xmonad-config/lib/ACPI.hs

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2020-03-13 20:50:13 -04:00
module ACPI (ACPIEvent(..), acpiMagic, isDischarging) where
import Control.Exception
import Text.Read
data ACPIEvent = Power | Sleep | LidClose deriving (Eq)
instance Show ACPIEvent where
show Power = "power"
show Sleep = "sleep"
-- show LidOpen = "olid"
show LidClose = "clid"
instance Read ACPIEvent where
readPrec = do
Ident s <- lexP
case s of
-- TODO this isn't DRY
"power" -> return Power
"sleep" -> return Sleep
"clid" -> return LidClose
_ -> pfail
-- TODO use a data type that enforces strings of max length 5
acpiMagic :: String
acpiMagic = "%acpi"
isDischarging :: IO (Maybe Bool)
isDischarging = do
status <- try $ readFile "/sys/class/power_supply/BAT0/status"
:: IO (Either IOException String)
case status of
Left e -> do
print e
return Nothing
Right s -> return $ Just (s == "Discharging")