[Python-ideas] Fwd: Fwd: unpacking generalisations for list comprehension

[Paul Moore]

On 13 October 2016 at 21:47, אלעזר <elazarg at gmail.com> wrote:
> if you allow result.append(1, 2, 3) to mean result.extend([1,2,3])  # which
> was discussed before

I don't (for the reasons raised before). But thank you for your
explanation, it clarifies what you were proposing. And it does so
within the *current* uses of the * symbol, which is good. But:

1. I'm not keen on extending append's meaning to overlap with extend's
like this.
2. Your proposal does not generalise to generator expressions, set
displays (without similarly modifying the set.add() method) or
dictionary displays.
3. *fn(x) isn't an expression, and yet it *looks* like it should be,
and in the current syntax, an expression is required in that position.
To me, that suggests it would be hard to teach. [1]

You can of course generalise Sjoerd's "from" proposal and then just
replace "from" with "*" throughout. That avoids your requirement to
change append, but at the cost of the translation no longer being a
parallel to an existing use of "*".

Paul

[1] On a purely personal note, I'd say it's confusing, but I don't
want to go back to subjective arguments, so I only note that here as
an opinion, not an argument.