commit 684f90ec80cd696e2ec0277b3136d85a96b282ef
parent 8064dc247437f3ecd9b8cda573fa189d1c47e859
Author: Jared Tobin <jared@jtobin.ca>
Date: Sat, 28 Feb 2015 23:48:37 +1300
Add currency converter example.
Diffstat:
7 files changed, 152 insertions(+), 0 deletions(-)
diff --git a/.gitignore b/.gitignore
@@ -0,0 +1,3 @@
+dist
+.sandbox
+.cabal-sandbox
diff --git a/20150227_currency/LICENSE b/20150227_currency/LICENSE
@@ -0,0 +1,20 @@
+Copyright (c) 2015 Jared Tobin
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/20150227_currency/Setup.hs b/20150227_currency/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/20150227_currency/cabal.sandbox.config b/20150227_currency/cabal.sandbox.config
@@ -0,0 +1,25 @@
+-- This is a Cabal package environment file.
+-- THIS FILE IS AUTO-GENERATED. DO NOT EDIT DIRECTLY.
+-- Please create a 'cabal.config' file in the same directory
+-- if you want to change the default settings for this sandbox.
+
+
+local-repo: /Users/jtobin/projects/praxis/20150227_currency/.cabal-sandbox/packages
+logs-dir: /Users/jtobin/projects/praxis/20150227_currency/.cabal-sandbox/logs
+world-file: /Users/jtobin/projects/praxis/20150227_currency/.cabal-sandbox/world
+user-install: False
+package-db: /Users/jtobin/projects/praxis/20150227_currency/.cabal-sandbox/x86_64-osx-ghc-7.8.3-packages.conf.d
+build-summary: /Users/jtobin/projects/praxis/20150227_currency/.cabal-sandbox/logs/build.log
+
+install-dirs
+ prefix: /Users/jtobin/projects/praxis/20150227_currency/.cabal-sandbox
+ bindir: $prefix/bin
+ libdir: $prefix/lib
+ libsubdir: $abi/$pkgkey
+ libexecdir: $prefix/libexec
+ datadir: $prefix/share
+ datasubdir: $abi/$pkgid
+ docdir: $datadir/doc/$abi/$pkgid
+ htmldir: $docdir/html
+ haddockdir: $htmldir
+ sysconfdir: $prefix/etc
diff --git a/20150227_currency/src-exec/Main.hs b/20150227_currency/src-exec/Main.hs
@@ -0,0 +1,32 @@
+
+module Main where
+
+import Currency
+import Data.Scientific
+import Options.Applicative
+import Options.Applicative.Types
+
+main :: IO ()
+main = execParser parserOptions >>= runProgram
+
+data ExchangeOptions = ExchangeOptions Scientific String String
+
+-- | Options parser options.
+parserOptions :: ParserInfo ExchangeOptions
+parserOptions = info (helper <*> opts) fullDesc where
+ opts =
+ ExchangeOptions
+ <$> argument parseSci (metavar "AMOUNT")
+ <*> argument str (metavar "CURRENCY")
+ <*> argument str (metavar "CURRENCY")
+
+runProgram :: ExchangeOptions -> IO ()
+runProgram (ExchangeOptions d x y) = do
+ val <- query d x y
+ putStrLn $ show d <> "@" <> x <> "/" <> y <> ": " <> show val
+
+parseSci :: ReadM Scientific
+parseSci = do
+ sci <- readerAsk
+ return $ read sci
+
diff --git a/20150227_currency/src-lib/Currency.hs b/20150227_currency/src-lib/Currency.hs
@@ -0,0 +1,35 @@
+{-# OPTIONS_GHC -Wall #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module Currency (query) where
+
+import Control.Lens
+import Data.Aeson
+import Data.Aeson.Lens
+import Data.Monoid
+import Data.Scientific (Scientific)
+import Data.Text (Text)
+import qualified Data.Text as Text
+import Network.Wreq
+
+apiUrl :: String
+apiUrl = "http://www.freecurrencyconverterapi.com/api/v3/convert"
+
+convertQuery :: String -> String -> String
+convertQuery x y = apiUrl <> "?q=" <> x <> "_" <> y <> "&compact=y"
+
+tp :: String -> Text
+tp = Text.pack
+
+query :: Scientific -> String -> String -> IO Scientific
+query d x y = do
+ r <- asJSON =<< get (convertQuery x y) :: IO (Response Value)
+ let replyBody = do
+ reply <- r ^? responseBody . key (tp x <> "_" <> tp y) . _Object
+ val <- reply ^. at "val"
+ val ^? _Number
+
+ case replyBody of
+ Nothing -> error "invalid currency pair"
+ Just v -> return $ d * v
+
diff --git a/20150227_currency/x20150227-currency.cabal b/20150227_currency/x20150227-currency.cabal
@@ -0,0 +1,35 @@
+name: x20150227-currency
+version: 0.1.0.0
+license: MIT
+license-file: LICENSE
+author: Jared Tobin
+maintainer: jared@jtobin.ca
+build-type: Simple
+cabal-version: >=1.10
+
+library
+ exposed-modules: Currency
+ hs-source-dirs: src-lib
+ default-language: Haskell2010
+ build-depends:
+ aeson >= 0.8.0.2
+ , base >= 4.7 && < 4.8
+ , containers >= 0.5.5.1
+ , lens >= 3.7
+ , lens-aeson >= 1.0.0.3
+ , scientific >= 0.3.3.7
+ , text >= 1.2.0.4
+ , wreq >= 0.3.0.1
+
+executable exchange-rate
+ main-is: Main.hs
+ hs-source-dirs: src-exec
+ default-language: Haskell2010
+ ghc-options:
+ -Wall -Werror -O2
+ build-depends:
+ base >= 4.7.0.1 && < 4.8
+ , optparse-applicative >= 0.11.0.1
+ , scientific >= 0.3.3.7
+ , x20150227-currency >= 0.1.0.0
+
