read-env-var (empty) → 0.1.0.0

raw patch · 5 files changed

+169/−0 lines, 5 filesdep +Globdep +basedep +doctestsetup-changed

Dependencies added: Glob, base, doctest

Files

LICENSE +30/−0
Setup.hs +2/−0
read-env-var.cabal +35/−0
src/System/ReadEnvVar.hs +62/−0
test/DocTest.hs +40/−0

+ LICENSE view

@@ -0,0 +1,30 @@+Copyright Author name here (c) 2016++All rights reserved.++Redistribution and use in source and binary forms, with or without+modification, are permitted provided that the following conditions are met:++    * Redistributions of source code must retain the above copyright+      notice, this list of conditions and the following disclaimer.++    * Redistributions in binary form must reproduce the above+      copyright notice, this list of conditions and the following+      disclaimer in the documentation and/or other materials provided+      with the distribution.++    * Neither the name of Author name here nor the names of other+      contributors may be used to endorse or promote products derived+      from this software without specific prior written permission.++THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

+ Setup.hs view

@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain

+ read-env-var.cabal view

@@ -0,0 +1,35 @@+name:                read-env-var+version:             0.1.0.0+synopsis:            Functions for safely reading environment variables.+description:         Please see README.md+homepage:            https://github.com/cdepillabout/read-env-var#readme+license:             BSD3+license-file:        LICENSE+author:              Dennis Gosnell+maintainer:          cdep.illabout@gmail.com+copyright:           2016 Dennis Gosnell+category:            System+build-type:          Simple+-- extra-source-files:+cabal-version:       >=1.10++library+  hs-source-dirs:      src+  exposed-modules:     System.ReadEnvVar+  build-depends:       base >= 4.6 && < 5+  default-language:    Haskell2010+  ghc-options:         -Wall++test-suite read-env-var-doctest+  type:                exitcode-stdio-1.0+  main-is:             DocTest.hs+  hs-source-dirs:      test+  build-depends:       base+                     , doctest+                     , Glob+  default-language:    Haskell2010+  ghc-options:         -Wall -threaded -rtsopts -with-rtsopts=-N++source-repository head+  type:     git+  location: git@github.com:cdepillabout/read-env-var.git

+ src/System/ReadEnvVar.hs view

@@ -0,0 +1,62 @@+{-# LANGUAGE CPP #-}++{-|+Module      : System.ReadEnvVar+Copyright   : (c) Dennis Gosnell, 2016+License     : BSD-style (see LICENSE file)+Maintainer  : cdep.illabout@gmail.com+Stability   : experimental+Portability : POSIX++This Haskell module exports functions for safely reading environment variables.+-}++module System.ReadEnvVar+    ( readEnvVar+    , readEnvVarDef+    ) where++#if __GLASGOW_HASKELL__ < 710+-- We don't need this import for GHC 7.10 as it exports all required functions+-- from Prelude+import Control.Applicative+#endif++import Data.Maybe (fromMaybe)+import System.Environment (lookupEnv)+import Text.Read (readMaybe)++-- | Lookup a value from an environment variable and read it in with+-- 'readMaybe'.  If the environment variable doesn't exist, or it can't be+-- 'read', use the default value.+--+-- >>> import System.Environment (setEnv)+-- >>> setEnv "TEST_ENV_VAR" "1000"+-- >>> readEnvVarDef "TEST_ENV_VAR" 5 :: IO Int+-- 1000+-- >>> readEnvVarDef "THIS_ENV_VAR_WILL_NOT_EXIST" 5 :: IO Int+-- 5+readEnvVarDef :: Read a+              => String -- ^ environment variable to lookup+              -> a      -- ^ default value to use if the environment variable+                        -- either does not exist, or cannot be 'read'+              -> IO a+readEnvVarDef envVar def = fromMaybe def <$> readEnvVar envVar++-- | Lookup a value from an environment variable and read it in with+-- 'readMaybe'.+--+-- >>> import System.Environment (setEnv)+-- >>> setEnv "TEST_ENV_VAR" "2000"+-- >>> readEnvVar "TEST_ENV_VAR" :: IO (Maybe Int)+-- Just 2000+-- >>> readEnvVar "THIS_ENV_VAR_WILL_NOT_EXIST" :: IO (Maybe Int)+-- Nothing+readEnvVar :: Read a+           => String       -- ^ environment variable to lookup+           -> IO (Maybe a)+readEnvVar envVar = do+    maybeEnvVal <- lookupEnv envVar+    case maybeEnvVal of+        Nothing -> return Nothing+        Just envVal -> return $ readMaybe envVal

+ test/DocTest.hs view

@@ -0,0 +1,40 @@++module Main (main) where++import Prelude++import Data.Monoid ((<>))+import System.FilePath.Glob (glob)+import Test.DocTest (doctest)++main :: IO ()+main = glob "src/**/*.hs" >>= doDocTest++doDocTest :: [String] -> IO ()+doDocTest options = doctest $ options <> ghcExtensions++ghcExtensions :: [String]+ghcExtensions =+    [+    --   "-XConstraintKinds"+    -- , "-XDataKinds"+      "-XDeriveDataTypeable"+    , "-XDeriveGeneric"+    -- , "-XEmptyDataDecls"+    , "-XFlexibleContexts"+    -- , "-XFlexibleInstances"+    -- , "-XGADTs"+    -- , "-XGeneralizedNewtypeDeriving"+    -- , "-XInstanceSigs"+    -- , "-XMultiParamTypeClasses"+    -- , "-XNoImplicitPrelude"+    , "-XOverloadedStrings"+    -- , "-XPolyKinds"+    -- , "-XRankNTypes"+    -- , "-XRecordWildCards"+    , "-XScopedTypeVariables"+    -- , "-XStandaloneDeriving"+    -- , "-XTupleSections"+    -- , "-XTypeFamilies"+    -- , "-XTypeOperators"+    ]