diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,10 @@
 # Changelog for hasklepias
 
+## 0.13.0
+
+* Adds a rudimentary `Attributes` type and `HasAttributes` typeclass for adding attributes to `Feature`s. This interfaces will likely change in the future, but for now users have the ability to add information like labels to a `Feature`. In fact, `Feature`s which are encoded to JSON are *required* to have attributes.
+* Adds rudimentary `Stype` module in order to (ultimately) interface with the [R `stype` package](https://docs.novisci.com/stype/). For now, this module simply creates a few of the types, some of which are *not* an appropriate implementation. For example, the `Nominal` type is simply `newtype Nominal a = Nominal a`. Essentially, it's just a way to label something as nominal at this point.
+
 ## 0.12.0
 
 * Converts `AttritionStatus` from a List to a NonEmpty container.
diff --git a/exampleApp/Main.hs b/exampleApp/Main.hs
--- a/exampleApp/Main.hs
+++ b/exampleApp/Main.hs
@@ -12,6 +12,7 @@
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
 module Main(
   main
 ) where
@@ -36,6 +37,9 @@
    ( Feature "allEvents" (Events Day)
    -> Feature "dummy" Status)
 critTrue = define $ pure Include 
+
+instance HasAttributes "dummy" Bool where
+  getAttributes _ = MkAttributes "Text" "Text" "Text"
 
 {-------------------------------------------------------------------------------
   Cohort Specifications and evaluation
diff --git a/examples/ExampleCohort1.hs b/examples/ExampleCohort1.hs
--- a/examples/ExampleCohort1.hs
+++ b/examples/ExampleCohort1.hs
@@ -8,10 +8,11 @@
 
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE NoImplicitPrelude #-}
-{-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
 module ExampleCohort1(
   exampleCohort1tests
 ) where
@@ -65,17 +66,18 @@
 -------------------------------------------------------------------------------}
 
 -- | Defines a feature that returns 'True' ('False' otherwise) if either:
---   * at least 1 event during the baseline interval has any of the 'c1' concepts
---   * there are at least 2 event that have 'c2' concepts which have at least
+--   * at least 1 event during the baseline interval has any of the 'cpts1' concepts
+--   * there are at least 2 event that have 'cpts2' concepts which have at least
 --     7 days between them during the baseline interval
 twoOutOneIn ::
-       [Text]
-    -> [Text]
+       [Text] -- ^ cpts1
+    -> [Text] -- ^ cpts2
     -> Definition
     ( Feature "calendarIndex" (Index Interval Day)
     -> Feature "allEvents" (Events Day)
     -> Feature name Bool )
-twoOutOneIn cpts1 cpts2 = define
+twoOutOneIn cpts1 cpts2 = 
+  define
     (\index events ->
         atleastNofX 1 cpts1  (getBaselineConcur index events) 
         || ( 
@@ -181,7 +183,6 @@
 critFemale :: Definition
  (   Feature "allEvents" (Events Day)
   -> Feature "isFemale" Status)
-
 critFemale =
     define
       (\events ->
@@ -243,8 +244,6 @@
         --  excludeIf ( maybe False (beforeIndex index) mDeadDay) -- different way to write logic
       )
 
-
-
 {-------------------------------------------------------------------------------
   Covariate features
 -------------------------------------------------------------------------------}
@@ -260,6 +259,14 @@
 
 diabetes :: BoolFeatDef "diabetes"
 diabetes = twoOutOneIn ["is_diabetes_outpatient"] ["is_diabetes_inpatient"]
+
+instance HasAttributes  "diabetes" Bool where
+  getAttributes _ = MkAttributes 
+    "Has Diabetes"
+    "Has Diabetes within baseline"
+    "Has at least 1 event during the baseline interval has any of the 'cpts1' concepts \
+    \ OR there are at least 2 event that have 'cpts2' concepts which have at least 7 days \
+    \ between them during the baseline interval"
 
