oneOf -package:split

Randomly uses one of the given generators. The input list must be non-empty.

oneOf cs succeeds if the current character is in the supplied list of characters cs. Returns the parsed character. See also satisfy.

vowel  = oneOf "aeiou"

oneOf ts succeeds if the current token is in the supplied collection of tokens ts. Returns the parsed token. Note that this parser cannot automatically generate the “expected” component of error message, so usually you should label it manually with label or (<?>).

oneOf cs = satisfy (`elem` cs)

See also: satisfy.

digit = oneOf ['0'..'9'] <?> "digit"

Performance note: prefer satisfy when you can because it's faster when you have only a couple of tokens to compare to:

quoteFast = satisfy (\x -> x == '\'' || x == '\"')
quoteSlow = oneOf "'\""

oneOf cs succeeds if the current character is in the supplied list of characters cs. Returns the parsed character. See also satisfy.

vowel  = oneOf "aeiou"

Parse the first alternative in the list that succeeds.

Match any one of the given characters

>>> match (oneOf "1a") "1"
"1"

>>> match (oneOf "2a") "1"
""

Nondeterministically choose an element from a Foldable collection. This can be used to emulate the style of nondeterminism associated with programming in the list monad:

pythagoreanTriples = do
a <- oneOf [1..10]
b <- oneOf [1..10]
c <- oneOf [1..10]
guard (a^2 + b^2 == c^2)
pure (a, b, c)

Match any one of the elements in the supplied list.

>>> oneOf xs = Parser.satisfy (`Foldable.elem` xs)

When performance matters a pattern matching predicate could be more efficient than a Foldable datatype:

let p x =
case x of
a -> True
e -> True
_  -> False
in satisfy p

GHC may use a binary search instead of linear search in the list. Alternatively, you can also use an array instead of list for storage and search.

Helper to define a character class.

>>> prove $ \(c :: SChar) -> c `match` oneOf "ABCD" .<=> sAny (c .==) (map literal "ABCD")
Q.E.D.

Randomly uses one of the given generators. The input structure must be non-empty.

λ> import qualified Faker.Address as FA
λ> let fakes = [FA.country, FA.postcode, FA.state]
λ> generate (oneof fakes)
Montana

Get any element of a list with equal probability.

Randomly uses one of the given generators. The input list must be non-empty.

Generate a value with one of many generators Uniformly selects a generator and shrinks towards the first one.

oneOf cs succeeds if the current character is in the supplied list of characters cs. Returns the parsed character.

Select one of the provided alternatives given a number.

Call inputlist() on the neovim side and ask the user for a choice. This function returns Nothing if the user input was invalid or Just the chosen element. The elements are rendered via Pretty.

oneOf cs succeeds if the current character is in the supplied list of characters cs. Returns the parsed character. See also satisfy.

vowel  = oneOf "aeiou"

Randomly uses one of the given generators. The input list must be non-empty.