Heyo! I was wondering if it was possible on an anonymous function to make the return type be annotat...

# getting-started

[Tech]

Heyo!
I was wondering if it was possible on an anonymous function to make the return type be annotated with the @Language tag, I'm trying to do something like this with no luck so far.

typealias Test = () -> @receiver:Language("SQL") String

fun example(l: Test) {
    println(l())
}

The syntax of

example {
  "SELECT"
}

doesn't have the SQL highlighting.

[Adam S]

Short answer: no. The best you can do is to add /* language=SQL */ before the String. (And you can collapse the comment to make it more subtle)

[Adam S]

The @Language annotation is written in Java, and annotation-detector in IntelliJ util doesn't recognise the annotation when it's added to Kotlin-specific concepts. I think this is the issue relevant to your question https://youtrack.jetbrains.com/issue/KTIJ-5644/Support-language-injection-on-operator-functions

However... KMP support is in progress https://github.com/JetBrains/java-annotations/pull/103, so, maybe one day!

[Adam S]

tbh I don't think that @receiver:Language("SQL") would be right even if IntelliJ did fully support Kotlin 🤔 There's no receiver in () -> String.

What you'd want is typealias Tmp = () -> @Language("SQL") String - but, even if IntelliJ did recognise it, it won't compile because there's an error: "This annotation is not applicable to target 'type usage'"

[dave08]

Maybe wrap it with a value class with it's string property annotated, would that work? That wouldn't waste an allocation either...

[dave08]

import org.intellij.lang.annotations.Language

@JvmInline
value class Sql(@Language("SQL") val value: String)

fun example(l: () -> Sql) {
    val sql = l()
    println(sql.value)
}

example { 
    Sql("SELECT * FROM foo")
}

You can even override unaryPlus in a dsl scope in example to write +"SELECT..." I think

[Tech]

Interesting suggestions,

@dave08 I was actually experimenting with having a sql function, in all reality what you need to do is just this.

fun sql(@Language("SQL") sql: String) = sql

And you'll get the syntax highlighting.

@Adam S Interesting, I didn't know /* language=SQL */ was a thing but unfortunately I don't think that'd be very good DevEx, what I'm probably going to do is just use a global function like the one I just stated to do something like this,

example {
  sql("""
    SELECT * FROM test;
  """.trim())
}

Thank you for the help though, this is a pretty obscure use-case 😅

[Tech]

Overriding the unary does sound kind of interesting though, may play with that but I don't think it'll work

[dave08]

It should work like the function, but I wouldn't do that at top level...

[dave08]

Just in a DSL

[Tech]

Ah I get what you mean

[Tech]

I'll play around with it later

[dave08]

Good luck!

[Tech]

🫡