Database.Bolt.Extras.DSL

Selectors for nodes, relations and paths

These data types let you specify Cypher queries.

With OverloadedLabels and operators you can write selectors in very concise Cypher-like form:

(#n .: "Name" .# ["name" =: "C42"]) -: (defR .: "NAME_OF") :!->: (#m .: "Molecule")
(n:Name{name:"C42"})-[:NAME_OF]->(m:Molecule)

data NodeSelector

Selector for Nodes.

This datatype has OverloadedLabels instance to simplify specifying nodes. Labels produce empty nodes.

#foo :: NodeSelector
-- foo = NodeSelector (Just "foo") [] []

Constructors

NodeSelector

Fields

• nodeIdentifier :: Maybe Text
• nodeLabels :: [Text]
• nodeProperties :: [(Text, Value)]
• nodeParams :: [(Text, Text)]

Instances

Show NodeSelector

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

showsPrec :: Int -> NodeSelector -> ShowS

show :: NodeSelector -> String

showList :: [NodeSelector] -> ShowS

Eq NodeSelector

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

(==) :: NodeSelector -> NodeSelector -> Bool

(/=) :: NodeSelector -> NodeSelector -> Bool

SelectorLike NodeSelector

Defined in Database.Bolt.Extras.DSL.Internal.Instances

Methods

withIdentifier :: Text -> NodeSelector -> NodeSelector

withLabel :: Text -> NodeSelector -> NodeSelector

withProp :: (Text, Value) -> NodeSelector -> NodeSelector

withParam :: (Text, Text) -> NodeSelector -> NodeSelector

ToCypher NodeSelector

Defined in Database.Bolt.Extras.DSL.Internal.Instances

Methods

toCypher :: NodeSelector -> Text

KnownSymbol x => IsLabel x NodeSelector

Defined in Database.Bolt.Extras.DSL.Internal.Instances

Methods

fromLabel :: NodeSelector

data RelSelector

Selector for URelationships.

This datatype has OverloadedLabels instance as well, similar to NodeSelector.

Constructors

RelSelector

Fields

• relIdentifier :: Maybe Text
• relLabel :: Text
• relProperties :: [(Text, Value)]
• relParams :: [(Text, Text)]

Instances

Show RelSelector

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

showsPrec :: Int -> RelSelector -> ShowS

show :: RelSelector -> String

showList :: [RelSelector] -> ShowS

Eq RelSelector

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

(==) :: RelSelector -> RelSelector -> Bool

(/=) :: RelSelector -> RelSelector -> Bool

SelectorLike RelSelector

Defined in Database.Bolt.Extras.DSL.Internal.Instances

Methods

withIdentifier :: Text -> RelSelector -> RelSelector

withLabel :: Text -> RelSelector -> RelSelector

withProp :: (Text, Value) -> RelSelector -> RelSelector

withParam :: (Text, Text) -> RelSelector -> RelSelector

ToCypher RelSelector

Defined in Database.Bolt.Extras.DSL.Internal.Instances

Methods

toCypher :: RelSelector -> Text

KnownSymbol x => IsLabel x RelSelector

Defined in Database.Bolt.Extras.DSL.Internal.Instances

Methods

fromLabel :: RelSelector

class SelectorLike a where

Class for Selectors, which can update identifier, labels and props.

Methods

withIdentifier :: Text -> a -> a

withLabel :: Text -> a -> a

withProp :: (Text, Value) -> a -> a

withParam :: (Text, Text) -> a -> a

Instances

SelectorLike NodeSelector

Defined in Database.Bolt.Extras.DSL.Internal.Instances

Methods

withIdentifier :: Text -> NodeSelector -> NodeSelector

withLabel :: Text -> NodeSelector -> NodeSelector

withProp :: (Text, Value) -> NodeSelector -> NodeSelector

withParam :: (Text, Text) -> NodeSelector -> NodeSelector

SelectorLike RelSelector

Defined in Database.Bolt.Extras.DSL.Internal.Instances

Methods

withIdentifier :: Text -> RelSelector -> RelSelector

withLabel :: Text -> RelSelector -> RelSelector

withProp :: (Text, Value) -> RelSelector -> RelSelector

withParam :: (Text, Text) -> RelSelector -> RelSelector

(.:) :: SelectorLike a => a -> Text -> a infixl 9

Operator version of withLabel. To be used with OverloadedLabels instances.

#foo .: "Foo" :: NodeSelector

(.#) :: SelectorLike a => a -> [(Text, Value)] -> a infixl 9

Operator version of withProp. To be used with OverloadedLabels instances.

See also =: from Database.Bolt package.

#foo .# ["bar" =: 42, "baz" =: "baz"] :: NodeSelector

toNodeSelector :: HasCallStack => Node -> NodeSelector

toRelSelector :: HasCallStack => URelationship -> RelSelector

data PathSelector

Constructors

PathSelector :-!: PathPart infixl 1

not directed relation

PathSelector :<-!: PathPart infixl 1

directed relation

P NodeSelector

starting node of Path

Instances

Show PathSelector

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

showsPrec :: Int -> PathSelector -> ShowS

show :: PathSelector -> String

showList :: [PathSelector] -> ShowS

Eq PathSelector

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

(==) :: PathSelector -> PathSelector -> Bool

(/=) :: PathSelector -> PathSelector -> Bool

ToCypher PathSelector

Defined in Database.Bolt.Extras.DSL.Internal.Instances

Methods

toCypher :: PathSelector -> Text

data PathPart

Selector for paths.

