Generalize periodToHz

changelog/2023-03-01T10_02_55+01_00_generalized_periodToHz

@@ -0,0 +1 @@
+Changed: Generalized `periodToHz`. Use type applications (`periodToHz @Natural @(Ratio Natural)`) to get the old behaviour back, in case type errors arise.

clash-prelude/src/Clash/Signal/Internal.hs

@@ -2,7 +2,7 @@
 Copyright  :  (C) 2013-2016, University of Twente,
                   2017-2019, Myrtle Software Ltd
                   2017-2022, Google Inc.,
-                  2021-2022, QBayLogic B.V.
+                  2021-2023, QBayLogic B.V.
 License    :  BSD2 (see the file LICENSE)
 Maintainer :  QBayLogic B.V. <devops@qbaylogic.com>
 -}
@@ -195,6 +195,8 @@ import Clash.XException
 >>> import Clash.Signal.Internal
 >>> import Clash.Promoted.Nat
 >>> import Clash.XException
+>>> import Data.Ratio (Ratio)
+>>> import Numeric.Natural (Natural)
 >>> type System = "System"
 >>> let systemClockGen = clockGen @System
 >>> let systemResetGen = resetGen @System
@@ -1617,11 +1619,19 @@ hzToFs freq = Femtoseconds (floor ((1.0 / freq) / 1.0e-15))
 -- i.e. to calculate the clock frequency of a clock with a period of 5000 ps:
 --
 -- >>> periodToHz 5000
+-- 2.0e8
+--
+-- To get the old behaviour of this function, use type applications:
+--
+-- >>> periodToHz @Natural @(Ratio Natural) 5000
 -- 200000000 % 1
 --
 -- __NB__: This function is /not/ synthesizable
-periodToHz :: Natural -> Ratio Natural
-periodToHz period = 1.0 / (1.0e-12 * fromIntegral period)
+periodToHz :: (Integral a, Fractional b) => a -> b
+periodToHz = fromRational . toRational . periodToHzx
+ where
+  periodToHzx :: Integral a => a -> Ratio Natural
+  periodToHzx period = 1.0 / (1.0e-12 * fromIntegral period)
 
 -- | Calculate the frequence in __Hz__, given the period in __fs__
 --