 ckd :: BoolFeatDef "ckd"
 ckd =  twoOutOneIn ["is_ckd_outpatient"] ["is_ckd_inpatient"]
diff --git a/hasklepias.cabal b/hasklepias.cabal
--- a/hasklepias.cabal
+++ b/hasklepias.cabal
@@ -1,6 +1,6 @@
 cabal-version:  2.2
 name:           hasklepias
-version:        0.12.0
+version:        0.13.0
 description:    Please see the README on GitHub at <https://github.com/novisci/asclepias#readme>
 homepage:       https://github.com/novisci/asclepias/#readme
 bug-reports:    https://github.com/novisci/asclepias/issues
@@ -31,6 +31,7 @@
       EventData.Context.Domain.Demographics
       FeatureCompose
       FeatureCompose.Aeson
+      FeatureCompose.Attributes
       FeatureEvents
       Hasklepias
       Hasklepias.Aeson
@@ -40,6 +41,13 @@
       Hasklepias.Cohort
       Hasklepias.Cohort.Criteria
       Hasklepias.Cohort.Index
+      Stype
+      Stype.Numeric
+      Stype.Numeric.Count
+      Stype.Numeric.Continuous
+      Stype.Numeric.Censored
+      Stype.Categorical
+      Stype.Categorical.Nominal
   other-modules:
       Paths_hasklepias
   autogen-modules:
@@ -59,8 +67,10 @@
     , lens == 5.0.1
     , lens-aeson == 1.1.1
     , mtl == 2.2.2
+    , nonempty-containers == 0.3.4.1
     , process == 1.6.12.0
     , safe >= 0.3
+    , semiring-simple == 1.0.0.1
     , tasty  == 1.4.1
     , tasty-hunit == 0.10.0.3
     , text == 1.2.4.1
diff --git a/src/FeatureCompose.hs b/src/FeatureCompose.hs
--- a/src/FeatureCompose.hs
+++ b/src/FeatureCompose.hs
@@ -33,6 +33,7 @@
   , missingBecause
   , makeFeature
   , getFeatureData
+  , getFData
   , getData
   , getDataN
   , getNameN
@@ -45,6 +46,7 @@
   , Eval
   , eval
 
+  , HasAttributes(..)
 ) where
 
 import safe Control.Applicative        ( Applicative(..)
@@ -62,15 +64,17 @@
 import safe GHC.Generics               ( Generic )
 import safe GHC.Show                   ( Show(show) )
 import safe GHC.TypeLits               ( KnownSymbol, Symbol, symbolVal )
-
+import safe FeatureCompose.Attributes
 {- | 
 Defines the reasons that a @'FeatureData'@ value may be missing. Can be used to
 indicate the reason that a @'Feature'@'s data was unable to be derived or does
 not need to be derived. 
 -}
+{- tag::missingReason[] -}
 data MissingReason =
     InsufficientData -- ^ Insufficient information available to derive data.
   | Other Text -- ^ User provided reason for missingness
+{- end::missingReason[] -}
   deriving (Eq, Show, Generic)
 
 {- | 
@@ -82,9 +86,11 @@
 constructed with @'featureDataL'@ or its synonym @'missingBecause'@.
 
 -}
+{- tag::featureData[] -}
 newtype FeatureData d = MkFeatureData { 
     getFeatureData :: Either MissingReason d  -- ^ Unwrap FeatureData.
   }
+{- end::featureData[] -}
   deriving (Eq, Show, Generic)
 
 -- | Creates a non-missing 'FeatureData'. Since @'FeatureData'@ is an instance of
@@ -165,8 +171,10 @@
 Except when using @'pure'@ to lift data into a @Feature@, @Feature@s can only be
 derived from other @Feature@ via a @'Definition'@.
 -}
+{- tag::feature[] -}
 newtype (KnownSymbol name) => Feature name d =
   MkFeature { getFData :: FeatureData d }
+{- end::feature[] -}
   deriving (Eq)
 
