From 45eb4889b08e6290ae9c11f59fca9203bd75b8cc Mon Sep 17 00:00:00 2001
From: Ahn Kiwook <ahnkiwook@gmail.com>
Date: Wed, 1 Mar 2017 02:48:37 +0900
Subject: [PATCH] Add Nirum.Constructs.ModulePath.spreadModulePath

---
 src/Nirum/Constructs/ModulePath.hs      | 8 ++++++++
 test/Nirum/Constructs/ModulePathSpec.hs | 9 +++++++++
 2 files changed, 17 insertions(+)

diff --git a/src/Nirum/Constructs/ModulePath.hs b/src/Nirum/Constructs/ModulePath.hs
index 2139030..aac5508 100644
--- a/src/Nirum/Constructs/ModulePath.hs
+++ b/src/Nirum/Constructs/ModulePath.hs
@@ -7,6 +7,7 @@ module Nirum.Constructs.ModulePath ( ModulePath ( ModuleName
                                    , ancestors
                                    , fromFilePath
                                    , fromIdentifiers
+                                   , spreadModulePath
                                    ) where
 
 import Data.Char (toLower)
@@ -66,3 +67,10 @@ instance IsList ModulePath where
                   (fromIdentifiers identifiers)
     toList (ModuleName identifier) = [identifier]
     toList (ModulePath path' identifier) = toList path' ++ [identifier]
+
+spreadModulePath :: ModulePath ->  S.Set [Identifier]
+spreadModulePath modulePath' = S.fromList $ getPathList modulePath'
+  where
+    getPathList :: ModulePath -> [[Identifier]]
+    getPathList m@(ModulePath path' _) = toList m : getPathList path'
+    getPathList (ModuleName identifier) = [[identifier]]
diff --git a/test/Nirum/Constructs/ModulePathSpec.hs b/test/Nirum/Constructs/ModulePathSpec.hs
index 8a6b64b..681674b 100644
--- a/test/Nirum/Constructs/ModulePathSpec.hs
+++ b/test/Nirum/Constructs/ModulePathSpec.hs
@@ -3,8 +3,10 @@ module Nirum.Constructs.ModulePathSpec where
 
 import Control.Exception (evaluate)
 import Data.List (sort)
+import Data.Maybe (fromJust)
 import GHC.Exts (IsList (fromList, toList))
 
+import qualified Data.Set as S
 import System.FilePath ((</>))
 import Test.Hspec.Meta
 
@@ -13,6 +15,7 @@ import Nirum.Constructs.ModulePath ( ModulePath (ModuleName, ModulePath)
                                    , ancestors
                                    , fromFilePath
                                    , fromIdentifiers
+                                   , spreadModulePath
                                    )
 
 spec :: Spec
@@ -82,3 +85,9 @@ spec =
                 fooBarBaz2 `shouldNotSatisfy` (<= fooBarBaz)
                 sort [["abc"], foo, fooBar, fooBarBaz, fooBarBaz2]
                     `shouldBe` [["abc"], foo, fooBar, fooBarBaz, fooBarBaz2]
+        specify "spreadModulePath" $ do
+            let foo' = fromJust $ fromIdentifiers ["foo", "bar", "baz"]
+            spreadModulePath foo' `shouldBe` S.fromList [ ["foo", "bar", "baz"]
+                                                        , ["foo", "bar"]
+                                                        , ["foo"]
+                                                        ]