[ python-Bugs-1543347 ] Operator precedence inconsistent for complex literal

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Sun Aug 20 07:59:55 CEST 2006


Bugs item #1543347, was opened at 2006-08-20 14:59
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Category: Python Interpreter Core
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: [N/A] (ymasuda)
Assigned to: Nobody/Anonymous (nobody)
Summary: Operator precedence inconsistent for complex literal

Initial Comment:
Using complex, real and imag attributes are computed collectly as
follows:

>>> 1+2j
(1+2j)
>>> z = 1+2j
>>> z.real
1.0
>>> z.imag
2.0
>>> (1+2j).real
1.0  
>>> (1+2j).imag
2.0

But, if there's no explicit literal boundary, it seems to break
consistensy in operator precedence:

>>> 1+2j.real            # addition succeeds j-suffux
1.0
>>> 1+2j.imag          # addition precedes (j-suffix and) attribute 
reference 
3.0
>>> 0+1+2j.real       # same as above
1.0
>>> 0+1+2j.imag
3.0
>>> 1+0+2j.imag
3.0
>>> 1+0+2j.real
1.0
>>> 1+(2j).imag        # brace puts no bless
3.0
>>> 1*1+2j.imag      # star fails to steer
3.0

This happens at least on Python 2.3.5 (OSX bundled), Python 2.4.2 
(build from ports, FreeBSD 5.4).

# Practically, of course, you always explicit (1+2j) to construct complex
thus hardly troubled with this :) but it would be happy for beginners to 
mention it on standard tutorial or something.

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