On Thu, Apr 16, 2020 at 09:21:05PM -0700, Andrew Barnert via Python-ideas wrote:
> But I don’t see why that rules out the “bare colon” form that I and
> someone else apparently both proposed in separate sub threads of this
> thread:
>
> { :a, "b": x, :c }
>
> as shorthand for:
>
> { "a": a, "b": x, "c": c }
I did a double-take reading that, because I visually parsed it as:
{ :a,
"b":
x, :c
}
and couldn't work out what was going on.
After saving this draft, closing the email, then reopening it, I read
the proposed dict the same way. So I don't think it was just a momentary
glitch.
I think that, as little as I like the original proposal and am not
really convinced it is necessary, I think that it is better to have the
explicit token (the key/parameter name) on the left, and the implicit
token (blank) on the right:
key=
I suspect it may be because we read left-to-right in English and Python,
so having the implicit blank come first is mentally like running into a
pothole at high speed :-)
Perhaps those who read right-to-left languages may have fewer problems
with it. Or maybe it's just me.
> There’s no problem for the parser. Make a trivial change to the
> grammar to add a `":" identifier` alternative to dict display items,
> and nothing becomes ambiguous.
Except to the human reader, which is the only ambiguity that *really*
matter when you get down to it. If human readers are going to parse it
differently from your intention, as I did, then this is going to hurt
readability far in excess of the benefit in saving a few characters
typed.
--
Steven
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