[Python-ideas] Re: New syntax for dict literals
>
> instead of prefixing a letter, we may be able to omit the key of
> items inside dict display.
d = {:name, :addr, ’tel': '123-4567’}
>
This is my favorite variation on the notation so far. I'll give it a +1
On Wed, Jun 10, 2020 at 10:49 AM Atsuo Ishimoto wrote:
> Hi
> Thank you for comments
>
> 2020年6月10日(水) 12:12 Stephen J. Turnbull <
> turnbull.stephen...@u.tsukuba.ac.jp>:
> > DTRTs. How often would locals() be usable in this way? Note: in the
> > case of requests, this might be a vulnerability, because the explicit
> > dict display would presumably include only relevant items, while
> > locals() might inherit private credentials from the arguments, which
> > need to be explicitly del'ed from d.
>
> And in case of locals() is useful, the code may eventually become
> unsafe someday later.
>
> > I understand that this was done for ease of your POC implementatation,
> > and you prefer a letter. But I'd like to emphasize: Please don't use
> > $ for this. Among other things, it is both in appearance and
> > historically based on "S" for "set"!
> >
>
> I don't like it, either. But choice of valid letters are limited to
> such as “$", "'" and "?".
> So I think '$' is the best choice among these letters ;)
>
> > Also, please use dict display syntax (':' not '=').
> >
>
> Ah, this is a typo. I use ':' in my implementation.
>
> > If you're going to use prefix characters, I suggest 'd' for "dict",
> > and maybe 's' for "set" as well (to allow the use case 's{}' for the
> > empty set, though that's not terribly useful vs. set(). I'm mostly
> > proposing it so I be the first to say "-1" on 's{}'. :-)
> >
>
> 'd{}' would be a nice choice.
> >
> > It occurs to me there's an alternative syntax with even less notation:
> >
> > d = {'tel' : '123-456-789', first, last, addr1, addr2}
> >
>
> This is acceptable, but I prefer prefixed dict better.
>
> Or, instead of prefixing a letter, we may be able to omit the key of
> items inside dict display.
>
> d = {:name, :addr, ’tel': '123-4567’}
>
> Thoughts?
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[Python-ideas] Re: New syntax for dict literals
I like Atsou's suggestion of omitting the key for literals:
d = {:name, :addr, ’tel': '123-4567’}
but using empty kwargs feels gross:
d = dict(=name, =addr, tel='123-456')
And this feels like it could easily lead to confusion:
d = dict(name, addr, tell='123-456')
On Thu, Jun 11, 2020 at 4:05 PM Abe Dillon wrote:
> Stephen J. Turnbull
>
>> d = {first : first, last, addr1, addr2}
>
>
> I'm not a huge fan of this solution. It feels a bit like a hack instead of
> an intended syntax. Since prefixing characters on strings is already a
> thing, I lean more towards that solution. It's slightly easier to search
> (e.g. if the notation was d{literal1, literal2, etc}, one might search for
> "python d-dict"). However, If the above notation gains favor, perhaps it
> would be better to allow an empty ':' followed by a comma:
>
> d = {:, first, last, addr1, addr2}
>
> I don't much like the Perlyness of that syntax, but it's similar to using
> a prefix and it might lead to more explicit empty literals like {:} and {,}
> for dict and set respectively. I'm pretty sure that notation for empty
> literals has been discussed and rejected before, so I apologize if this
> brings up well-trodden ground. I'm pretty neutral on the proposal in
> general.
>
> It may also be possible to add a constructor to dict like:
>
> d = dict.from_locals('first', 'last', 'addr1', 'addr2')
> d['tel'] = '123-456-789'
>
> It might require a bit of stack inspection or some other magic, but it
> should be possible. It might be difficult for IDEs to recognize and hint
> and it might also be a blind-spot for re-factoring (if you change the name
> of a local variable).
>
> On Wed, Jun 10, 2020 at 3:06 AM Stephen J. Turnbull <
> turnbull.stephen...@u.tsukuba.ac.jp> wrote:
>
>> Chris Angelico writes:
>> > On Wed, Jun 10, 2020 at 1:15 PM Stephen J. Turnbull
>> > wrote:
>> > >
>> > > Executive summary:
>> > >
>> > > Dicts are unordered, so we can distinguish dict from set by the first
>> > > item (no new notation), and after that default identifiers to (name :
>> > > in-scope value) items.
>> >
>> > Be careful with this assumption. Python's dictionaries DO retain
>> > order,
>>
>> Thank you for the reminder! I did forget that point.
>>
>> > even if you can't easily talk about "the fifth element" [1], so
>> > anything that imposes requirements on the entry listed
>> > syntactically first may have consequences.
