add Haskell snippet to check if a file exists

Author: ACR1209

snippets/haskell/file-handling/file-exists.md

@@ -0,0 +1,19 @@
+---
+title: Check if File Exists
+description: Checks if a file exists at a given path.
+author: ACR1209
+tags: haskell,file,exists
+---
+
+```hs
+import System.Directory (doesFileExist)
+
+checkFileExists :: FilePath -> IO Bool
+checkFileExists = doesFileExist
+
+main :: IO ()
+main = do
+    let file = "example.txt"
+    exists <- checkFileExists file
+    if exists then putStrLn "File exists." else putStrLn "File does not exist."
+```