# HG changeset patch
# User Sjoerd Mullender <sjoerd@acm.org>
# Date 1426861570 -3600
# Node ID ff07accd0692e8d4055aa63e7516c41c509c2d8a
# Parent  bd1ca3d502d6e7cec9f12be3a6543e31bb36655f
Don't use print; complain when used as program instead of python hook.

diff -r bd1ca3d502d6 -r ff07accd0692 check_whitespace.py
--- a/check_whitespace.py	Fri Mar 20 14:43:48 2015 +0100
+++ b/check_whitespace.py	Fri Mar 20 15:26:10 2015 +0100
@@ -118,8 +118,7 @@
             # no descendants for this revision, check diff with saved parents
             for p in branches[branch]:
                 for filename, linenum, msg in trailing_whitespace(repo[rev].diff(p)):
-                    print >> sys.stderr, ('%s, line %d: %s added' %
-                                          (filename, linenum, msg))
+                    ui.write('%s, line %d: %s added\n' % (filename, linenum, msg))
                     added = True
     if added:
         # save the commit message so we don't need to retype it
@@ -127,9 +126,13 @@
             cmtsv = os.path.join('.hg','commit.save')
             subprocess.call(['hg', 'tip', '--template', '{desc}'],
                             stdout=open(cmtsv, 'w'))
-            print >> sys.stderr, 'commit message saved to %s' % cmtsv
+            ui.write('commit message saved to %s\n' % cmtsv)
         return 1
 
 if __name__ == '__main__':
-    if hook(None, None, None, None):
-        sys.exit(1)
+    import sys
+    sys.stderr.write('call this hook using the Python interface.\n'
+                     'In your .hgrc file you shoud have:\n'
+                     'pretxncommit.whitespace = python:<path-to-check_whitespace-directory>/check_whitespace.py:hook\n')
+
+    sys.exit(1)