1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE UndecidableInstances #-}
module Events.Types
( TimeRange(..), rangeStart, rangeDuration
, Event(..), payload, occursWithin
, EvalCtx(..), ctxVars, ctxEvents
, ObjCtx(..), objOccurs, objPayload
, Eval, evaluate
, module Data.Aeson
, module Data.Time.Clock
, module Data.Default.Class
) where
import Control.Lens.TH
import Data.Aeson (Object)
import Data.Time.Clock
import Control.Monad.State.Lazy
import ListT (ListT)
import qualified ListT
import Data.Default.Class
import Data.Monoid
import Control.Monad.Fix
import Control.Lens
import Data.Maybe
import Debug.Trace
data TimeRange = TimeRange
{ _rangeStart :: UTCTime
, _rangeDuration :: NominalDiffTime
}
makeLenses ''TimeRange
data Event = Event
{ _payload :: Object
, _occursWithin :: TimeRange -> Bool
}
makeLenses ''Event
data EvalCtx = EvalCtx
{ _ctxVars :: Object
, _ctxEvents :: [Object]
} deriving (Show)
makeLenses ''EvalCtx
instance Default EvalCtx where
def = EvalCtx
{ _ctxVars = mempty
, _ctxEvents = mempty
}
data ObjCtx = ObjCtx
{ _objOccurs :: Bool
, _objPayload :: Maybe Object
}
makeLenses ''ObjCtx
instance Default ObjCtx where
def = ObjCtx
{ _objOccurs = False
, _objPayload = Nothing
}
objCtx :: ObjCtx -> Maybe Object
objCtx (ObjCtx False _) = Nothing
objCtx (ObjCtx True o) = o
type Eval m a = StateT ObjCtx (ListT (StateT EvalCtx m)) a
evaluate :: MonadFix m => Eval m () -> m [Object]
evaluate x = catMaybes <$> mfix x'
where
x' = evalStateT (ListT.toList (objCtx <$> execStateT x def)) . flip (set ctxEvents) def . catMaybes
instance MonadState s m => MonadState s (ListT m) where
get = lift get
put = lift . put
|
