qapi: convert to use python print function instead of statement

Python 3 no longer supports the bare "print" statement, it must be
called as a normal function with round brackets. It is possible to
opt-in to this new syntax with Python 2.6 onwards by importing the
"print_function" from the "__future__" module, making it easy to
support Python 2 and 3 in parallel.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <20180116134217.8725-2-berrange@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

scripts/qapi.py

@@ -11,6 +11,7 @@
 # This work is licensed under the terms of the GNU GPL, version 2.
 # See the COPYING file in the top-level directory.
 
+from __future__ import print_function
 import errno
 import getopt
 import os
@@ -1467,7 +1468,7 @@ def __init__(self, fname):
             self._def_exprs()
             self.check()
         except QAPIError as err:
-            print >>sys.stderr, err
+            print(err, file=sys.stderr)
             exit(1)
 
     def _def_entity(self, ent):
@@ -1931,7 +1932,7 @@ def parse_command_line(extra_options='', extra_long_options=[]):
                                        ['source', 'header', 'prefix=',
                                         'output-dir='] + extra_long_options)
     except getopt.GetoptError as err:
-        print >>sys.stderr, "%s: %s" % (sys.argv[0], str(err))
+        print("%s: %s" % (sys.argv[0], str(err)), file=sys.stderr)
         sys.exit(1)
 
     output_dir = ''
@@ -1945,9 +1946,8 @@ def parse_command_line(extra_options='', extra_long_options=[]):
         if o in ('-p', '--prefix'):
             match = re.match(r'([A-Za-z_.-][A-Za-z0-9_.-]*)?', a)
             if match.end() != len(a):
-                print >>sys.stderr, \
-                    "%s: 'funny character '%s' in argument of --prefix" \
-                    % (sys.argv[0], a[match.end()])
+                print("%s: 'funny character '%s' in argument of --prefix" \
+                      % (sys.argv[0], a[match.end()]), file=sys.stderr)
                 sys.exit(1)
             prefix = a
         elif o in ('-o', '--output-dir'):
@@ -1964,7 +1964,7 @@ def parse_command_line(extra_options='', extra_long_options=[]):
         do_h = True
 
     if len(args) != 1:
-        print >>sys.stderr, "%s: need exactly one argument" % sys.argv[0]
+        print("%s: need exactly one argument" % sys.argv[0], file=sys.stderr)
         sys.exit(1)
     fname = args[0]
 

scripts/qapi2texi.py

@@ -4,6 +4,7 @@
 # This work is licensed under the terms of the GNU LGPL, version 2+.
 # See the COPYING file in the top-level directory.
 """This script produces the documentation of a qapi schema in texinfo format"""
+from __future__ import print_function
 import re
 import sys
 
@@ -274,15 +275,15 @@ def texi_schema(schema):
 def main(argv):
     """Takes schema argument, prints result to stdout"""
     if len(argv) != 2:
-        print >>sys.stderr, "%s: need exactly 1 argument: SCHEMA" % argv[0]
+        print("%s: need exactly 1 argument: SCHEMA" % argv[0], file=sys.stderr)
         sys.exit(1)
 
     schema = qapi.QAPISchema(argv[1])
     if not qapi.doc_required:
-        print >>sys.stderr, ("%s: need pragma 'doc-required' "
-                             "to generate documentation" % argv[0])
+        print("%s: need pragma 'doc-required' "
+               "to generate documentation" % argv[0], file=sys.stderr)
         sys.exit(1)
-    print texi_schema(schema)
+    print(texi_schema(schema))
 
 
 if __name__ == '__main__':

tests/qapi-schema/test-qapi.py

@@ -10,6 +10,7 @@
 # See the COPYING file in the top-level directory.
 #
 
+from __future__ import print_function
 from qapi import *
 from pprint import pprint
 import os
@@ -18,51 +19,51 @@
 
 class QAPISchemaTestVisitor(QAPISchemaVisitor):
     def visit_enum_type(self, name, info, values, prefix):
-        print 'enum %s %s' % (name, values)
+        print('enum %s %s' % (name, values))
         if prefix:
-            print '    prefix %s' % prefix
+            print('    prefix %s' % prefix)
 
     def visit_object_type(self, name, info, base, members, variants):
-        print 'object %s' % name
+        print('object %s' % name)
         if base:
-            print '    base %s' % base.name
+            print('    base %s' % base.name)
         for m in members:
-            print '    member %s: %s optional=%s' % \
-                (m.name, m.type.name, m.optional)
+            print('    member %s: %s optional=%s' % \
+                  (m.name, m.type.name, m.optional))
         self._print_variants(variants)
 
     def visit_alternate_type(self, name, info, variants):
-        print 'alternate %s' % name
+        print('alternate %s' % name)
         self._print_variants(variants)
 
     def visit_command(self, name, info, arg_type, ret_type,
                       gen, success_response, boxed):
-        print 'command %s %s -> %s' % \
-            (name, arg_type and arg_type.name, ret_type and ret_type.name)
-        print '   gen=%s success_response=%s boxed=%s' % \
-            (gen, success_response, boxed)
+        print('command %s %s -> %s' % \
+              (name, arg_type and arg_type.name, ret_type and ret_type.name))
+        print('   gen=%s success_response=%s boxed=%s' % \
+              (gen, success_response, boxed))
 
     def visit_event(self, name, info, arg_type, boxed):
-        print 'event %s %s' % (name, arg_type and arg_type.name)
-        print '   boxed=%s' % boxed
+        print('event %s %s' % (name, arg_type and arg_type.name))
+        print('   boxed=%s' % boxed)
 
     @staticmethod
     def _print_variants(variants):
         if variants:
-            print '    tag %s' % variants.tag_member.name
+            print('    tag %s' % variants.tag_member.name)
             for v in variants.variants:
-                print '    case %s: %s' % (v.name, v.type.name)
+                print('    case %s: %s' % (v.name, v.type.name))
 
 schema = QAPISchema(sys.argv[1])
 schema.visit(QAPISchemaTestVisitor())
 
 for doc in schema.docs:
     if doc.symbol:
-        print 'doc symbol=%s' % doc.symbol
+        print('doc symbol=%s' % doc.symbol)
     else:
-        print 'doc freeform'
-    print '    body=\n%s' % doc.body.text
+        print('doc freeform')
+    print('    body=\n%s' % doc.body.text)
     for arg, section in doc.args.iteritems():
-        print '    arg=%s\n%s' % (arg, section.text)
+        print('    arg=%s\n%s' % (arg, section.text))
     for section in doc.sections:
-        print '    section=%s\n%s' % (section.name, section.text)
+        print('    section=%s\n%s' % (section.name, section.text))