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

3 files changed, 167 insertions, 4 deletions

diff --git a/users/grfn/xanthous/src/Xanthous/Generators/Speech.hs b/users/grfn/xanthous/src/Xanthous/Generators/Speech.hs
new file mode 100644
index 000000000000..76830c4d9116
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Generators/Speech.hs
@@ -0,0 +1,108 @@
+{-# LANGUAGE TemplateHaskell #-}
+--------------------------------------------------------------------------------
+module Xanthous.Generators.Speech
+  ( -- * Abstract phonotactics
+    Phonotactics(..)
+    -- ** Lenses
+  , onsets
+  , nuclei
+  , codas
+  , numOnsets
+  , numNuclei
+  , numCodas
+
+    -- ** Definitions for languages
+  , english
+
+    -- * Language generation
+  , syllable
+
+  ) where
+--------------------------------------------------------------------------------
+import           Xanthous.Prelude hiding (replicateM)
+import           Data.Interval (Interval)
+import qualified Data.Interval as Interval
+import           Control.Monad.Random.Class (MonadRandom)
+import           Xanthous.Random (chooseRange, choose, ChooseElement (ChooseElement))
+import           Control.Monad (replicateM)
+--------------------------------------------------------------------------------
+
+newtype Phoneme = Phoneme Text
+  deriving stock (Show, Eq, Generic)
+  deriving anyclass (NFData)
+  deriving newtype (IsString, Semigroup, Monoid)
+
+data Phonotactics = Phonotactics
+  { _onsets    :: [Phoneme]
+  , _nuclei    :: [Phoneme]
+  , _codas     :: [Phoneme]
+  , _numOnsets :: Interval Word
+  , _numNuclei :: Interval Word
+  , _numCodas  :: Interval Word
+  }
+  deriving stock (Show, Eq, Generic)
+  deriving anyclass (NFData)
+makeLenses ''Phonotactics
+
+syllable :: MonadRandom m => Phonotactics -> m Text
+syllable phonotactics = do
+  let genPart num choices = do
+        n <- fromIntegral . fromMaybe 0 <$> chooseRange (phonotactics ^. num)
+        fmap (fromMaybe mempty . mconcat)
+          . replicateM n
+          . choose . ChooseElement
+          $ phonotactics ^. choices
+
+  (Phoneme onset) <- genPart numOnsets onsets
+  (Phoneme nucleus) <- genPart numNuclei nuclei
+  (Phoneme coda) <- genPart numCodas codas
+
+  pure $ onset <> nucleus <> coda
+
+--------------------------------------------------------------------------------
+
+-- <https://en.wikipedia.org/wiki/English_phonology#Phonotactics>
+english :: Phonotactics
+english = Phonotactics
+  { _onsets = [ "pl" , "bl" , "kl" , "gl" , "pr" , "br" , "tr" , "dr" , "kr"
+              , "gr" , "tw" , "dw" , "gw" , "kw" , "pw"
+
+              , "fl" , "sl" , {- "thl", -} "shl" {- , "vl" -}
+              , "p", "b", "t", "d", "k", "ɡ", "m", "n", "f", "v", "th", "s"
+              , "z", "h", "l", "w"
+
+              , "sp", "st", "sk"
+
+              , "sm", "sn"
+
+              , "sf", "sθ"
+
+              , "spl", "skl", "spr", "str", "skr", "skw", "sm", "sp", "st", "sk"
+              ]
+  , _nuclei = [ "a", "e", "i", "o", "u", "ur", "ar", "or", "ear", "are", "ure"
+              , "oa", "ee", "oo", "ei", "ie", "oi", "ou"
+              ]
+  , _codas = [ "m", "n", "ng", "p", "t", "tsh", "k", "f", "sh", "s", "th", "x"
+             , "v", "z", "zh", "l", "r", "w"
+
+             , "lk", "lb", "lt", "ld", "ltsh", "ldsh", "lk"
+             , "rp", "rb", "rt", "rd", "rtsh", "rdsh", "rk", "rɡ"
+             , "lf", "lv", "lth", "ls", "lz", "lsh", "lth"
+             , "rf", "rv", "rth", "rs", "rz", "rth"
+             , "lm", "ln"
+             , "rm", "rn", "rl"
+             , "mp", "nt", "nd", "nth", "nsh", "ŋk"
+             , "mf", "ms", "mth", "nf", "nth", "ns", "nz", "ŋθ"
+             , "ft", "sp", "st", "sk"
+             , "fth"
+             , "pt", "kt"
+             , "pth", "ps", "th", "ts", "dth", "dz", "ks"
+             , "lpt", "lps", "lfth", "lts", "lst", "lkt", "lks"
+             , "rmth", "rpt", "rps", "rts", "rst", "rkt"
+             , "mpt", "mps", "ndth", "ŋkt", "ŋks", "ŋkth"
+             , "ksth", "kst"
+             ]
+  , _numOnsets = Interval.singleton 1
+  , _numNuclei = Interval.singleton 1
+  , _numCodas  = Interval.singleton 1
+  }
diff --git a/users/grfn/xanthous/src/Xanthous/Orphans.hs b/users/grfn/xanthous/src/Xanthous/Orphans.hs
index 1fe9708edbe0..2a9a7a7ebc29 100644
--- a/users/grfn/xanthous/src/Xanthous/Orphans.hs
+++ b/users/grfn/xanthous/src/Xanthous/Orphans.hs
@@ -1,10 +1,10 @@
 {-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE StandaloneDeriving #-}
 {-# LANGUAGE UndecidableInstances #-}
-{-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE PackageImports #-}
 {-# OPTIONS_GHC -Wno-orphans #-}
 --------------------------------------------------------------------------------
+{-# OPTIONS_GHC -Wno-deferred-type-errors #-}
 module Xanthous.Orphans
   ( ppTemplate
   ) where
@@ -31,6 +31,8 @@ import           Linear
 --------------------------------------------------------------------------------
 import           Xanthous.Util.JSON
 import           Xanthous.Util.QuickCheck
+import qualified Data.Interval as Interval
+import Data.Interval (Interval, Extended (..))
 --------------------------------------------------------------------------------
 
