Hi William,
On Thu, Apr 15, 2010 at 10:02 PM, William Stein <wst...@gmail.com> wrote:
<SNIP>
> That is another issue. It doesn't cause any trouble in python, so it
> doesn't concern me.
I have an Emacs keyboard shortcut that removes all trailing white
spaces in a file. When I started out with Python programming, I wrote
a statement that spans more than 80 characters wide. To break that
statement up into a multiline statement, I used the backslash
character. When I ran the file through Python and Sage, an error came
out reporting about unexpected characters. Some digging revealed that
I had trailing white spaces after the backslash. To illustrate what I
mean, consider the following conditional:
[mv...@sage ~]$ cat demo.sage
if 3 > 2 and \
2 == 2:
print True
[mv...@sage ~]$ sage demo.sage
File "demo.py", line 4
if _sage_const_3 > _sage_const_2 and \
^
SyntaxError: unexpected character after line continuation character
Note that there is a trailing white space after the line "3 > 2 and
\". PEP008 [1] recommends using parentheses for multiline statements.
So the above conditional could be written as:
[mv...@sage ~]$ cat demo.sage
if (3 > 2 and
2 == 2):
print True
[mv...@sage ~]$ sage demo.sage
True
Parentheses have implicit continuation, so it doesn't matter if you
have trailing white spaces after "if (3 > 2 and".
[1] http://www.python.org/dev/peps/pep-0008/
--
Regards
Minh Van Nguyen
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