SQL macro

gistfile1.scala

object Sql {
  import scala.reflect.makro._
  import language.experimental.macros

  case class Query[R](/*sql: String*/)

  def execute[R](q: Query[R]): Seq[R] = sys.error("implement me")

  def sqlImpl(c: Context)(s: c.Expr[String]): c.Expr[Any] = {
    import c.universe._
    val Literal(Constant(sql: String)) = s.tree

    // Real impl would parse SQL and infer types from db schema
    if (sql.contains("id,name")) c.reify(Query[(Long, String)]())
    else c.reify(Query[Long]())
  }

  def sql(s: String) = macro sqlImpl
}

scala> import Sql._
import Sql._

scala> sql("select id,name from user")
res0: Sql.Query[(Long, String)] = Query()

scala> sql("select id from user")
res1: Sql.Query[Long] = Query()