Accept Prolog rule file in CLI arguments

spockz · May 31, 2011 · f15302f · f15302f
1 parent 23887b0
commit f15302f
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Showing 2 changed files with 10 additions and 5 deletions.
diff --git a/NanoProlog.cabal b/NanoProlog.cabal
@@ -1,5 +1,5 @@
 Name:                NanoProlog
-Version:             0.2.1
+Version:             0.2.2
 Synopsis:            Very small  interpreter for a Prolog-like language
 Description:         This package was developed to demonstrate the ideas behind
                      the Prolog language. It contains a very small interpreter
@@ -31,6 +31,7 @@ Executable nano-prolog
 
 Library
   Build-Depends:	  base >= 4.0 && < 5.0,
+                    haskell98 >= 1.1.0.1,
                     uu-parsinglib >= 2.7.1,
                     ListLike == 3.1.*,
                     containers == 0.4.*

diff --git a/src/Language/Prolog/NanoProlog/Interpreter.hs b/src/Language/Prolog/NanoProlog/Interpreter.hs
@@ -2,17 +2,21 @@ module Language.Prolog.NanoProlog.Interpreter where
 
 import            Language.Prolog.NanoProlog.NanoProlog
 import            Text.ParserCombinators.UU
+import            System (getArgs)
 import            System.IO
 
 -- * Running the Interpreter
 -- ** The main interpreter
 -- | The `main` program prompt for a file with Prolog rules and call the main
 -- interpreter loop
 run :: IO ()
-run =  do  hSetBuffering stdin LineBuffering
-           putStrLn "File with rules?"
-           fn  <- getLine
-           s   <- readFile fn
+run =  do  args  <- getArgs
+           fn    <- case args of
+                      []     -> do  hSetBuffering stdin LineBuffering
+                                    putStrLn "File with rules?"
+                                    getLine
+                      (x:_)  -> return x
+           s     <- readFile fn
            let (rules, errors) = startParse (pList pRule) s
            if null errors  then  do  mapM_ print rules
                                      loop rules