On Fri, May 30, 2014 at 11:49 AM, Steven D'Aprano <steve+comp.lang.pyt...@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.pyt...@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 -- https://mail.python.org/mailman/listinfo/python-list