 -- | A utility for constructing a @'Feature'@ from @'FeatureData'@.
@@ -370,3 +378,11 @@
       case liftA3 f x y z of
           MkFeatureData (Left l)  -> MkFeature $ MkFeatureData (Left l)
           MkFeatureData (Right r) -> r
+
+{- | Initializes @Feature@ @Attributes@ to empty strings -}
+
+class HasAttributes n a where
+  getAttributes :: Feature n a -> Attributes
+
+-- instance HasAttributes name d where
+--   getAttributes x = MkAttributes "" "" ""
diff --git a/src/FeatureCompose/Aeson.hs b/src/FeatureCompose/Aeson.hs
--- a/src/FeatureCompose/Aeson.hs
+++ b/src/FeatureCompose/Aeson.hs
@@ -9,6 +9,7 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE FlexibleContexts #-}
 
 module FeatureCompose.Aeson(
 ) where
@@ -19,7 +20,9 @@
                                     , MissingReason
                                     , FeatureData
                                     , getFeatureData
-                                    , getData )
+                                    , getFData
+                                    , HasAttributes(..) )
+import FeatureCompose.Attributes
 import Data.Aeson                   ( object, KeyValue((.=)), ToJSON(toJSON) )
 import Data.Proxy                   ( Proxy(Proxy) )
 
@@ -28,13 +31,19 @@
 
 instance ToJSON MissingReason
 
-instance (ToJSON d)=> ToJSON (FeatureData d) where
+instance (ToJSON d) => ToJSON (FeatureData d) where
     toJSON  x = case getFeatureData x of
       (Left l)  -> toJSON l
       (Right r) -> toJSON r
 
-instance (KnownSymbol n, ToJSON d) => ToJSON (Feature n d) where
-    toJSON x = object [ --"name"   .= getName x
-                         "name"  .= show (symbolVal (Proxy @n))
-                      --  , "attrs" .= toJSON (getAttr x)
-                       , "data"  .= toJSON (getData x) ]
+instance ToJSON Attributes where
+
+-- instance (KnownSymbol n, ToJSON d) => ToJSON (Feature n d) where
+--     toJSON x = object [  "name"  .= show (symbolVal (Proxy @n))
+--                       --  , "attrs" .= toJSON (getAttributes x)
+--                        , "data"  .= toJSON (getFData x) ]
+
+instance (KnownSymbol n, ToJSON d, HasAttributes n d) => ToJSON (Feature n d) where
+    toJSON x = object [  "name"  .= show (symbolVal (Proxy @n))
+                       , "attrs" .= toJSON (getAttributes x)
+                       , "data"  .= toJSON (getFData x) ]
diff --git a/src/FeatureCompose/Attributes.hs b/src/FeatureCompose/Attributes.hs
new file mode 100644
--- /dev/null
+++ b/src/FeatureCompose/Attributes.hs
@@ -0,0 +1,39 @@
+{-|
+Module      : Functions for defining attributes Feature data
+Description : Defines attributes instances for Features.
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+-}
+{-# OPTIONS_HADDOCK hide #-}
+{-# LANGUAGE Safe #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE DeriveGeneric #-}
+
+module FeatureCompose.Attributes(
+    Attributes(..)
+  -- , HasAttributes(..)
+) where
+
+import safe Data.Eq         ( Eq )
+import safe Data.Text       ( Text )
+import safe GHC.Show        ( Show )
+import safe GHC.Generics    ( Generic )
+
+{- |
+A data type for holding attritbutes of Features. This type and the @HasAttributes@
+are likely to change in future versions.
+-}
+data Attributes = MkAttributes { 
+    getShortLabel :: Text
+  , getLongLabel :: Text
+  , getDerivation :: Text
+  } deriving (Eq, Show, Generic)
+
+-- class HasAttributes a where
+--   getAttributes :: a -> Attributes
+
+
diff --git a/src/Hasklepias.hs b/src/Hasklepias.hs
--- a/src/Hasklepias.hs
+++ b/src/Hasklepias.hs
@@ -21,6 +21,8 @@
     , module EventData.Arbitrary
     
