[IronPython] prefix postfix bug

Dino Viehland dinov at exchange.microsoft.com
Thu Jun 8 04:33:16 CEST 2006

Have you tried this in Cpython?  ++ doesn't exist in Python.  So what you're really doing is:

print a + (+(+(+(+b))))

Yep, b sure is positive!

and ++b is the same thing +(+b)

and a++ of course makes no sense, because there's no right hand side to the plus operator.

This might make more sense if you replace b with a number, like 1, where might almost occasionally expect the + operator to be used in front of it, for some reason.

Results from CPython:
>>> a =2 ; b = 6
>>> print a++ + ++b
>>> print ++b
>>> print a++
  File "<stdin>", line 1
    print a++
SyntaxError: invalid syntax
>>> import sys
>>> sys.version
'2.4.2 (#67, Sep 28 2005, 12:41:11) [MSC v.1310 32 bit (Intel)]'
From: users-bounces at lists.ironpython.com On Behalf Of kurtharriger at comcast.net
Sent: Wednesday, June 07, 2006 7:21 PM
To: users at lists.ironpython.com
Subject: [IronPython] prefix postfix bug

a = 2; b=6;
print a++ + ++b  #prints 8
print ++b            #prints 6
print a++           #syntax error (at least when using console)

- Kurt

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