[Python-ideas] Is there any idea about dictionary destructing?

[Brett Cannon]

On Mon, 9 Apr 2018 at 05:18 Joao S. O. Bueno <jsbueno at python.org.br> wrote:

> I have an idea for an inovative, unanbiguous, straightforward and
> backwards compatible syntax for that,
> that evena llows one to pass metadata along the operation so that the
> results can be tweaked acording
> to each case's needs.
>
> What about:
>
> new_data = dict_feed({
>         "direct": "some data",
>         "nested": {
>             "lst_data": [1, 2, 3],
>             "int_data": 1
>         }
>     },
> data
> )
>
> we could even call this approach a name such as "function call".
>

The harsh sarcasm is not really called for.

-Brett


>
>
> In other words, why to bloat the language with hard to learn, error prone,
> grit-looking syntax, when a simple plain function call is perfectly
> good, all you need to do over
> your suggestion is to type the function name and a pair of parentheses?
>
>
>
>
> On 7 April 2018 at 14:26, thautwarm <yaoxiansamma at gmail.com> wrote:
> > We know that Python support the destructing of iterable objects.
> >
> > m_iter = (_ for _ in range(10))
> > a, *b, c = m_iter
> >
> > That's pretty cool! It's really convenient when there're many corner
> cases
> > to handle with iterable collections.
> > However destructing in Python could be more convenient if we support
> > dictionary destructing.
> >
> > In my opinion, dictionary destructing is not difficult to implement and
> > makes the syntax more expressive. A typical example is data access on
> nested
> > data structures(just like JSON), destructing a dictionary makes the logic
> > quite clear:
> >
> > data = {
> >     "direct": "some data",
> >     "nested": {
> >         "lst_data": [1, 2, 3],
> >         "int_data": 1
> >     }
> > }
> > {
> >    "direct": direct,
> >     "nested": {
> >         "lst_data": [a, b, c],
> >     }
> > } = data
> >
> >
> > Dictionary destructing might not be very well-known but it really helps.
> The
> > operations on nested key-value collections are very frequent, and the
> codes
> > for business logic are not readable enough until now. Moreover Python is
> now
> > popular in data processing which must be enhanced by the entire support
> of
> > data destructing.
> >
> > Here are some implementations of other languages:
> > Elixir, which is also a popular dynamic language nowadays.
> >
> > iex> %{} = %{:a => 1, 2 => :b}
> > %{2 => :b, :a => 1}
> > iex> %{:a => a} = %{:a => 1, 2 => :b}
> > %{2 => :b, :a => 1}
> > iex> a
> > 1
> > iex> %{:c => c} = %{:a => 1, 2 => :b}
> > ** (MatchError) no match of right hand side value: %{2 => :b, :a => 1}
> >
> > And in F#, there is something similar to dictionary destructing(actually,
> > this destructs `struct` instead)
> > type MyRecord = { Name: string; ID: int } let IsMatchByName record1
> (name:
> > string) = match record1 with | { MyRecord.Name = nameFound; MyRecord.ID
> = _;
> > } when nameFound = name -> true | _ -> false let recordX = { Name =
> > "Parker"; ID = 10 } let isMatched1 = IsMatchByName recordX "Parker" let
> > isMatched2 = IsMatchByName recordX "Hartono"
> >
> > All of them partially destructs(or matches) a dictionary.
> >
> > thautwarm
> >
> >
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