     , module FeatureCompose
+    -- ** Adding Attributes to Features
+    , module FeatureCompose.Attributes
     -- ** Writing Features to JSON
     , module FeatureCompose.Aeson
 
@@ -41,6 +43,9 @@
     -- ** Creating an executable cohort application
     , module Hasklepias.MakeApp
 
+    -- * Statistical Types
+    , module Stype
+
     -- * Rexported Functions and modules
     , module Hasklepias.Reexports
     , module Hasklepias.ReexportsUnsafe
@@ -58,6 +63,7 @@
 
 import FeatureCompose
 import FeatureCompose.Aeson
+import FeatureCompose.Attributes
 import FeatureEvents
 import Hasklepias.Reexports
 import Hasklepias.ReexportsUnsafe
@@ -65,3 +71,5 @@
 import Hasklepias.Cohort.Criteria
 import Hasklepias.Aeson
 import Hasklepias.MakeApp
+
+import Stype
diff --git a/src/Stype.hs b/src/Stype.hs
new file mode 100644
--- /dev/null
+++ b/src/Stype.hs
@@ -0,0 +1,19 @@
+{-|
+Module      : Stype 
+Description : Statistical types
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+
+-}
+
+{-# OPTIONS_HADDOCK hide #-}
+-- {-# LANGUAGE Safe #-}
+
+module Stype (
+    module Stype.Numeric
+  , module Stype.Categorical
+) where 
+
+import Stype.Numeric
+import Stype.Categorical
diff --git a/src/Stype/Categorical.hs b/src/Stype/Categorical.hs
new file mode 100644
--- /dev/null
+++ b/src/Stype/Categorical.hs
@@ -0,0 +1,14 @@
+{-|
+Module      : Stype categorical
+Description : Statistical types
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+
+-}
+-- {-# LANGUAGE Safe #-}
+module Stype.Categorical (
+  module Stype.Categorical.Nominal 
+) where
+
+import Stype.Categorical.Nominal
diff --git a/src/Stype/Categorical/Nominal.hs b/src/Stype/Categorical/Nominal.hs
new file mode 100644
--- /dev/null
+++ b/src/Stype/Categorical/Nominal.hs
@@ -0,0 +1,17 @@
+{-|
+Module      : Stype categorical
+Description : Statistical types
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+
+-}
+-- {-# LANGUAGE Safe #-}
+module Stype.Categorical.Nominal (
+  Nomimal(..)
+) where
+
+-- import qualified Data.Set.NonEmpty as NES
+
+{- | a placeholder for a future nominal type -}
+newtype Nomimal a = Nomimal a deriving ( Eq, Show, Ord )
diff --git a/src/Stype/Numeric.hs b/src/Stype/Numeric.hs
new file mode 100644
--- /dev/null
+++ b/src/Stype/Numeric.hs
@@ -0,0 +1,26 @@
+{-|
+Module      : Stype numeric types
+Description : Statistical types
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+
+-}
+
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE Safe #-}
+
+module Stype.Numeric (
+    module Stype.Numeric.Count
+  , module Stype.Numeric.Continuous
+  , module Stype.Numeric.Censored
+) where
+
+import safe Stype.Numeric.Count
+import safe Stype.Numeric.Continuous
+import safe Stype.Numeric.Censored
+
+instance Censorable Double where
+instance (Ord a) => Censorable (EventTime a) where
diff --git a/src/Stype/Numeric/Censored.hs b/src/Stype/Numeric/Censored.hs
new file mode 100644
--- /dev/null
+++ b/src/Stype/Numeric/Censored.hs
@@ -0,0 +1,43 @@
+{-|
+Module      : Stype censored types and typeclasses
+Description : Statistical types
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+
+-}
+
+{-# LANGUAGE Safe #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module Stype.Numeric.Censored (
+    Censorable(..)
+  , MaybeCensored(..)
+) where
+
+import safe Data.Text                    (Text)
+
+data MaybeCensored a where
+  IntervalCensored :: a -> a -> MaybeCensored a
+  RightCensored :: a -> MaybeCensored a
