add Scheme.toString

src/URI/Scheme.purs

@@ -1,6 +1,7 @@
 module URI.Scheme
   ( Scheme
   , fromString
+  , toString
   , unsafeFromString
   , parser
   , print
@@ -42,6 +43,15 @@ instance showScheme ∷ Show Scheme where
 fromString ∷ String → Maybe Scheme
 fromString = map Scheme <<< hush <<< flip runParser (parseScheme <* eof)
 
+-- | Returns the string value for a scheme.
+-- |
+-- | ``` purescript
+-- | toString (unsafeFromString "http") == "http"
+-- | toString (unsafeFromString "git+ssh") == "git+ssh"
+-- | ```
+toString ∷ Scheme → NonEmptyString
+toString (Scheme s) = s
+
 -- | Constructs a `Scheme` part unsafely: if the value is not an acceptable
 -- | scheme a runtime error will be thrown.
 -- |

test/URI/Scheme.purs

@@ -2,12 +2,21 @@ module Test.URI.Scheme where
 
 import Prelude
 
-import Test.Spec (Spec, describe)
-import Test.Util (testIso)
+import Data.Maybe (Maybe(..))
+import Data.String.NonEmpty as NES
+import Test.Spec (Spec, describe, it)
+import Test.Util (testIso, equal)
 import URI.Scheme as Scheme
 
 spec ∷ ∀ eff. Spec eff Unit
-spec =
+spec = do
   describe "Scheme parser/printer" do
     testIso Scheme.parser Scheme.print "http:" (Scheme.unsafeFromString "http")
     testIso Scheme.parser Scheme.print "git+ssh:" (Scheme.unsafeFromString "git+ssh")
+  describe "Scheme fromString/toString" do
+    it "http"
+      let http = Scheme.unsafeFromString "http"
+      in equal (Just http) $ Scheme.fromString $ NES.toString $ Scheme.toString http
+    it "git+ssh"
+      let git = Scheme.unsafeFromString "git+ssh"
+      in equal (Just git) $ Scheme.fromString $ NES.toString $ Scheme.toString git