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/* NSC -- new Scala compiler
* Copyright 2005-2011 LAMP/EPFL
* @author Martin Odersky
*/
package scala.reflect
package api
trait Exprs { self: Universe =>
/** An expression tree tagged with its type */
case class Expr[+T: TypeTag](tree: Tree) {
def tpe: Type = implicitly[TypeTag[T]].tpe
def eval: T = mkToolBox().runExpr(tree).asInstanceOf[T]
lazy val value: T = eval
override def toString = "Expr["+tpe+"]("+tree+")"
}
// [Eugene] had to move this to the companion of Tree to make stuff compile. weirdo!
// object Expr {
// // would be great if in future this generated an Expr[Magic]
// // where Magic is a magic untyped type that propagates through the entire quasiquote
// // and turns off typechecking whenever it's involved
// // that'd allow us to splice trees into quasiquotes and still have these qqs to be partially typechecked
// // see some exploration of these ideas here: https://github.com/xeno-by/alphakeplerdemo
// implicit def tree2expr(tree: Tree): Expr[Nothing] = Expr[Nothing](tree)
// implicit def expr2tree(expr: Expr[_]): Tree = expr.tree
//
// // [Eugene] good idea?
// implicit def trees2exprs(trees: List[Tree]): List[Expr[Nothing]] = trees map tree2expr
// implicit def exprs2trees(exprs: List[Expr[_]]): List[Tree] = exprs map expr2tree
// }
// [Eugene] even weirder - implicits didn't feel at home in Trees :(
// would be great if in future this generated an Expr[Magic]
// where Magic is a magic untyped type that propagates through the entire quasiquote
// and turns off typechecking whenever it's involved
// that'd allow us to splice trees into quasiquotes and still have these qqs to be partially typechecked
// see some exploration of these ideas here: https://github.com/xeno-by/alphakeplerdemo
implicit def tree2expr(tree: Tree): Expr[Nothing] = Expr[Nothing](tree)(TypeTag.Nothing)
implicit def expr2tree(expr: Expr[_]): Tree = expr.tree
// [Eugene] good idea?
implicit def trees2exprs(trees: List[Tree]): List[Expr[Nothing]] = trees map tree2expr
implicit def exprs2trees(exprs: List[Expr[_]]): List[Tree] = exprs map expr2tree
}
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