Resolving variables in scope modified by Scala macro -


i'm investigating possibility make following kind of imports compile in scala:

def helpers[t] = new { def foo: t = ??? } import helpers[int]._

this arose idea pin down types scala not infer on own. manually expanded version works:

val m = helpers[int] import m._ (foo: int)

however, naive attempt @ macro failed:

import scala.reflect.macros.blackbox.context  object open {   def open[t](m: any)(t: t): t = macro open_impl[t]    def open_impl[t](c: context)(m: c.tree)(t: c.tree): c.tree = {     import c.universe._     val freshname = termname(c.freshname("import$"))     q"{ val $freshname = $m; import $freshname._; $t }"   } }

the syntax had in mind let open m in-syntax ocaml. problem being binding of variables seems happen before macro expansion:

import open._ object foo { val x = 7 } open(foo) { println(x) }

fails in repl with:

<console>:16: error: not found: value x        open(foo) { println(x) }

any ideas how work around this? @ possible macros? or perhaps compiler plugin?


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