Constructors

RelSelector :!->: NodeSelector infixl 2

directed relation

RelSelector :!-: NodeSelector infixl 2

not directed relation

Instances

Show PathPart

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

showsPrec :: Int -> PathPart -> ShowS

show :: PathPart -> String

showList :: [PathPart] -> ShowS

Eq PathPart

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

(==) :: PathPart -> PathPart -> Bool

(/=) :: PathPart -> PathPart -> Bool

(-:) :: NodeSelector -> PathPart -> PathSelector infixl 1

Combined version of :-!: and P for specifying the first node of path.

(<-:) :: NodeSelector -> PathPart -> PathSelector infixl 1

Combined version of :<-!: and P for specifying the first node of path.

data Selector

Constructors

PS PathSelector

path selector

TS Text

free text selector

Instances

Show Selector

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

showsPrec :: Int -> Selector -> ShowS

show :: Selector -> String

showList :: [Selector] -> ShowS

Eq Selector

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

(==) :: Selector -> Selector -> Bool

(/=) :: Selector -> Selector -> Bool

ToCypher Selector

Defined in Database.Bolt.Extras.DSL.Internal.Instances

Methods

toCypher :: Selector -> Text

ToCypher Selectors

Defined in Database.Bolt.Extras.DSL.Internal.Instances

Methods

toCypher :: Selectors -> Text

type Selectors = [Selector]

(#) :: a -> (a -> b) -> b

Default selectors

defaultNode :: NodeSelector

Empty NodeSelector.

defN :: NodeSelector

Shorter synonym for defaultRel.

defaultRel :: RelSelector

Empty RelSelector.

defR :: RelSelector

Shorter synonym for defaultRel.

Cypher conditions

data Cond

Conditions.

Constructors

ID Text BoltId

ID(txt) = boltId

IDs Text [BoltId]

ID(txt) IN [boltId1, boltId2, ... ]

IN Text [Text]

txt IN [txt1, txt2, ... ]

TC Text

free text condition

Instances

Show Cond

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

showsPrec :: Int -> Cond -> ShowS

show :: Cond -> String

showList :: [Cond] -> ShowS

Eq Cond

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

(==) :: Cond -> Cond -> Bool

(/=) :: Cond -> Cond -> Bool

ToCypher Cond

Defined in Database.Bolt.Extras.DSL.Internal.Instances

Methods

toCypher :: Cond -> Text

data Conds

Constructors

Conds :&&: Conds infixr 3

condition AND condition

Conds :||: Conds infixr 2

condition OR condition

C Cond

single condition

Not Conds

NOT condition

Instances

Show Conds

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

showsPrec :: Int -> Conds -> ShowS

show :: Conds -> String

showList :: [Conds] -> ShowS

Eq Conds

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

(==) :: Conds -> Conds -> Bool

(/=) :: Conds -> Conds -> Bool

ToCypher Conds

Defined in Database.Bolt.Extras.DSL.Internal.Instances

Methods

toCypher :: Conds -> Text

DSL for Cypher

The free-monadic DSL lets you write Cypher queries in Haskell like this:

formQuery $ do
   matchF [
     PS $ (#n .: "Name" .# ["name" =: "C42"]) -: (defR .: "NAME_OF") :!->: (#m .: "Molecule")
   ]
   returnF ["n", "m"]

DSL operations

type CypherDSL a = Free Expr a

A synonym for Free DSL.

createF :: Selectors -> Free Expr ()

Prepare CREATE query

matchF :: Selectors -> Free Expr ()

Prepare MATCH query

optionalMatchF :: Selectors -> Free Expr ()

Prepare 'OPTIONAL MATCH' query

mergeF :: Selectors -> Free Expr ()

Prepare MERGE query

whereF :: Conds -> Free Expr ()

Prepare WHERE query

setF :: [Text] -> Free Expr ()

Prepare SET query

deleteF :: [Text] -> Free Expr ()

Prepare DELETE query

detachDeleteF :: [Text] -> Free Expr ()

Prepare 'DETACH DELETE' query

removeF :: [Text] -> Free Expr ()

Prepare REMOVE query

returnF :: [Text] -> Free Expr ()

Prepare RETURN query

withF :: [Text] -> Free Expr ()

Prepare WITH query

textF :: Text -> Free Expr ()

Prepare query with custom text

Rendering Cypher queries

formQuery :: Free Expr () -> Text

Implementation details

data Expr next

Expression in Cypher language.

Constructors

Create Selectors next

CREATE query

Match Selectors next

MATCH query

OptionalMatch Selectors next

OPTIONAL MATCH query

Merge Selectors next

MERGE query

Where Conds next

WHERE query

Set [Text] next

SET query

Delete [Text] next

DELETE query

DetachDelete [Text] next

DETACH DELETE query

Remove [Text] next

REMOVE query

Return [Text] next

RETURN query

With [Text] next

WITH query

Text Text next

free text query

Instances

Functor Expr

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

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

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

Show next => Show (Expr next)

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

showsPrec :: Int -> Expr next -> ShowS

show :: Expr next -> String

showList :: [Expr next] -> ShowS

Eq next => Eq (Expr next)

Defined in Database.Bolt.Extras.DSL.Internal.Types

Methods

(==) :: Expr next -> Expr next -> Bool

(/=) :: Expr next -> Expr next -> Bool