[Tutor] Potential problem with Game Over 2.0 problem in "Python Programming for the Absolute Beginner, 3rd Ed."

[boB Stepp]

On Tue, Feb 17, 2015 at 12:43 PM, Danny Yoo <dyoo at hashcollision.org> wrote:

[...]

> Ah ha.  Escape characters.  I see what you mean.  :P
>
>
> Just to add: there is a "raw" string literal syntax that will turn off
> escape sequence handling.  Using a raw string literal may make it
> easier to type the value in question.
>
> We can use raw literal strings by prepending a 'r' in the front of the
> string literal.  e.g.:
>
> ##########################################
>>>> x = r'''
> ... this\
> ... is\
> ... a/
> ... test\
> ... '''
>>>> x
> '\nthis\\\nis\\\na/\ntest\\\n'
>>>> print x
>
> this\
> is\
> a/
> test\
> ##########################################

Actually, that is the solution I recommended to my son to use.

> It might be that the question is trying to motivate the use of raw
> string literals, or teaching about escape sequences.  I don't have the
> book, so I can't say for sure.

At this point in the text he is not talking about raw literal strings.
I examined the author's source and he has obviously inserted at least
one space between each use of a backslash at the end of a line and the
EOL terminating characters. He did not do this with the "Game" portion
of the code, which did not make any use of "\" . When the file is run
everything behaves as desired. But if, as my son did, you leave no
spaces between the last backslash and the EOL termination characters,
then the problem behavior occurs. Actually, I realize I have a
question:

If I do the following in the Win7 command line Python interpreter:

Python 3.4.2 (v3.4.2:ab2c023a9432, Oct  6 2014, 22:16:31) [MSC v.1600 64 bit (AM
D64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> print("""
... boB\
... Stepp
... """
... )

boB\
Stepp

Here I placed exactly one space between "\" and where I pressed
"Enter". This would be the Game Over 2.0 desired behavior. However, if
I bring up the IDLE Python interpreter and do the exact same thing:

Python 3.4.2 (v3.4.2:ab2c023a9432, Oct  6 2014, 22:16:31) [MSC v.1600
64 bit (AMD64)] on win32
Type "copyright", "credits" or "license()" for more information.
>>> print("""
boB\
Stepp
"""
      )

boBStepp

it gives the undesired behavior. I typed exactly the same character
sequences, though IDLE displayed things slightly differently, e.g.,
the command line interpreter put in "..." in several places, where the
IDLE interpreter did not. I am currently scratching my head on these
differences, and am currently guessing that IDLE implements the Python
interpreter somewhat differently than the implementation that occurs
in the Windows command line. Do you have an explanation for these
differences?

-- 
boB