Simplified some expressions with LambdaCase language extension

Author: ameingast

postgresql-simple-migration.cabal

@@ -35,7 +35,7 @@ Library
                             Database.PostgreSQL.Simple.Util
     hs-source-dirs:         src
     ghc-options:            -Wall -fwarn-tabs -fwarn-incomplete-uni-patterns
-    default-extensions:     OverloadedStrings, CPP
+    default-extensions:     OverloadedStrings, CPP, LambdaCase
     default-language:       Haskell2010
     build-depends:          base                        >= 4.6      && < 5.0,
                             base64-bytestring           >= 1.0      && < 1.1,
@@ -49,7 +49,7 @@ Executable migrate
     main-is:                Main.hs
     hs-source-dirs:         src
     ghc-options:            -Wall -fwarn-tabs -fwarn-incomplete-uni-patterns
-    default-extensions:     OverloadedStrings, CPP
+    default-extensions:     OverloadedStrings, CPP, LambdaCase
     default-language:       Haskell2010
     build-depends:          base                        >= 4.6      && < 5.0,
                             base64-bytestring           >= 1.0      && < 1.1,
@@ -64,7 +64,7 @@ test-suite tests
     main-is:                Main.hs
     hs-source-dirs:         test
     ghc-options:            -Wall -fwarn-tabs -fwarn-incomplete-uni-patterns
-    default-extensions:     OverloadedStrings, CPP
+    default-extensions:     OverloadedStrings, CPP, LambdaCase
     default-language:       Haskell2010
     type:                   exitcode-stdio-1.0
     build-depends:          base                        >= 4.6      && < 5.0,

src/Database/PostgreSQL/Simple/Migration.hs

@@ -13,6 +13,7 @@
 
 {-# LANGUAGE CPP               #-}
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE LambdaCase        #-}
 
 module Database.PostgreSQL.Simple.Migration
     (
@@ -101,7 +102,7 @@ scriptsInDirectory dir =
 executeMigration :: Connection -> Bool -> ScriptName -> BS.ByteString -> IO (MigrationResult String)
 executeMigration con verbose name contents = do
     let checksum = md5Hash contents
-    checkScript con name checksum >>= \r -> case r of
+    checkScript con name checksum >>= \case
         ScriptOk -> do
             when verbose $ putStrLn $ "Ok:\t" ++ name
             return MigrationSuccess
@@ -155,7 +156,7 @@ executeValidation con verbose cmd = case cmd of
         return MigrationSuccess
     where
         validate name contents =
-            checkScript con name (md5Hash contents) >>= \r -> case r of
+            checkScript con name (md5Hash contents) >>= \case
                 ScriptOk -> do
                     when verbose $ putStrLn $ "Ok:\t" ++ name
                     return MigrationSuccess
@@ -168,8 +169,7 @@ executeValidation con verbose cmd = case cmd of
 
         goScripts _ [] = return MigrationSuccess
         goScripts path (x:xs) = do
-            r <- validate x =<< BS.readFile (path ++ "/" ++ x)
-            case r of
+            (validate x =<< BS.readFile (path ++ "/" ++ x)) >>= \case
                 e@(MigrationError _) ->
                     return e
                 MigrationSuccess ->
@@ -182,7 +182,7 @@ executeValidation con verbose cmd = case cmd of
 -- will be executed and its meta-information will be recorded.
 checkScript :: Connection -> ScriptName -> Checksum -> IO CheckScriptResult
 checkScript con name checksum =
-    query con q (Only name) >>= \r -> case r of
+    query con q (Only name) >>= \case
         [] ->
             return ScriptNotExecuted
         Only actualChecksum:_ | checksum == actualChecksum ->

src/Database/PostgreSQL/Simple/Util.hs

@@ -11,6 +11,7 @@
 
 {-# LANGUAGE CPP               #-}
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE LambdaCase        #-}
 
 module Database.PostgreSQL.Simple.Util
     ( existsTable

src/Main.hs

@@ -11,6 +11,7 @@
 
 {-# LANGUAGE CPP               #-}
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE LambdaCase        #-}
 
 module Main (
     main
@@ -35,7 +36,7 @@ import qualified Data.Text                            as T
 import qualified Data.Text.Encoding                   as T
 
 main :: IO ()
-main = getArgs >>= \args -> case args of
+main = getArgs >>= \case
     "-h":_ ->
         printUsage
     "-q":xs ->

test/Database/PostgreSQL/Simple/MigrationTest.hs

@@ -10,7 +10,8 @@
 -- A collection of postgresql-simple-migration specifications.
 
 {-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE CPP #-}
+{-# LANGUAGE CPP               #-}
+{-# LANGUAGE LambdaCase        #-}
 
 module Database.PostgreSQL.Simple.MigrationTest where
 

test/Main.hs

@@ -10,7 +10,8 @@
 -- The test entry-point for postgresql-simple-migration.
 
 {-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE CPP #-}
+{-# LANGUAGE CPP               #-}
+{-# LANGUAGE LambdaCase        #-}
 
 module Main
     ( main