Stackctl.OneOrListOf

Documentation

data OneOrListOf a

Type representing one a or a list of a

This type is isomorphic both NonEmpty a and Either a [a]. Its primary use-case is to parse Yaml (through its FromJSON) where users may specify a list of values, but specifying a single value is worth supporting, typically for backwards-compatibility:

something:
  field:
    - one
    - two

something:
  field: one # => should be treated like field: [one]

The Foldable instance should be used to treat the value like a list, such as extracting it directly via toList.

Implementation note: this type preserves the form in which it was decoded (in other words, it's not a newtype over one of the isomorphic types mentioned above), so that we can encode it back out in the same format.

Instances

Foldable OneOrListOf

Defined in Stackctl.OneOrListOf

Methods

fold :: Monoid m => OneOrListOf m -> m

foldMap :: Monoid m => (a -> m) -> OneOrListOf a -> m

foldMap' :: Monoid m => (a -> m) -> OneOrListOf a -> m

foldr :: (a -> b -> b) -> b -> OneOrListOf a -> b

foldr' :: (a -> b -> b) -> b -> OneOrListOf a -> b

foldl :: (b -> a -> b) -> b -> OneOrListOf a -> b

foldl' :: (b -> a -> b) -> b -> OneOrListOf a -> b

foldr1 :: (a -> a -> a) -> OneOrListOf a -> a

foldl1 :: (a -> a -> a) -> OneOrListOf a -> a

toList :: OneOrListOf a -> [a]

null :: OneOrListOf a -> Bool

length :: OneOrListOf a -> Int

elem :: Eq a => a -> OneOrListOf a -> Bool

maximum :: Ord a => OneOrListOf a -> a

minimum :: Ord a => OneOrListOf a -> a

sum :: Num a => OneOrListOf a -> a

product :: Num a => OneOrListOf a -> a

FromJSON a => FromJSON (OneOrListOf a)

Defined in Stackctl.OneOrListOf

Methods

parseJSON :: Value -> Parser (OneOrListOf a)

parseJSONList :: Value -> Parser [OneOrListOf a]

ToJSON a => ToJSON (OneOrListOf a)

Defined in Stackctl.OneOrListOf

Methods

toJSON :: OneOrListOf a -> Value

toEncoding :: OneOrListOf a -> Encoding

toJSONList :: [OneOrListOf a] -> Value

toEncodingList :: [OneOrListOf a] -> Encoding

Semigroup (OneOrListOf a)

Defined in Stackctl.OneOrListOf

Methods

(<>) :: OneOrListOf a -> OneOrListOf a -> OneOrListOf a

sconcat :: NonEmpty (OneOrListOf a) -> OneOrListOf a

stimes :: Integral b => b -> OneOrListOf a -> OneOrListOf a

Generic (OneOrListOf a)

Defined in Stackctl.OneOrListOf

Associated Types

type Rep (OneOrListOf a) :: Type -> Type

Methods

from :: OneOrListOf a -> Rep (OneOrListOf a) x

to :: Rep (OneOrListOf a) x -> OneOrListOf a

Show a => Show (OneOrListOf a)

Defined in Stackctl.OneOrListOf

Methods

showsPrec :: Int -> OneOrListOf a -> ShowS

show :: OneOrListOf a -> String

showList :: [OneOrListOf a] -> ShowS

Eq a => Eq (OneOrListOf a)

Defined in Stackctl.OneOrListOf

Methods

(==) :: OneOrListOf a -> OneOrListOf a -> Bool

(/=) :: OneOrListOf a -> OneOrListOf a -> Bool

type Rep (OneOrListOf a)

Defined in Stackctl.OneOrListOf

type Rep (OneOrListOf a) = D1 ('MetaData "OneOrListOf" "Stackctl.OneOrListOf" "stackctl-1.5.0.0-61wZOBL41ScJGzzlVG4mIH" 'False) (C1 ('MetaCons "One" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)) :+: C1 ('MetaCons "List" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 [a])))

fromList :: [a] -> OneOrListOf a