 instance forall s a.
@@ -350,3 +352,23 @@ deriving newtype instance (Arbitrary s, CoArbitrary (m (a, s)))
 deriving via (GenericArbitrary (V2 a)) instance Arbitrary a => Arbitrary (V2 a)
 instance CoArbitrary a => CoArbitrary (V2 a)
 instance Function a => Function (V2 a)
+
+--------------------------------------------------------------------------------
+
+instance Arbitrary r => Arbitrary (Extended r) where
+  arbitrary = oneof [ pure NegInf
+                    , pure PosInf
+                    , Finite <$> arbitrary
+                    ]
+
+instance Arbitrary Interval.Boundary where
+  arbitrary = elements [ Interval.Open , Interval.Closed ]
+
+instance (Ord r, Arbitrary r) => Arbitrary (Interval r) where
+  arbitrary = do
+    lower <- arbitrary
+    upper <- arbitrary
+    pure $ (if upper < lower then flip else id)
+      Interval.interval
+      lower
+      upper
diff --git a/users/grfn/xanthous/src/Xanthous/Random.hs b/users/grfn/xanthous/src/Xanthous/Random.hs
index 6d34109df7f8..d97dcb9e1175 100644
--- a/users/grfn/xanthous/src/Xanthous/Random.hs
+++ b/users/grfn/xanthous/src/Xanthous/Random.hs
@@ -11,9 +11,10 @@ module Xanthous.Random
   , subRand
   , chance
   , chooseSubset
+  , chooseRange
   ) where
 --------------------------------------------------------------------------------
-import Xanthous.Prelude
+import           Xanthous.Prelude
 --------------------------------------------------------------------------------
 import           Data.List.NonEmpty (NonEmpty(..))
 import           Control.Monad.Random.Class (MonadRandom(getRandomR, getRandom))
@@ -25,6 +26,9 @@ import           Data.Random.Distribution.Uniform
 import           Data.Random.Distribution.Uniform.Exclusive
 import           Data.Random.Sample
 import qualified Data.Random.Source as DRS
+import           Data.Interval ( Interval, lowerBound', Extended (Finite)
+                               , upperBound', Boundary (Closed)
+                               )
 --------------------------------------------------------------------------------
 
 instance {-# INCOHERENT #-} (Monad m, MonadRandom m) => DRS.MonadRandom m where
@@ -81,11 +85,13 @@ evenlyWeighted = Weighted . itoList
 weightedBy :: Functor t => (a -> w) -> t a -> Weighted w t a
 weightedBy weighting xs = Weighted $ (weighting &&& id) <$> xs
 
-instance (Num w, Ord w, Distribution Uniform w, Excludable w) => Choose (Weighted w [] a) where
+instance (Num w, Ord w, Distribution Uniform w, Excludable w)
+       => Choose (Weighted w [] a) where
   type RandomResult (Weighted w [] a) = Maybe a
   choose (Weighted ws) = sample $ headMay <$> weightedSample 1 ws
 
-instance (Num w, Ord w, Distribution Uniform w, Excludable w) => Choose (Weighted w NonEmpty a) where
+instance (Num w, Ord w, Distribution Uniform w, Excludable w)
+       => Choose (Weighted w NonEmpty a) where
   type RandomResult (Weighted w NonEmpty a) = a
   choose (Weighted ws) =
     sample
@@ -112,6 +118,33 @@ chooseSubset :: ( Num w, Ord w, Distribution Uniform w, Excludable w
                ) => w -> t a -> m (t a)
 chooseSubset = filterA . const . chance
 
+-- | Choose a random @n@ in the given interval
+chooseRange
+  :: ( MonadRandom m
+    , Distribution Uniform n
+    , Enum n
+    , Bounded n, Show n, Ord n)
+  => Interval n
+  -> m (Maybe n)
+chooseRange int = traverse sample distribution
+  where
+    (lower, lowerBoundary) = lowerBound' int
+    lowerR = case lower of
+      Finite x -> if lowerBoundary == Closed
+                 then x
+                 else succ x
+      _ -> minBound
+    (upper, upperBoundary) = upperBound' int
+    upperR = case upper of
+      Finite x -> if upperBoundary == Closed
+                 then x
+                 else pred x
+      _ -> maxBound
+    distribution
+      | lowerR <= upperR = Just $ Uniform lowerR upperR
+      | otherwise = Nothing
+
+
 --------------------------------------------------------------------------------
 
 bools :: NonEmpty Bool