Re: [swift-evolution] Add transformers to Codable

[Tony Parker via swift-evolution]

Hi Arsen,

What’s the difference between providing a method that takes a transformable 
object on the keyed container protocol and just transforming it yourself before 
you encode it?

- Tony

> On Dec 18, 2017, at 8:51 AM, Arsen Gasparyan via swift-evolution 
>  wrote:
> 
> Hello everyone,
> 
> I’m suggesting to add a new way to encode/decode JSON properties for 
> relevantly complex data formats such as regular expressions, well-known text, 
> hex colours, custom date formats.
> 
> The problem:
> 
> Image you have a struct called House
> 
> struct House {
> let color: UIColor
> }
> 
> and it has a properly called color and the color represented in JSON as hex 
> value (#ff). Currently to make it working you have to extract the 
> underline value (string with a hex value) and then try to make a UIColor from 
> it. It works but it makes you to copy/past a lot of code and it leads to 
> problems. Also it shifts focus from what to decode to how to decode.
> 
> The suggested solution:
> 
> I suggest that we have to introduce protocols for classes that will 
> encapsulate transformation from a source data type to a destination data 
> type. The source data types are all existing data that support of decoding. 
> 
> We will provide only protocols (one for decoding and one for encoding) and 
> users will be able to create transformers for their own data types.
> 
> The implementation:
> 
> The implementation is fairly easy. We only need introduce two protocols 
> (encoding/decoding) and add a method to KeyedEncodingContainerProtocol that 
> will accept a key and a transformer. In the method we will extract source 
> data from JSON and then will ask the transformer to try to convert it to the 
> desire data type.
> 
> Example of the decoding protocol:
> 
> protocol DecodingTransformer {
> associatedtype Input: Decodable
> associatedtype Output
> func transform(_ decoded: Input) throws -> Output
> }
> 
> 
> Inspired by: https://github.com/Hearst-DD/ObjectMapper#custom-transforms 
> 
> 
> Cheers,
> Arsen
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Re: [swift-evolution] Add transformers to Codable

[Goffredo Marocchi via swift-evolution]

+1 this is missing functionality at the moment and what still puts tools like 
Mantle ahead.

Sent from my iPhone

> On 19 Dec 2017, at 04:18, Charlie Monroe via swift-evolution 
>  wrote:
> 
> For me definitely +1 as it's getting near to what I need to call the Decoding 
> usable.
> 
>> On Dec 18, 2017, at 5:51 PM, Arsen Gasparyan via swift-evolution 
>>  wrote:
>> 
>> Hello everyone,
>> 
>> I’m suggesting to add a new way to encode/decode JSON properties for 
>> relevantly complex data formats such as regular expressions, well-known 
>> text, hex colours, custom date formats.
>> 
>> The problem:
>> 
>> Image you have a struct called House
>> 
>> struct House {
>> let color: UIColor
>> }
>> 
>> and it has a properly called color and the color represented in JSON as hex 
>> value (#ff). Currently to make it working you have to extract the 
>> underline value (string with a hex value) and then try to make a UIColor 
>> from it. It works but it makes you to copy/past a lot of code and it leads 
>> to problems. Also it shifts focus from what to decode to how to decode.
>> 
>> The suggested solution:
>> 
>> I suggest that we have to introduce protocols for classes that will 
>> encapsulate transformation from a source data type to a destination data 
>> type. The source data types are all existing data that support of decoding. 
>> 
>> We will provide only protocols (one for decoding and one for encoding) and 
>> users will be able to create transformers for their own data types.
>> 
>> The implementation:
>> 
>> The implementation is fairly easy. We only need introduce two protocols 
>> (encoding/decoding) and add a method to KeyedEncodingContainerProtocol that 
>> will accept a key and a transformer. In the method we will extract source 
>> data from JSON and then will ask the transformer to try to convert it to the 
>> desire data type.
>> 
>> Example of the decoding protocol:
>> 
>> protocol DecodingTransformer {
>> associatedtype Input: Decodable
>> associatedtype Output
>> func transform(_ decoded: Input) throws -> Output
>> }
>> 
>> 
>> Inspired by: https://github.com/Hearst-DD/ObjectMapper#custom-transforms
>> 
>> Cheers,
>> Arsen
>> ___
>> swift-evolution mailing list
>> swift-evolution@swift.org
>> https://lists.swift.org/mailman/listinfo/swift-evolution
> 
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Re: [swift-evolution] Add transformers to Codable

