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import scala.language.experimental.macros
import scala.reflect.macros.whitebox.Context
object Macros {
def foo(name: String): Any = macro foo_impl
def foo_impl(c: Context)(name: c.Expr[String]) = {
import c.universe._
val Literal(Constant(lit: String)) = name.tree
val anon = newTypeName(c.fresh)
c.Expr(Block(
ClassDef(
Modifiers(Flag.FINAL), anon, Nil, Template(
Nil, noSelfType, List(
DefDef(Modifiers(), termNames.CONSTRUCTOR, List(), List(List()), TypeTree(), Block(List(pendingSuperCall), Literal(Constant(())))),
TypeDef(Modifiers(), TypeName(lit), Nil, TypeTree(typeOf[Int]))
)
)
),
Apply(Select(New(Ident(anon)), termNames.CONSTRUCTOR), Nil)
))
}
def bar(name: String): Any = macro bar_impl
def bar_impl(c: Context)(name: c.Expr[String]) = {
import c.universe._
val Literal(Constant(lit: String)) = name.tree
val anon = newTypeName(c.fresh)
c.Expr(Block(
ClassDef(
Modifiers(Flag.FINAL), anon, Nil, Template(
Nil, noSelfType, List(
DefDef(Modifiers(), termNames.CONSTRUCTOR, List(), List(List()), TypeTree(), Block(List(pendingSuperCall), Literal(Constant(())))),
DefDef(
Modifiers(), TermName(lit), Nil, Nil, TypeTree(),
c.literal(42).tree
)
)
)
),
Apply(Select(New(Ident(anon)), termNames.CONSTRUCTOR), Nil)
))
}
def baz(name: String): Any = macro baz_impl
def baz_impl(c: Context)(name: c.Expr[String]) = {
import c.universe._
val Literal(Constant(lit: String)) = name.tree
val anon = newTypeName(c.fresh)
val wrapper = newTypeName(c.fresh)
c.Expr(Block(
ClassDef(
Modifiers(), anon, Nil, Template(
Nil, emptyValDef, List(
DefDef(Modifiers(), termNames.CONSTRUCTOR, List(), List(List()), TypeTree(), Block(List(pendingSuperCall), Literal(Constant(())))),
DefDef(
Modifiers(), TermName(lit), Nil, Nil, TypeTree(),
c.literal(42).tree
)
)
)
),
ClassDef(
Modifiers(Flag.FINAL), wrapper, Nil,
Template(Ident(anon) :: Nil, noSelfType, DefDef(Modifiers(), termNames.CONSTRUCTOR, List(), List(List()), TypeTree(), Block(List(pendingSuperCall), Literal(Constant(())))) :: Nil)
),
Apply(Select(New(Ident(wrapper)), termNames.CONSTRUCTOR), Nil)
))
}
}
|
