add --gui option

1 files changed, 15 insertions, 2 deletions

diff --git a/UI.hs b/UI.hs
index 0ce87db..a97f3c1 100644
--- a/UI.hs
+++ b/UI.hs
@@ -10,5 +10,18 @@ import Control.Monad
 import UI.Zenity
 import UI.Readline
 
-availableUI :: IO [UI]
-availableUI = filterM isAvailable [zenityUI, readlineUI]
+availableUIs :: IO [UI]
+availableUIs = filterM isAvailable [zenityUI, readlineUI]
+
+selectUI :: Bool -> IO UI
+selectUI needgui
+	| needgui = do
+		ok <- isAvailable zenityUI
+		if ok
+			then return zenityUI
+			else error "zenitty is not installed, GUI not available"
+	| otherwise = do
+		l <- availableUIs
+		case l of
+			(u:_) -> return u
+			[] -> error "Neither zenity nor the readline UI are available"