>>
>> No requirements imposed! If iteration order matters and you want to
>> take advantage of abbreviation, you might have to write
>>
>> d = {first : first, last, addr1, addr2, tel='123-456-789'}
>>
>> but frequently it would just work naturally:
>>
>> d = {first : first, last, addr1, addr2}
>>
>> Admittedly this distinction may be even more subtle than grit on Tim's
>> screen, or randomizing the hash seed per process. And I suspect that
>> people who want this feature will prefer the d{} notation for
>> consistency inside the braces.
>>
>> Steve
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[Python-ideas] Re: New syntax for dict literals
Stephen J. Turnbull
> d = {first : first, last, addr1, addr2}
I'm not a huge fan of this solution. It feels a bit like a hack instead of
an intended syntax. Since prefixing characters on strings is already a
thing, I lean more towards that solution. It's slightly easier to search
(e.g. if the notation was d{literal1, literal2, etc}, one might search for
"python d-dict"). However, If the above notation gains favor, perhaps it
would be better to allow an empty ':' followed by a comma:
d = {:, first, last, addr1, addr2}
I don't much like the Perlyness of that syntax, but it's similar to using a
prefix and it might lead to more explicit empty literals like {:} and {,}
for dict and set respectively. I'm pretty sure that notation for empty
literals has been discussed and rejected before, so I apologize if this
brings up well-trodden ground. I'm pretty neutral on the proposal in
general.
It may also be possible to add a constructor to dict like:
d = dict.from_locals('first', 'last', 'addr1', 'addr2')
d['tel'] = '123-456-789'
It might require a bit of stack inspection or some other magic, but it
should be possible. It might be difficult for IDEs to recognize and hint
and it might also be a blind-spot for re-factoring (if you change the name
of a local variable).
On Wed, Jun 10, 2020 at 3:06 AM Stephen J. Turnbull <
turnbull.stephen...@u.tsukuba.ac.jp> wrote:
> Chris Angelico writes:
> > On Wed, Jun 10, 2020 at 1:15 PM Stephen J. Turnbull
> > wrote:
> > >
> > > Executive summary:
> > >
> > > Dicts are unordered, so we can distinguish dict from set by the first
> > > item (no new notation), and after that default identifiers to (name :
> > > in-scope value) items.
> >
> > Be careful with this assumption. Python's dictionaries DO retain
> > order,
>
> Thank you for the reminder! I did forget that point.
>
> > even if you can't easily talk about "the fifth element" [1], so
> > anything that imposes requirements on the entry listed
> > syntactically first may have consequences.
>
> No requirements imposed! If iteration order matters and you want to
> take advantage of abbreviation, you might have to write
>
> d = {first : first, last, addr1, addr2, tel='123-456-789'}
>
> but frequently it would just work naturally:
>
> d = {first : first, last, addr1, addr2}
>
> Admittedly this distinction may be even more subtle than grit on Tim's
> screen, or randomizing the hash seed per process. And I suspect that
> people who want this feature will prefer the d{} notation for
> consistency inside the braces.
>
> Steve
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[Python-ideas] Re: New syntax for dict literals
I find this interesting, another solution would be for locals() to take
arguments:
dict(tel='1337-1337', **locals('name', 'surname'))
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[Python-ideas] Re: New syntax for dict literals
Thank you.
It unfortunately happens to me mostly while I'm working for REST web servers,
especially when writing JSON in the test suites for the app.
2020年6月11日(木) 1:24 Rhodri James :
>
> On 10/06/2020 16:38, Atsuo Ishimoto wrote:
> > Hi
> > Thank you for comments
> >
> > 2020年6月10日(水) 0:11 Rhodri James :
> >>
> >> Python is not Perl. By that I mean Python in general tends not to use
> >> non-alphanumeric symbols unless they already have a well established
> >> meaning (such as quote marks, arithmetic operators and so on).
> >
> > Yeah, I don't think '${...}' is appearing, too. As I wrote, it was chosen
> > for
> > implementation reasons. I'm open for other syntax options.
> >
> > I'm curious what you think about another way to construct dictionaries.
>
> Personally I just accept the repetition. It doesn't generally happen
> often to me, and I'd much rather be explicit.
>
> --
> Rhodri James *-* Kynesim Ltd
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[Python-ideas] Re: New syntax for dict literals
On 10/06/2020 16:38, Atsuo Ishimoto wrote:
Hi
Thank you for comments
2020年6月10日(水) 0:11 Rhodri James :
Python is not Perl. By that I mean Python in general tends not to use
non-alphanumeric symbols unless they already have a well established
meaning (such as quote marks, arithmetic operators and so on).
Yeah, I don't think '${...}' is appearing, too. As I wrote, it was chosen for
implementation reasons. I'm open for other syntax options.
I'm curious what you think about another way to construct dictionaries.
Personally I just accept the repetition. It doesn't generally happen
often to me, and I'd much rather be explicit.