+  LeftCensored :: a -> MaybeCensored a
+  Uncensored :: a -> MaybeCensored a
+  deriving( Eq, Show, Ord )
+
+class (Ord a) => Censorable a where
+
+  parseIntervalCensor :: a -> a -> Either Text (MaybeCensored a)
+  parseIntervalCensor x y 
+    | x < y = Right $ IntervalCensored x y
+    | otherwise = Left "y >= x"
+
+  rightCensor ::  a -> a -> MaybeCensored a
+  rightCensor c t
+    | c < t     = RightCensored c 
+    | otherwise = Uncensored t
+
+  leftCensor ::  a -> a -> MaybeCensored a
+  leftCensor c t
+    | c >= t    = LeftCensored c
+    | otherwise = Uncensored t
diff --git a/src/Stype/Numeric/Continuous.hs b/src/Stype/Numeric/Continuous.hs
new file mode 100644
--- /dev/null
+++ b/src/Stype/Numeric/Continuous.hs
@@ -0,0 +1,53 @@
+{-|
+Module      : Stype continuous types
+Description : Statistical types
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+
+-}
+
+{-# LANGUAGE Safe #-}
+module Stype.Numeric.Continuous (
+    Continuous(..)
+  , NonnegContinuous(..)
+  , EventTime(..)
+  , mkEventTime
+) where
+
+import safe Control.Applicative           ( Applicative(liftA2) )
+
+
+data Continuous a = NegContInf | Cont a | ContInf
+  deriving (Eq, Show, Ord)
+
+instance Functor Continuous where
+  fmap f (Cont x) = Cont (f x)
+  fmap f NegContInf = NegContInf
+  fmap f ContInf = ContInf
+
+instance Applicative Continuous where
+  pure x = Cont x
+  (<*>) (Cont f) (Cont x) =  Cont (f x)
+  (<*>) NegContInf (Cont x) =  NegContInf
+  (<*>) ContInf (Cont x) =  ContInf
+  (<*>) _ NegContInf =  NegContInf
+  (<*>) _ ContInf =  ContInf
+
+instance Num a => Num (Continuous a) where
+  (+) = liftA2 (+)
+  (*) = liftA2 (*) 
+  abs = fmap abs
+  fromInteger x = Cont $ fromInteger x
+  signum = fmap signum
+  negate = fmap negate
+
+data NonnegContinuous a = NonNeg a | NonNegInf
+  deriving (Eq, Show, Ord)
+
+newtype EventTime a = EventTime { getEventTime :: NonnegContinuous a }
+  deriving (Eq, Show, Ord)
+
+mkEventTime :: Maybe a -> EventTime a
+mkEventTime (Just x) = EventTime $ NonNeg x
+mkEventTime Nothing  = EventTime NonNegInf
diff --git a/src/Stype/Numeric/Count.hs b/src/Stype/Numeric/Count.hs
new file mode 100644
--- /dev/null
+++ b/src/Stype/Numeric/Count.hs
@@ -0,0 +1,49 @@
+{-|
+Module      : Stype count
+Description : Statistical types
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+
+-}
+
+{-# LANGUAGE Safe #-}
+
+module Stype.Numeric.Count (
+  Count(..)
+) where
+
+import safe GHC.Num                      ( Natural )
+import safe Data.Semiring                ( Semiring(..) )
+
+newtype Count = Count Natural
+  deriving (Eq, Show, Ord)
+
+instance Num Count where
+  (+) (Count x) (Count y) = Count (x + y)
+  (*) (Count x) (Count y) = Count (x * y) 
+  fromInteger x = Count $ fromInteger x
+  abs = id -- useless
+  signum x = Count 1 -- useless
+  negate = id -- useless
+
+instance Semigroup Natural where
+  (<>) x y = x + y
+
+instance Monoid Natural where
+  mempty = 0
+
+instance Semiring Natural where
+  one = 1
+  (<.>) = (*)
+
+instance Semigroup Count where
+  (<>) (Count x) (Count y) = Count (x <> y)
+
+instance Monoid Count where
+  mempty = Count 0
+
+instance Semiring Count where
+  one = Count 1
+  (<.>) = (*)
+
diff --git a/test/FeatureCompose/AesonSpec.hs b/test/FeatureCompose/AesonSpec.hs
--- a/test/FeatureCompose/AesonSpec.hs
+++ b/test/FeatureCompose/AesonSpec.hs
@@ -1,5 +1,8 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
 module FeatureCompose.AesonSpec (spec) where
 
