Data.Greskell.Binder

Types

data Binder a

A Monad that manages binding variables to values.

>>> let binder = (,) <$> newBind (10 :: Int) <*> newBind "hoge"
>>> let ((var_int, var_str), binding) = runBinder binder
>>> toGremlin var_int
"__v0"
>>> toGremlin var_str
"__v1"
>>> sortBy (comparing fst) $ HashMap.toList binding
[("__v0",Number 10.0),("__v1",String "hoge")]

Instances

Monad Binder

Methods

(>>=) :: Binder a -> (a -> Binder b) -> Binder b

(>>) :: Binder a -> Binder b -> Binder b

return :: a -> Binder a

fail :: String -> Binder a

Functor Binder

Methods

fmap :: (a -> b) -> Binder a -> Binder b

(<$) :: a -> Binder b -> Binder a

Applicative Binder

Methods

pure :: a -> Binder a

(<*>) :: Binder (a -> b) -> Binder a -> Binder b

liftA2 :: (a -> b -> c) -> Binder a -> Binder b -> Binder c

(*>) :: Binder a -> Binder b -> Binder b

(<*) :: Binder a -> Binder b -> Binder a

type Binding = Object

Binding between Gremlin variable names and JSON values.

Actions

newBind

Arguments

:: ToJSON v

=> v

bound value

-> Binder (Greskell v)

variable

Create a new Gremlin variable bound to the given value.

The value v is kept in the monadic context. The returned Greskell is a Gremlin variable pointing to the v. The Gremlin variable is guaranteed to be unique in the current monadic context.

Runners

runBinder :: Binder a -> (a, Binding)

Execute the given Binder monad to obtain Binding.