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semantic/semantic-core/test/Generators.hs
2019-07-22 14:24:40 -04:00

58 lines
1.5 KiB
Haskell

{-# LANGUAGE ScopedTypeVariables #-}
module Generators
( literal
, name
, variable
, boolean
, lambda
, apply
, ifthenelse
) where
import Prelude hiding (span)
import Hedgehog hiding (Var)
import qualified Hedgehog.Gen as Gen
import qualified Hedgehog.Range as Range
import Data.Core
import Data.Name
import Data.Term
-- The 'prune' call here ensures that we don't spend all our time just generating
-- fresh names for variables, since the length of variable names is not an
-- interesting property as they parse regardless.
name :: MonadGen m => m (Named User)
name = Gen.prune ((Named . Ignored <*> id) <$> names) where
names = Gen.text (Range.linear 1 10) Gen.lower
boolean :: MonadGen m => m (Term Core User)
boolean = bool <$> Gen.bool
variable :: MonadGen m => m (Term Core User)
variable = pure . namedValue <$> name
ifthenelse :: MonadGen m => m (Term Core User) -> m (Term Core User)
ifthenelse bod = Gen.subterm3 boolean bod bod if'
apply :: MonadGen m => m (Term Core User) -> m (Term Core User)
apply gen = go where
go = Gen.recursive
Gen.choice
[ Gen.subterm2 gen gen ($$)]
[ Gen.subterm2 go go ($$) -- balanced
, Gen.subtermM go (\x -> lam <$> name <*> pure x)
]
lambda :: MonadGen m => m (Term Core User) -> m (Term Core User)
lambda bod = do
arg <- name
Gen.subterm bod (lam arg)
atoms :: MonadGen m => [m (Term Core User)]
atoms = [boolean, variable, pure unit]
literal :: MonadGen m => m (Term Core User)
literal = Gen.recursive Gen.choice atoms [lambda literal]