--
Rhodri James *-* Kynesim Ltd
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[Python-ideas] Re: New syntax for dict literals
Hi
Thank you for comments
2020年6月10日(水) 12:12 Stephen J. Turnbull :
> DTRTs. How often would locals() be usable in this way? Note: in the
> case of requests, this might be a vulnerability, because the explicit
> dict display would presumably include only relevant items, while
> locals() might inherit private credentials from the arguments, which
> need to be explicitly del'ed from d.
And in case of locals() is useful, the code may eventually become
unsafe someday later.
> I understand that this was done for ease of your POC implementatation,
> and you prefer a letter. But I'd like to emphasize: Please don't use
> $ for this. Among other things, it is both in appearance and
> historically based on "S" for "set"!
>
I don't like it, either. But choice of valid letters are limited to
such as “$", "'" and "?".
So I think '$' is the best choice among these letters ;)
> Also, please use dict display syntax (':' not '=').
>
Ah, this is a typo. I use ':' in my implementation.
> If you're going to use prefix characters, I suggest 'd' for "dict",
> and maybe 's' for "set" as well (to allow the use case 's{}' for the
> empty set, though that's not terribly useful vs. set(). I'm mostly
> proposing it so I be the first to say "-1" on 's{}'. :-)
>
'd{}' would be a nice choice.
>
> It occurs to me there's an alternative syntax with even less notation:
>
> d = {'tel' : '123-456-789', first, last, addr1, addr2}
>
This is acceptable, but I prefer prefixed dict better.
Or, instead of prefixing a letter, we may be able to omit the key of
items inside dict display.
d = {:name, :addr, ’tel': '123-4567’}
Thoughts?
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[Python-ideas] Re: New syntax for dict literals
Hi
Thank you for comments
2020年6月10日(水) 0:11 Rhodri James :
>
> Python is not Perl. By that I mean Python in general tends not to use
> non-alphanumeric symbols unless they already have a well established
> meaning (such as quote marks, arithmetic operators and so on).
Yeah, I don't think '${...}' is appearing, too. As I wrote, it was chosen for
implementation reasons. I'm open for other syntax options.
I'm curious what you think about another way to construct dictionaries.
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[Python-ideas] Re: New syntax for dict literals
Chris Angelico writes:
> On Wed, Jun 10, 2020 at 1:15 PM Stephen J. Turnbull
> wrote:
> >
> > Executive summary:
> >
> > Dicts are unordered, so we can distinguish dict from set by the first
> > item (no new notation), and after that default identifiers to (name :
> > in-scope value) items.
>
> Be careful with this assumption. Python's dictionaries DO retain
> order,
Thank you for the reminder! I did forget that point.
> even if you can't easily talk about "the fifth element" [1], so
> anything that imposes requirements on the entry listed
> syntactically first may have consequences.
No requirements imposed! If iteration order matters and you want to
take advantage of abbreviation, you might have to write
d = {first : first, last, addr1, addr2, tel='123-456-789'}
but frequently it would just work naturally:
d = {first : first, last, addr1, addr2}
Admittedly this distinction may be even more subtle than grit on Tim's
screen, or randomizing the hash seed per process. And I suspect that
people who want this feature will prefer the d{} notation for
consistency inside the braces.
Steve
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[Python-ideas] Re: New syntax for dict literals
On Wed, Jun 10, 2020 at 1:15 PM Stephen J. Turnbull wrote: > > Executive summary: > > Dicts are unordered, so we can distinguish dict from set by the first > item (no new notation), and after that default identifiers to (name : > in-scope value) items. Also some notational bikeshedding. Be careful with this assumption. Python's dictionaries DO retain order, even if you can't easily talk about "the fifth element" [1], so anything that imposes requirements on the entry listed syntactically first may have consequences. ChrisA [1] which, as we all know, is Boron ___ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/EMT5JC5K6JCME5U6HKOWD3XBTHZEBFSD/ Code of Conduct: http://python.org/psf/codeofconduct/
[Python-ideas] Re: New syntax for dict literals
Hi there!
This request is a close cousin of the recent discussion about optional
keywords arguments, which you can find in the archives at
https://mail.python.org/archives/list/python-ideas@python.org/thread/MILIX6HSW3PRUNWWP6BN2G2D7PXYFZJ7/
A lot of the same comments for and against apply here. I'll just
cherry-pick a specific point:
On 09/06/2020 14:45, Atsuo Ishimoto wrote:
How about adding similar syntax to Python? Like raw strings, we can
add prefix letters such as '$' to the opening curly brace for the
purpose.
d = ${first, last, addr1, addr2, tel='123-456-789'}
Python is not Perl. By that I mean Python in general tends not to use
non-alphanumeric symbols unless they already have a well established
meaning (such as quote marks, arithmetic operators and so on). "${...}"
definitely does not have such a meaning; a newcomer looking at the above
would not have a lot of guidance as to what might be going on, and could
be forgiven for thinking they were looking at some weird form of set.
--
Rhodri James *-* Kynesim Ltd
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