Macro and String interpolation variables

Question

Giving the code

class Test {
  static function main() {
    var i = 1;
    trace(m('some before $i some after')); // some before 1 some after
  }

  static macro function m(e: haxe.macro.Expr)
  {
    trace(e); // { expr => EConst(CString(some before $i some after)), pos => #pos(Test.hx:4: characters 12-39) }

    // trace the name of referenced var
    /* 
    trace();
    */

    return macro $e;
  }
}

what should I place in commented out code to trace() the name of the variable used inside an interpolated String expression without manual parsing of the string constant?

Answer 1

What you want is formatString:

class Test {
  #if !macro
  static function main() {
    var i = 1;
    trace(m('some before $i some after')); // some before 1 some after
  }
  #end
  static macro function m(e: haxe.macro.Expr)
  {
    switch e.expr {
      case EConst(CString(s)):
        trace(haxe.macro.MacroStringTools.formatString(s, e.pos));
      default:
    }
    return e; 
  }
}