[Tutor] Syntax error while attempting to type in multiline statements in the interactive interpreter

[boB Stepp]

I'm beginning to believe I am being incredibly dense today ...

On Sat, Feb 4, 2017 at 6:16 PM, Ben Finney <ben+python at benfinney.id.au> wrote:
> boB Stepp <robertvstepp at gmail.com> writes:
>
>> But would it not be more consistent to assume the user knows what he
>> is doing based on the new (lack of) indentation being used, accept
>> that a new section of code outside of the for loop is being typed in,
>> and wait for the blank line before executing everything typed in?
>
> That's not the purpose of the REPL. It is to Read (one statement),
> Evaluate the statement, Print the result, and Loop.
>
> You're wanting a different behaviour: wait until all the input has been
> read, then evaluate it all.

Ben, I read your answer, did some Googling on REPL, seemed satisfied,
and consigned this thread of emails to the trash bin, believing it was
all settled in my mind.  But then I got to wondering again ...

As already mentioned the interactive interpreter handles multiline
statements.  In the case of defining a function, the interpreter
allows quite complex, nested code to be entered, only ending the input
of code process when that blank line occurs in proper context.  By
this I mean that quotes have been properly closed, all parens matched,
etc.

But it seems to me on further thought that both REPL and what seems
most consistent to me, "...wait until all the input has been read,
then evaluate it all..." amounts to the same thing in the case of
entering function definitions into the interpreter.  The interpreter
cannot know that the user has finished inputting code until it
encounters that finalizing blank line.  After all I can have in my
function many for loops followed by unindented print functions in
seeming as much complexity as I can bear to type in accurately.  This
is giving exactly the consistent behavior that I would expect.  But if
instead of starting with a for loop inside a function with following
unindented other statements I instead start with *exactly the same
sequence of statements* but without "def ...:", then I get a syntax
error.  I am not trying to be deliberately argumentative, but I do not
see why the two cases are treated differently when the entered code is
exactly the same between the two with the sole exception of one has an
enclosing function definition line the other code does not.  I am
continuing to scratch my evermore balding head on this one!  But it is
not a big deal, and I do not want to blow things out of proportion.

More practically, I wonder if it is all as simple as not having to hit
the enter key twice for true one-liner statements.  Such lines can
truly be handled one line at a time per REPL.  If I had things "my
way", then that would make the more common situation of true
one-line-at-a-time read-evaluate-print-loop more cumbersome.

-- 
boB