[Charlie Monroe via swift-evolution]

For me definitely +1 as it's getting near to what I need to call the Decoding 
usable.

> On Dec 18, 2017, at 5:51 PM, Arsen Gasparyan via swift-evolution 
>  wrote:
> 
> Hello everyone,
> 
> I’m suggesting to add a new way to encode/decode JSON properties for 
> relevantly complex data formats such as regular expressions, well-known text, 
> hex colours, custom date formats.
> 
> The problem:
> 
> Image you have a struct called House
> 
> struct House {
> let color: UIColor
> }
> 
> and it has a properly called color and the color represented in JSON as hex 
> value (#ff). Currently to make it working you have to extract the 
> underline value (string with a hex value) and then try to make a UIColor from 
> it. It works but it makes you to copy/past a lot of code and it leads to 
> problems. Also it shifts focus from what to decode to how to decode.
> 
> The suggested solution:
> 
> I suggest that we have to introduce protocols for classes that will 
> encapsulate transformation from a source data type to a destination data 
> type. The source data types are all existing data that support of decoding. 
> 
> We will provide only protocols (one for decoding and one for encoding) and 
> users will be able to create transformers for their own data types.
> 
> The implementation:
> 
> The implementation is fairly easy. We only need introduce two protocols 
> (encoding/decoding) and add a method to KeyedEncodingContainerProtocol that 
> will accept a key and a transformer. In the method we will extract source 
> data from JSON and then will ask the transformer to try to convert it to the 
> desire data type.
> 
> Example of the decoding protocol:
> 
> protocol DecodingTransformer {
> associatedtype Input: Decodable
> associatedtype Output
> func transform(_ decoded: Input) throws -> Output
> }
> 
> 
> Inspired by: https://github.com/Hearst-DD/ObjectMapper#custom-transforms 
> 
> 
> Cheers,
> Arsen
> ___
> swift-evolution mailing list
> swift-evolution@swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution

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[swift-evolution] Add transformers to Codable

[Arsen Gasparyan via swift-evolution]

Hello everyone,

I’m suggesting to add a new way to encode/decode JSON properties for relevantly 
complex data formats such as regular expressions, well-known text, hex colours, 
custom date formats.

The problem:

Image you have a struct called House

struct House {
let color: UIColor
}

and it has a properly called color and the color represented in JSON as hex 
value (#ff). Currently to make it working you have to extract the underline 
value (string with a hex value) and then try to make a UIColor from it. It 
works but it makes you to copy/past a lot of code and it leads to problems. 
Also it shifts focus from what to decode to how to decode.

The suggested solution:

I suggest that we have to introduce protocols for classes that will encapsulate 
transformation from a source data type to a destination data type. The source 
data types are all existing data that support of decoding. 

We will provide only protocols (one for decoding and one for encoding) and 
users will be able to create transformers for their own data types.

The implementation:

The implementation is fairly easy. We only need introduce two protocols 
(encoding/decoding) and add a method to KeyedEncodingContainerProtocol that 
will accept a key and a transformer. In the method we will extract source data 
from JSON and then will ask the transformer to try to convert it to the desire 
data type.

Example of the decoding protocol:

protocol DecodingTransformer {
associatedtype Input: Decodable
associatedtype Output
func transform(_ decoded: Input) throws -> Output
}


Inspired by: https://github.com/Hearst-DD/ObjectMapper#custom-transforms 


Cheers,
Arsen___
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