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Re: How to run script from interpreter?

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On Fri, May 30, 2014 at 11:49 AM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> On Fri, 30 May 2014 10:46:34 +1000, Chris Angelico wrote:
>
>> On Fri, May 30, 2014 at 10:33 AM, Steven D'Aprano
>> <steve+comp.lang.python@pearwood.info> wrote:
>>> (By the way, ; won't work for a Python shell, because ;spam already is
>>> valid Python syntax: it's an empty statement followed by the statement
>>> spam, separated by a semicolon.)
>>
>> That's not really a problem, though. It's not going to stop you from
>> doing something actually *useful*, and the fact that the semicolon could
>> be syntactically valid isn't going to come into it, because the REPL
>> would swallow it anyway.
>
> The point is that *syntactically valid* Python statements should not
> behave differently when running inside the shell or not. I thought
> that ;statement was syntactically valid -- but I was wrong. The vanilla
> CPython interactive interpreter gives a syntax error, as do IronPython
> and Jython.

Huh. I responded to your post on the unchecked assumption that ";spam"
was syntactically valid. I'm still of the opinion that technically
valid (but not useful) constructs are allowed to be swallowed by an
interactive interpreter; for instance, it's perfectly valid to write
this:

>>> x = (1
.
imag)

But quite a few interpreters (though not Python) take a dot on its own
line to mean "flush the buffer, cancel my current command". I couldn't
find a way to do this in Python, but if someone proposed adding it,
the fact that the above is syntactically legal shouldn't be a proposal
blocker. It's on par with creating a file with a name beginning with a
hyphen, and then fiddling around with various commands as you try to
manipulate it (tip: "rm ./-r" works); programs will happily interpret
"-r" as an option rather than a file name, without being concerned
that it's technically legal.

ChrisA

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Re: How to run script from interpreter? onlyvinish@gmail.com - 2014-05-28 00:44 -0700
  Re: How to run script from interpreter? Terry Reedy <tjreedy@udel.edu> - 2014-05-28 11:32 -0400
  Re: How to run script from interpreter? Mark H Harris <harrismh777@gmail.com> - 2014-05-28 11:39 -0500
    Re: How to run script from interpreter? Steven D'Aprano <steve@pearwood.info> - 2014-05-29 03:22 +0000
      Re: How to run script from interpreter? Mark H Harris <harrismh777@gmail.com> - 2014-05-29 15:26 -0500
        Re: How to run script from interpreter? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-05-30 00:33 +0000
          Re: How to run script from interpreter? Chris Angelico <rosuav@gmail.com> - 2014-05-30 10:46 +1000
            Re: How to run script from interpreter? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-05-30 01:49 +0000
              Re: How to run script from interpreter? Chris Angelico <rosuav@gmail.com> - 2014-05-30 12:04 +1000
                Re: How to run script from interpreter? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-05-30 06:20 +0000
                Re: How to run script from interpreter? Chris Angelico <rosuav@gmail.com> - 2014-05-30 17:19 +1000
                Re: How to run script from interpreter? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-05-30 11:27 +0000
                Re: How to run script from interpreter? Chris Angelico <rosuav@gmail.com> - 2014-05-30 21:46 +1000
                Re: How to run script from interpreter? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-05-30 19:28 +0000
                Re: How to run script from interpreter? Chris Angelico <rosuav@gmail.com> - 2014-05-31 05:47 +1000
                Re: How to run script from interpreter? Terry Reedy <tjreedy@udel.edu> - 2014-05-30 11:24 -0400

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