Search for terms from a tags file

This returns a list of each match, files, and counts based on the
current directory.

app/Main.hs

@@ -1,6 +1,9 @@
 module Main where
 
-import Lib
+import Unused.TermSearch (search)
 
 main :: IO ()
-main = someFunc
+main = do
+    tokens <- pure . lines =<< getContents
+    results <- pure . concat =<< mapM search tokens
+    putStrLn $ unlines results

src/Lib.hs

@@ -1,6 +0,0 @@
-module Lib
-    ( someFunc
-    ) where
-
-someFunc :: IO ()
-someFunc = putStrLn "someFunc"

src/Unused/TermSearch.hs

@@ -0,0 +1,24 @@
+module Unused.TermSearch
+    ( search
+    ) where
+
+import System.IO
+import System.Process
+
+search :: String -> IO [String]
+search t = do
+    results <- ag t
+    return $ linesMap prefixTerm results
+  where
+    prefixTerm = ((++) t)
+
+linesMap :: (String -> String) -> String -> [String]
+linesMap f =
+    filter empty . map f . lines
+  where
+    empty = ((/=) 0) . length
+
+ag :: String -> IO String
+ag t = do
+  (_, results, _) <- readProcessWithExitCode "ag" [t, ".", "-c", "-Q", "--ackmate"] ""
+  return results

unused.cabal

@@ -15,8 +15,9 @@ cabal-version:       >=1.10
 
 library
   hs-source-dirs:      src
-  exposed-modules:     Lib
+  exposed-modules:     Unused.TermSearch
   build-depends:       base >= 4.7 && < 5
+                     , process
   default-language:    Haskell2010
 
 executable unused