Tuple to HList using productElements

问题

I am using Shapeless 2.2.5. I try to convert a tuple to HList using the code below.

 import shapeless._
import syntax.std.product._

(23, "foo", 2.0, true).productElements

But I get a compilation error.

[error] /scala/testScala/src/test/scala/lombok/shapeless/TestTuple2HList.scala:12: could not find implicit value for parameter gen: shapeless.Generic[(Int, String, Double, Boolean)]
[error]      (23, "foo", 2.0, true).productElements

The test conversions.scala in https://github.com/milessabin/shapeless/blob/master/core/src/test/scala/shapeless/conversions.scala

did not provide an implicit value for Generic[(Int,String,Double,Boolean)].

Have I missed some imports ?

Thanks in advance for any assistance !

Shing

回答1:

It should be import syntax.std.tuple._ rather than import syntax.std.product._.

来源：https://stackoverflow.com/questions/35258391/tuple-to-hlist-using-productelements