Merge pull request #335 from catostrophe/fs2-pre

Add Pre syntax for attaching fs2.Stream algebras
tofu-tf · Aug 6, 2020 · f5f3396 · f5f3396
2 parents 410a27d + 2329a3a
commit f5f3396
Showing 1 changed file with 13 additions and 0 deletions.
diff --git a/fs2/src/main/scala/tofu/fs2Syntax/pre.scala b/fs2/src/main/scala/tofu/fs2Syntax/pre.scala
@@ -0,0 +1,13 @@
+package tofu.fs2Syntax
+
+import cats.tagless.ApplyK
+import fs2.Stream
+import tofu.higherKind.Pre.T
+import tofu.syntax.funk.funK
+
+object pre {
+  implicit final class TofuPreStreamSyntax[F[_], U[f[_]]](private val self: U[T[F, *]]) extends AnyVal {
+    def attachStream(alg: U[Stream[F, *]])(implicit U: ApplyK[U]): U[Stream[F, *]] =
+      U.map2K(self, alg)(funK(t2k => Stream.eval_(t2k.first.value) ++ t2k.second))
+  }
+}