Dotty: Missing LINQ QueryDSL with Scala3

[netroby]

Hello, I know scala have Slick , but it's too ugly than C# LINQ.
Here is the Scala SLICK syntax:

val q = for {
    c <- Coffees if c.supID === 101
} yield (c.name, c.price)

This would be equivalent to the following C#:

// LINQ extension method syntax
var q = Coffees.Where(c => c.supID == 101)
               .Select(c => new { c.name, c.Price});

// LINQ query syntax
var q = from c in Coffees 
          where c.supId == 101 
          select new { c.name, c.price};

Yield and Select appear to be the same sort of projection routine.

Personally, I think the Scala one feels ugly, but that might only be because both C# options are so readable.

Now Groovy have GINQ , Looks good.

import groovy.transform.*
@TupleConstructor
@EqualsAndHashCode
@ToString
class Person {
    String name
    String nickname
}

def linda = new Person('Linda', null)
def david = new Person('David', null)
def persons = [new Person('Daniel', 'ShanFengXiaoZi'), linda, david]
def result = GQ {
    from p in persons
    where p.nickname == null
    select p
}.stream()
    .peek(p -> { p.nickname = 'Unknown' }) // update `nickname`
    .toList()

def expected = [new Person('Linda', 'Unknown'), new Person('David', 'Unknown')]
assert expected == result
assert ['Unknown', 'Unknown'] == [linda, david]*.nickname // ensure the original objects are updated

So i wonder if Scala 3 can support some feature like LINQ, Or learn from Groovy lang.

The QueryDSL was the big missing part of Scala .

http://mail-archives.apache.org/mod_mbox/groovy-notifications/201907.mbox/%[email protected]%3E

[jira] [Updated] (GROOVY-9159) [GEP] Support LINQ, aka GINQ

https://docs.groovy-lang.org/docs/next/html/documentation/#_querying_collections_in_a_sql_like_style

[odersky]

Please consider re-submitting this issue as a feature request.

[liufengyun]

@netroby You should have a look at Quill, which is better and more powerful.

https://github.com/getquill/quill

[netroby]

@liufengyun The quill did not right design. LINQ has it's style. LINQ is unique technology.

I can only see C#, and groovy design the good practice.

I hope scala has the right design practice. Nor Slick ethier Quill.

They were not the same thing equal to LINQ.

[netroby]

I create a new Issue https://github.com/lampepfl/dotty-feature-requests/issues/154

Hope this missing part to be fixed.

[liufengyun]

The quill did not right design. LINQ has it's style. LINQ is unique technology.

I can only see C#, and groovy design the good practice.

Quill is based on the latest research on Language-Integrated Query (LINQ):

https://github.com/getquill/quill#acknowledgments

If you propose something that is different, you need to justify your claim carefully against the latest research results and implementation (in the feature request).