feat(xanthous): Add a generator for random english syllables r/2656

Add a new "speech" generator module, with the beginnings of the vague
definition of the phonotactics of the language (there's one in here for
English based on the wikipedia article for English phonology, but it's
less than ideal as it has generated words like "sprurlkt") and the
ability to generate random syllables of a language by picking an onset,
nucleus, and coda from the list for that language (within a range of the
number of allowed of each syllable part). This will be used down the
road to automatically generate utterances from various
non-english-speaking creatures (so the accuracy is less important, just
that it "feels real").

Change-Id: I7b81375ec595239c05c5c800cbde1a2a900e38ac
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3202
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI

1 files changed, 21 insertions, 1 deletions

diff --git a/users/grfn/xanthous/test/Xanthous/RandomSpec.hs b/users/grfn/xanthous/test/Xanthous/RandomSpec.hs
index 187336f08650..c88bd9562928 100644
--- a/users/grfn/xanthous/test/Xanthous/RandomSpec.hs
+++ b/users/grfn/xanthous/test/Xanthous/RandomSpec.hs
@@ -5,7 +5,10 @@ import Test.Prelude
 --------------------------------------------------------------------------------
 import Control.Monad.Random
 --------------------------------------------------------------------------------
-import Xanthous.Random
+import           Xanthous.Random
+import           Xanthous.Orphans ()
+import qualified Data.Interval as Interval
+import           Data.Interval (Interval, Extended (Finite), (<=..<=))
 --------------------------------------------------------------------------------
 
 main :: IO ()
@@ -18,6 +21,23 @@ test = testGroup "Xanthous.Random"
       $ \(l :: [Int]) (Positive (r :: Double)) -> randomTest $ do
         ss <- chooseSubset r l
         pure $ all (`elem` l) ss
+    ]
+  , testGroup "chooseRange"
+    [ testProperty "chooses in the range"
+      $ \(rng :: Interval Int) ->
+        not (Interval.null rng)
+        ==> randomTest ( do
+                chooseRange rng >>= \case
+                  Just r -> pure
+                           . counterexample (show r)
+                           $ r `Interval.member` rng
+                  Nothing -> pure $ property Discard
+            )
+    , testProperty "nonEmpty range is never empty"
+      $ \ (lower :: Int) (NonZero diff) -> randomTest $ do
+        let upper = lower + diff
+        r <- chooseRange (Finite lower <=..<= Finite upper)
+        pure $ isJust r
 
     ]
   ]