessorState = 'else_false'            
         else:
-            print str(linenumber) + ': invalid #else statement'
+            print(str(linenumber) + ': invalid #else statement')
             sys.exit(-1)
         return None
     elif re.match(endifDefRegex, s) != None:
         if preprocessorState == 'initial':
-            print 'invalid #endif statement at line ' + str(linenumber)
+            print('invalid #endif statement at line ' + str(linenumber))
             sys.exit(-1)
         preprocessorState = 'initial'
 
     if preprocessorState != modified:
-        if verbose: print '<pre:' + str(linenumber) + '> ' + preprocessorState + ': \t' + s.rstrip()
+        if verbose: print('<pre:' + str(linenumber) + '> ' + preprocessorState + ': \t' + s.rstrip())
         return None
 
     if re.match(includeRegex, s) != None:
@@ -99,7 +98,7 @@ def preprocessLine(s, linenumber):
         return None
         
     # definition expansion
-    for name, value in definitions.items():
+    for name, value in list(definitions.items()):
         if name in s:
             s = s.replace(name, value)
 
@@ -107,10 +106,10 @@ def preprocessLine(s, linenumber):
     if isFunctionCall(s):
         linename, lineargs = parseFunctionCall(s)
         if linename in functions:
-            if verbose: print '<pre:' + str(linenumber) + '> matched ' + linename + str(lineargs)
+            if verbose: print('<pre:' + str(linenumber) + '> matched ' + linename + str(lineargs))
             args, text = functions[linename]
             if len(args) != len(lineargs):
-                print 'error: call to ' + linename + ' needs ' + str(len(args)) + ' arguments'
+                print('error: call to ' + linename + ' needs ' + str(len(args)) + ' arguments')
                 sys.exit(-1)
             for i, a in enumerate(args):
                 text = text.replace(a, lineargs[i])
diff --git a/test.py b/test.py
index ff73fab..a07c142 100755
--- a/test.py
+++ b/test.py
@@ -16,18 +16,18 @@ def checkFile(A, B):
     
 files = [x for x in os.listdir(subdirectory) if not x.endswith(expectedSuffix)]
 if len(files) == 0:
-    print 'no tests found'
+    print('no tests found')
     
 for i, filename in enumerate(files):
     pair = (subdirectory + filename, subdirectory + filename + outputSuffix)
     preprocessor.preprocessFile(*pair)
     checkPair = (subdirectory + filename + outputSuffix, subdirectory + filename + expectedSuffix)
     if checkFile(*checkPair) != True:
-        print 'check failed for ' + str(checkPair)
+        print(('check failed for ' + str(checkPair)))
         sys.exit(-1)
-    print 'checked ' + str(i + 1) + ' of ' + str(len(files)) + ': ' + str(pair[0])
+    print(('checked ' + str(i + 1) + ' of ' + str(len(files)) + ': ' + str(pair[0])))
 
-print 'all checks ok'
+print('all checks ok')
 
 for p in [x for x in os.listdir(subdirectory) if x.endswith('.p')]:
     os.remove(subdirectory + p)
diff --git a/tpypp.py b/tpypp.py
index 06e70d2..5da7304 100755
--- a/tpypp.py
+++ b/tpypp.py
@@ -23,10 +23,10 @@
 pass_verbose = False
 
 if not 2 <= len(sys.argv) <= 4:
-    print helpstring
+    print(helpstring)
     sys.exit(-1)
 if len(sys.argv) == 3 and sys.argv[1] == sys.argv[2]:
-    print 'input file cannot be same as output file'
+    print('input file cannot be same as output file')
     sys.exit(-1)
 if (len(sys.argv) == 3 and sys.argv[2] == '--v') or (len(sys.argv) == 4 and sys.argv[3] == '--v'):
     pass_verbose = True