Is this a bad idea: ```inline fun <reified T : ...

# komapper

[dave08]

Is this a bad idea:

inline fun <reified T : Any> literal(value: T): ColumnExpression<T, T> {
        val operand = Operand.SimpleArgument(T::class, value)
        return columnExpression(T::class, "literalObject", listOf(operand)) {
            visit(operand)
        }
    }

to use in selectAsXXX functions... I need to put in literals when I use that with

QueryDsl.insert(...).select { 
... // here often I need these literals like value classes, or enums... I use a query with selectAsXXX
}

[dave08]

It doesn't seem to work... im trying to use it for an enum field but it gives me an illegal state exception that the datatype is not found for the type... from Defaultr2dbcdataoperator.getdatatype()

[Toshihiro Nakamura]

Assuming there is the following Enum type, entity class, and function.

enum class Color {
    RED, BLUE
}

@KomapperEntity
@KomapperProjection
data class Box(
    @KomapperId
    @KomapperAutoIncrement
    val id: Int = 0,
    @KomapperEnum(type = EnumType.NAME)
    val color : Color,
)

// ColumnExpression for a generic Enum type
fun <E : Enum<E>> bindEnum(expression: ColumnExpression<E, *>, value: E): ColumnExpression<E, *> {
    val operand = Operand.Argument(expression, value)
    return columnExpression(expression,"bindEnum", listOf(operand)) {
        visit(operand)
    }
}

Use the above bindEnum function as follows:

database.runQuery {
    QueryDsl.insert(b).select {
        QueryDsl.from(b).selectAsBox(id = b.id, color = bindEnum(b.color, Color.BLUE))
    }
}

[dave08]

Thanks! That seems to work... it might be nice to add that to the next version...?