fork mustache

1 files changed, 72 insertions, 0 deletions

diff --git a/mustache/app/Main.hs b/mustache/app/Main.hs
new file mode 100644
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--- /dev/null
+++ b/mustache/app/Main.hs
@@ -0,0 +1,72 @@
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE NamedFieldPuns     #-}
+module Main (main) where
+
+
+import           Data.Aeson                      (Value, eitherDecode)
+import           Data.Bifunctor                  (first)
+import qualified Data.ByteString                 as B (readFile)
+import qualified Data.ByteString.Lazy            as BS (readFile)
+import           Data.Foldable                   (for_)
+import qualified Data.Text.IO                    as TIO (putStrLn)
+import           Data.Yaml                       (decodeEither')
+
+import           System.Console.CmdArgs.Implicit (Data, Typeable, argPos, args,
+                                                  cmdArgs, def, help, summary,
+                                                  typ, (&=))
+import           System.FilePath                 (takeExtension)
+import           Text.Mustache                   (automaticCompile, substitute,
+                                                  toMustache)
+
+
+data Arguments = Arguments
+  { template     :: FilePath
+  , templateDirs :: [FilePath]
+  , dataFiles    :: [FilePath]
+  } deriving (Show, Data, Typeable)
+
+
+commandArgs :: Arguments
+commandArgs = Arguments
+  { template = def
+      &= argPos 0
+      &= typ "TEMPLATE"
+  , dataFiles = def
+      &= args
+      &= typ "DATA-FILES"
+  , templateDirs = ["."]
+      &= help "The directories in which to search for the templates"
+      &= typ "DIRECTORIES"
+  } &= summary "Simple mustache template subtitution"
+
+
+readJSON :: FilePath -> IO (Either String Value)
+readJSON = fmap eitherDecode . BS.readFile
+
+
+readYAML :: FilePath -> IO (Either String Value)
+readYAML = fmap (first show . decodeEither') . B.readFile
+
+
+main :: IO ()
+main = do
+  (Arguments { template, templateDirs, dataFiles }) <- cmdArgs commandArgs
+
+  eitherTemplate <- automaticCompile templateDirs template
+
+  case eitherTemplate of
+    Left err -> print err
+    Right compiledTemplate ->
+      for_ dataFiles $ \file -> do
+
+        let decoder =
+              case takeExtension file of
+                ".yml"  -> readYAML
+                ".yaml" -> readYAML
+                _       -> readJSON
+        decoded <- decoder file
+
+        either
+          putStrLn
+          (TIO.putStrLn . substitute compiledTemplate . toMustache)
+          decoded