Safe Haskell	None
Language	Haskell2010

Database.PostgreSQL.LTree

Description

This module provides types and functions for PostgreSQL's ltree https://www.postgresql.org/docs/current/ltree.html

You will want to use a specific implementation, e.g. postgresql-simple-ltree.

Synopsis

newtype LTree = LTree {
- unLTree :: Seq Label
}
data Label
map :: (Label -> Label) -> LTree -> LTree
fromList :: [Label] -> LTree
toList :: LTree -> [Label]
rootLabel :: LTree -> Maybe Label
parentLabel :: LTree -> Maybe Label
parent :: LTree -> Maybe LTree
numLabels :: LTree -> Int
mkLabel :: Text -> Either String Label
unsafeMkLabel :: Text -> Label
uuidToLabel :: UUID -> Label
empty :: LTree
null :: LTree -> Bool
singleton :: Label -> LTree
snoc :: LTree -> Label -> LTree
render :: LTree -> Text
unsafeUncheckedParse :: Text -> LTree
parse :: Text -> Either String LTree
isImmediateParentOf :: LTree -> LTree -> Bool
isImmediateChildOf :: LTree -> LTree -> Bool
parseUUIDFromLabel :: Label -> Either String UUID
allLabelsUnique :: LTree -> Bool

Documentation

newtype LTree Source #

Wrapper for Postgres' ltree (label tree) type.

Constructors

LTree
Fields unLTree :: Seq Label

Instances

Instances details

Eq LTree Source #
Instance details Defined in Database.PostgreSQL.LTree Methods (==) :: LTree -> LTree -> Bool # (/=) :: LTree -> LTree -> Bool #
Ord LTree Source #
Instance details Defined in Database.PostgreSQL.LTree Methods compare :: LTree -> LTree -> Ordering # (<) :: LTree -> LTree -> Bool # (<=) :: LTree -> LTree -> Bool # (>) :: LTree -> LTree -> Bool # (>=) :: LTree -> LTree -> Bool # max :: LTree -> LTree -> LTree # min :: LTree -> LTree -> LTree #
Show LTree Source #
Instance details Defined in Database.PostgreSQL.LTree Methods showsPrec :: Int -> LTree -> ShowS # show :: LTree -> String # showList :: [LTree] -> ShowS #
ToJSON LTree Source #
Instance details Defined in Database.PostgreSQL.LTree Methods toJSON :: LTree -> Value # toEncoding :: LTree -> Encoding # toJSONList :: [LTree] -> Value # toEncodingList :: [LTree] -> Encoding #
FromJSON LTree Source #
Instance details Defined in Database.PostgreSQL.LTree Methods parseJSON :: Value -> Parser LTree # parseJSONList :: Value -> Parser [LTree] #

data Label Source #

Wrapper for a single label in an ltree. The constructor IS NOT exported to ensure we only construct valid labels. See mkLabel for constructing a Label.

Instances

Instances details

Eq Label Source #
Instance details Defined in Database.PostgreSQL.LTree Methods (==) :: Label -> Label -> Bool # (/=) :: Label -> Label -> Bool #
Ord Label Source #
Instance details Defined in Database.PostgreSQL.LTree Methods compare :: Label -> Label -> Ordering # (<) :: Label -> Label -> Bool # (<=) :: Label -> Label -> Bool # (>) :: Label -> Label -> Bool # (>=) :: Label -> Label -> Bool # max :: Label -> Label -> Label # min :: Label -> Label -> Label #
Show Label Source #
Instance details Defined in Database.PostgreSQL.LTree Methods showsPrec :: Int -> Label -> ShowS # show :: Label -> String # showList :: [Label] -> ShowS #
ToJSON Label Source #
Instance details Defined in Database.PostgreSQL.LTree Methods toJSON :: Label -> Value # toEncoding :: Label -> Encoding # toJSONList :: [Label] -> Value # toEncodingList :: [Label] -> Encoding #
FromJSON Label Source #
Instance details Defined in Database.PostgreSQL.LTree Methods parseJSON :: Value -> Parser Label # parseJSONList :: Value -> Parser [Label] #

map :: (Label -> Label) -> LTree -> LTree Source #

Produce a new LTree by applying the supplied function to each Label.

fromList :: [Label] -> LTree Source #

Convert a list to an LTree.

toList :: LTree -> [Label] Source #

Convert an LTree to a list.

rootLabel :: LTree -> Maybe Label Source #

Get the first Label from an LTree if one exists.

parentLabel :: LTree -> Maybe Label Source #

Get the second-to-last Label in an LTree.

parent :: LTree -> Maybe LTree Source #

Get the parent path of an LTree.

numLabels :: LTree -> Int Source #

Get the length of an LTree.

mkLabel :: Text -> Either String Label Source #

Safely construct a Label from Text. If the supplied Text contains characters unsupported by ltree. On failure, returns Left with an error message.

unsafeMkLabel :: Text -> Label Source #

Same as mkLabel except throws an error for an invalid Text input.

uuidToLabel :: UUID -> Label Source #

A UUID can always be converted into a Label without error by dropping the hyphens. The resulting Label will only contain numbers and lower-case alpha characters.

empty :: LTree Source #

An empty LTree.

null :: LTree -> Bool Source #

Test whether an LTree is empty.

singleton :: Label -> LTree Source #

Construct an LTree from a single Label.

snoc :: LTree -> Label -> LTree Source #

Append a single Label to the end of an LTree; should be O(1) since it's delegating to |>

render :: LTree -> Text Source #

Render an ltree as it would appear in the database.

unsafeUncheckedParse :: Text -> LTree Source #

Unsafely parse an LTree from Text assuming each Label is valid. Use this only if you sure the input is a valid LTree; e.g. it was fetched from a field the database of type ltree.

parse :: Text -> Either String LTree Source #

Parse an LTree from Text. If any Label present is invalid, returns Left.

isImmediateParentOf :: LTree -> LTree -> Bool Source #

Test whether the first LTree is an immediate parent of the second; e.g. a.b is an immediate parent of a.b.c

isImmediateChildOf :: LTree -> LTree -> Bool Source #

Test whether the first LTree is an immediate child of the second; e.g. a.b.c is an immediate child of a.b

parseUUIDFromLabel :: Label -> Either String UUID Source #

Attempt to parse a UUID from a Label.

allLabelsUnique :: LTree -> Bool Source #

Test whether all labels in the LTree are unique.