 import IntervalAlgebra
@@ -8,6 +11,7 @@
 import FeatureEvents
 import FeatureCompose
 import FeatureCompose.Aeson
+import FeatureCompose.Attributes
 import Data.Aeson (encode)
 import Data.Maybe
 import Data.Time as DT
@@ -27,10 +31,23 @@
         Nothing -> featureDataL (Other "No Enrollment")
         Just x  -> pure (getInterval x)
 
+dummy ::  Feature "dummy" Bool
+dummy = pure True
 
+instance HasAttributes "dummy" Bool where
+    getAttributes x = MkAttributes "some Label" "longer label..." "a description"
+
+
 spec :: Spec
 spec = do
     it "an Int event is parsed correctly" $
        encode (index ex1)  `shouldBe` "{\"end\":10,\"begin\":0}"
+
+    it "dummy encodes correctly" $
+        encode dummy `shouldBe` 
+        "{\"data\":true,\"name\":\"\\\"dummy\\\"\",\
+        \\"attrs\":{\"getDerivation\":\"a description\",\
+        \\"getLongLabel\":\"longer label...\",\
+        \\"getShortLabel\":\"some Label\"}}"
 
 
diff --git a/test/FeatureComposeSpec.hs b/test/FeatureComposeSpec.hs
--- a/test/FeatureComposeSpec.hs
+++ b/test/FeatureComposeSpec.hs
@@ -66,6 +66,32 @@
 f3F = define f3
 
 
+featInts :: [Int] -> Feature "someInts" [Int]
+featInts = pure
+
+feat1 :: Definition (Feature "someInts" [Int] -> Feature "hasMoreThan3" Bool)
+feat1 = defineA
+  (\ints -> if null ints then makeFeature (missingBecause $ Other "no data")
+           else makeFeature $ featureDataR (length ints > 3))
+
+feat2 :: Definition (
+      Feature "hasMoreThan3" Bool
+  -> Feature "someInts" [Int]
+  -> Feature "sum" Int)
+feat2 = define (\b ints -> if b then sum ints else 0)
+
+ex0 = featInts []
+ex0a = eval feat1 ex0 -- MkFeature (MkFeatureData (Left (Other "no data")))
+ex0b = eval feat2 (ex0a, ex0) -- MkFeature (MkFeatureData (Left (Other "no data")))
+
+ex1 = featInts [3, 8]
+ex1a = eval feat1 ex1 -- MkFeature (MkFeatureData (Right False))
+ex1b = eval feat2 (ex1a, ex1) -- MkFeature (MkFeatureData (Right 0))
+
+ex2 = featInts [1..4]
+ex2a = eval feat1 ex2 -- MkFeature (MkFeatureData (Right True))
+ex2b = eval feat2 (ex2a, ex2) -- MkFeature (MkFeatureData (Right 10))
+
 spec :: Spec
 spec = do
 
@@ -131,3 +157,12 @@
         eval f3F (pure True, eval f2F (pure False)) `shouldBe` makeFeature (missingBecause (Other "test"))
       it "eval of f3F  returns correct value" $
         eval f3F (pure True, eval f2F (pure True)) `shouldBe` pure "this"
+
+  describe "checking ex0-2" $
+    do
+      it "ex0b" $
+        ex0b `shouldBe` makeFeature (missingBecause (Other "no data"))
+      it "ex1b" $
+        ex1b `shouldBe` makeFeature (featureDataR 0)
+      it "ex2b" $
+        ex2b `shouldBe` makeFeature (featureDataR 10)