Add autogenerated build config module with an easily usable format. S…

…tay DRY!

Main.hs

@@ -1,11 +1,12 @@
 module Main where
 
-import Paths_smudge
+import PackageInfo (packageInfo, author, synopsis)
 import Backends.Backend
 import Backends.GraphViz
 import Grammar
 
 import Control.Applicative
+import Distribution.Package (packageVersion, packageName, PackageName(..))
 import Text.ParserCombinators.Parsec (parse, ParseError)
 import System.Console.GetOpt
 import System.Environment
@@ -40,8 +41,13 @@ subcommand name f os = map makeSub os
 data SystemOption = Version | Help
     deriving (Show, Eq)
 
+app_name :: String
+app_name = ((\ (PackageName s) -> s) $ packageName packageInfo)
+
 header :: String
-header = "Usage: [OPTIONS] file"
+header = "Usage: " ++ app_name ++ " [OPTIONS] file\n" ++
+         synopsis ++ "\n" ++
+         "Written by " ++ author ++ "\n"
 
 sysopts :: [OptDescr SystemOption]
 sysopts = [Option ['v'] ["version"] (NoArg Version) "Version information.",
@@ -58,7 +64,7 @@ printUsage :: IO ()
 printUsage = putStr $ usageInfo header all_opts
 
 printVersion :: IO ()
-printVersion = putStrLn ("Version: " ++ showVersion version)
+printVersion = putStrLn (app_name ++ " version: " ++ (showVersion $ packageVersion packageInfo))
 
 main = do
     args <- getArgs

Setup.hs

@@ -1,2 +1,38 @@
-import Distribution.Simple
-main = defaultMain
+import Distribution.PackageDescription (PackageDescription(..))
+import Distribution.Simple (defaultMainWithHooks, simpleUserHooks, UserHooks(..), Args)
+import Distribution.Simple.BuildPaths (autogenModulesDir)
+import Distribution.Simple.LocalBuildInfo (LocalBuildInfo)
+import Distribution.Simple.Setup (BuildFlags(..), fromFlag)
+import Distribution.Simple.Utils (createDirectoryIfMissingVerbose, rewriteFile)
+import System.FilePath ((</>), (<.>))
+
+main = defaultMainWithHooks packageInfoUserHooks
+
+packageInfoUserHooks :: UserHooks
+packageInfoUserHooks =
+    simpleUserHooks {
+        buildHook = genPackageInfoHook
+    }
+
+genPackageInfoHook :: PackageDescription -> LocalBuildInfo -> UserHooks -> BuildFlags -> IO ()
+genPackageInfoHook pkg lbi uhs bfs= do
+    createDirectoryIfMissingVerbose (fromFlag $ buildVerbosity bfs) True (autogenModulesDir lbi)
+    let packageInfoModulePath = autogenModulesDir lbi </> cfg_name <.> "hs"
+    rewriteFile packageInfoModulePath (generate pkg)
+    buildHook simpleUserHooks pkg lbi uhs bfs
+    where cfg_name = "PackageInfo"
+          generate pkg = "module " ++ cfg_name ++ " where\n" ++
+                         "\n" ++
+                         "import Distribution.Package (PackageIdentifier(..), PackageName(..))\n" ++
+                         "import Distribution.Version (Version(..))\n" ++
+                         "\n" ++
+                         "packageInfo = " ++ (show $ package pkg) ++ "\n" ++
+                         "copyright   = " ++ (show $ copyright pkg) ++ "\n" ++
+                         "maintainer  = " ++ (show $ maintainer pkg) ++ "\n" ++
+                         "author      = " ++ (show $ author pkg) ++ "\n" ++
+                         "stability   = " ++ (show $ stability pkg) ++ "\n" ++
+                         "homepage    = " ++ (show $ homepage pkg) ++ "\n" ++
+                         "pkgUrl      = " ++ (show $ pkgUrl pkg) ++ "\n" ++
+                         "bugReports  = " ++ (show $ bugReports pkg) ++ "\n" ++
+                         "synopsis    = " ++ (show $ synopsis pkg) ++ "\n" ++
+                         "description = " ++ (show $ description pkg) ++ "\n"

smudge.cabal

@@ -33,7 +33,7 @@ Maintainer:          [email protected]
 
 Category:            Language
 
-Build-type:          Simple
+Build-type:          Custom
 
 -- Extra files to be distributed with the package, such as examples or
 -- a README.
@@ -48,7 +48,7 @@ Executable smudge
   Main-is:           Main.hs
 
   -- Packages needed in order to build this package.
-  Build-depends:     base, containers, filepath, fgl, parsec, text, graphviz <= 2999.15.0.1
+  Build-depends:     base, Cabal, containers, filepath, fgl, parsec, text, graphviz <= 2999.15.0.1
 
   -- Modules not exported by this package.
   Other-modules:     Grammar Backends.Backend Backends.GraphViz