Env

This implements the model environments that users must provide upon running a model; such environments assign traces of values to the "observable variables" (random variables which can be conditioned against) of a model.

Observable variable

data ObsVar (x :: Symbol) where

Containers for observable variables

Constructors

ObsVar :: KnownSymbol x => ObsVar x

Instances

(KnownSymbol x, x ~ x') => IsLabel x (ObsVar x')

Allows the syntax #x to be automatically lifted to the type ObsVar "x".

Defined in Env

Methods

fromLabel :: ObsVar x'

varToStr :: forall x. ObsVar x -> String

Convert an observable variable from a type-level string to a value-level string

Model environment

data Assign x a

Assign or associate a variable x with a value of type a

Constructors

x := a

Instances

FindElem x2 env => FindElem (x2 :: k) ((x' := a2) ': env :: [Assign x1 a1])

Defined in Env

Methods

findElem :: Idx x2 ((x' := a2) ': env)

FindElem (x2 :: x1) ((x2 := a2) ': env :: [Assign x1 a1])

Defined in Env

Methods

findElem :: Idx x2 ((x2 := a2) ': env)

(KnownSymbol x, Show a, Show (Env env)) => Show (Env ((x := a) ': env))

Defined in Env

Methods

showsPrec :: Int -> Env ((x := a) ': env) -> ShowS

show :: Env ((x := a) ': env) -> String

showList :: [Env ((x := a) ': env)] -> ShowS

Show (Env ('[] :: [Assign Symbol Type]))

Defined in Env

Methods

showsPrec :: Int -> Env '[] -> ShowS

show :: Env '[] -> String

showList :: [Env '[]] -> ShowS

FromSTrace ('[] :: [Assign Symbol Type])

Defined in Trace

Methods

fromSTrace :: STrace -> Env '[]

(UniqueKey x env ~ 'True, KnownSymbol x, Eq a, Member a PrimVal, FromSTrace env) => FromSTrace ((x := a) ': env)

Defined in Trace

Methods

fromSTrace :: STrace -> Env ((x := a) ': env)

data Env (env :: [Assign Symbol *]) where

A model environment assigning traces (lists) of observed values to observable variables i.e. the type Env ((x := a) : env) indicates x is assigned a value of type [a].

Constructors

ENil :: Env '[]

ECons :: [a] -> Env env -> Env ((x := a) ': env)

Instances

(KnownSymbol x, Show a, Show (Env env)) => Show (Env ((x := a) ': env))

Defined in Env

Methods

showsPrec :: Int -> Env ((x := a) ': env) -> ShowS

show :: Env ((x := a) ': env) -> String

showList :: [Env ((x := a) ': env)] -> ShowS

Show (Env ('[] :: [Assign Symbol Type]))

Defined in Env

Methods

showsPrec :: Int -> Env '[] -> ShowS

show :: Env '[] -> String

showList :: [Env '[]] -> ShowS

(<:>) :: UniqueKey x env ~ True => Assign (ObsVar x) [a] -> Env env -> Env ((x := a) ': env) infixr 5

Prepend a variable assignment to a model environment

nil :: Env '[]

Empty model environment

class (FindElem x env, LookupType x env ~ a) => Observable env x a where

Specifies that an environment Env env has an observable variable x whose observed values are of type a

Methods

get :: ObsVar x -> Env env -> [a]

set :: ObsVar x -> [a] -> Env env -> Env env

Instances

(FindElem x env, LookupType x env ~ a) => Observable env x a

Defined in Env

Methods

get :: ObsVar x -> Env env -> [a]

set :: ObsVar x -> [a] -> Env env -> Env env

type family Observables env (ks :: [Symbol]) a :: Constraint where ...

For each observable variable x in xs, construct the constraint Observable env x a

Equations

Observables env (x ': xs) a = (Observable env x a, Observables env xs a)

Observables env '[] a = ()

type family UniqueKey x env where ...

Check whether an observable variable x is unique in model environment env

Equations

UniqueKey x ((x := a) ': env) = False

UniqueKey x ((x' := a) ': env) = UniqueKey x env

UniqueKey x '[] = True

type family LookupType x env where ...

Retrieve the type of an observable variable x from an environment env

Equations

LookupType x ((x := a) ': env) = a

LookupType x ((x' := a) ': env) = LookupType x env