wizards-1.0.2: High level, generic library for interrogative user interfaces

Safe Haskell | Trustworthy
Language | Haskell98

System.Console.Wizard

Contents

- Wizards
- Primitives
- Modifiers
- Convenience
- Utility
- Orphan instances

Synopsis

- newtype Wizard backend a = Wizard (MaybeT (Free backend) a)
- type PromptString = String
- run :: (Functor f, Monad b, Run b f) => Wizard f a -> b (Maybe a)
- class (Functor sub, Functor sup) => sub :<: sup
- data (f :+: g) w
- data Line w
- line :: Line :<: b => PromptString -> Wizard b String
- data LinePrewritten w
- linePrewritten :: LinePrewritten :<: b => PromptString -> String -> String -> Wizard b String
- data Password w
- password :: Password :<: b => PromptString -> Maybe Char -> Wizard b String
- data Character w
- character :: Character :<: b => PromptString -> Wizard b Char
- data Output w
- output :: Output :<: b => String -> Wizard b ()
- data OutputLn w
- outputLn :: OutputLn :<: b => String -> Wizard b ()
- data ArbitraryIO w
- retry :: Functor b => Wizard b a -> Wizard b a
- retryMsg :: OutputLn :<: b => String -> Wizard b a -> Wizard b a
- defaultTo :: Functor b => Wizard b a -> a -> Wizard b a
- parser :: Functor b => (a -> Maybe c) -> Wizard b a -> Wizard b c
- validator :: Functor b => (a -> Bool) -> Wizard b a -> Wizard b a
- nonEmpty :: Functor b => Wizard b [a] -> Wizard b [a]
- inRange :: (Ord a, Functor b) => (a, a) -> Wizard b a -> Wizard b a
- parseRead :: (Read a, Functor b) => Wizard b String -> Wizard b a
- liftMaybe :: Functor b => Maybe a -> Wizard b a
- ensure :: (a -> Bool) -> a -> Maybe a
- readP :: Read a => String -> Maybe a

# Wizards

newtype Wizard backend a #

A `Wizard b a` is a conversation with the user via back-end `b` that will result in a data type `a`, or may fail. A `Wizard` is made up of one or more "primitives" (see below), composed using the `Applicative`, `Monad` and `Alternative` instances. The `Alternative` instance is, as you might expect, a maybe-style cascade. If the first wizard fails, the next one is tried. `mzero` can be used to induce failure directly.

The `Wizard` constructor is exported here for use when developing backends, but it is better for end-users to simply pretend that `Wizard` is an opaque data type. Don't depend on this unless you have no other choice.

`Wizard`s are, internally, just a maybe transformer over a free monad built from some coproduct of functors, each of which is a primitive action.

Constructors

Wizard (MaybeT (Free backend) a) |

Instances

Functor backend => Monad (Wizard backend) # |
Methods (>>=) :: Wizard backend a -> (a -> Wizard backend b) -> Wizard backend b # (>>) :: Wizard backend a -> Wizard backend b -> Wizard backend b # return :: a -> Wizard backend a # fail :: String -> Wizard backend a #
Functor backend => Functor (Wizard backend) # |
Methods fmap :: (a -> b) -> Wizard backend a -> Wizard backend b # (<$) :: a -> Wizard backend b -> Wizard backend a #
Functor backend => Applicative (Wizard backend) # |
Methods pure :: a -> Wizard backend a # (<*>) :: Wizard backend (a -> b) -> Wizard backend a -> Wizard backend b # (*>) :: Wizard backend a -> Wizard backend b -> Wizard backend b # (<*) :: Wizard backend a -> Wizard backend b -> Wizard backend a #
Functor backend => Alternative (Wizard backend) # |
Methods empty :: Wizard backend a # (<|>) :: Wizard backend a -> Wizard backend a -> Wizard backend a # some :: Wizard backend a -> Wizard backend [a] # many :: Wizard backend a -> Wizard backend [a] #
Functor backend => MonadPlus (Wizard backend) # |
Methods mzero :: Wizard backend a # mplus :: Wizard backend a -> Wizard backend a -> Wizard backend a #

type PromptString = String #

A string for a prompt

run :: (Functor f, Monad b, Run b f) => Wizard f a -> b (Maybe a) #

Run a wizard using some back-end.

class (Functor sub, Functor sup) => sub :<: sup #

Subsumption of two functors. You shouldn't define any of your own instances of this when writing back-ends, rely only on GeneralizedNewtypeDeriving.

Minimal complete definition

inj

Instances

Functor f => f :<: f # |
Methods inj :: f a -> f a
ArbitraryIO :<: BasicIO # |
Methods inj :: ArbitraryIO a -> BasicIO a
ArbitraryIO :<: Haskeline # |
Methods inj :: ArbitraryIO a -> Haskeline a
Password :<: Haskeline # |
Methods inj :: Password a -> Haskeline a
LinePrewritten :<: Haskeline # |
Methods inj :: LinePrewritten a -> Haskeline a
Character :<: BasicIO # |
Methods inj :: Character a -> BasicIO a
Character :<: Haskeline # |
Methods inj :: Character a -> Haskeline a
Character :<: Pure # |
Methods inj :: Character a -> Pure a
Line :<: BasicIO # |
Methods inj :: Line a -> BasicIO a
Line :<: Haskeline # |
Methods inj :: Line a -> Haskeline a
Line :<: Pure # |
Methods inj :: Line a -> Pure a
OutputLn :<: BasicIO # |
Methods inj :: OutputLn a -> BasicIO a
OutputLn :<: Haskeline # |
Methods inj :: OutputLn a -> Haskeline a
OutputLn :<: Pure # |
Methods inj :: OutputLn a -> Pure a
Output :<: BasicIO # |
Methods inj :: Output a -> BasicIO a
Output :<: Haskeline # |
Methods inj :: Output a -> Haskeline a
Output :<: Pure # |
Methods inj :: Output a -> Pure a
WithSettings :<: Haskeline # |
Methods inj :: WithSettings a -> Haskeline a
(Functor f, Functor g, Functor h, (:<:) f g) => f :<: ((:+:) h g) # |
Methods inj :: f a -> (h :+: g) a
(Functor f, Functor g) => f :<: ((:+:) f g) # |
Methods inj :: f a -> (f :+: g) a

data (f :+: g) w infixr 9 #

Coproduct of two functors

Instances

(Run b f, Run b g) => Run b ((:+:) f g) # |
Methods runAlgebra :: (f :+: g) (b v) -> b v #
(Functor f, Functor g, Functor h, (:<:) f g) => f :<: ((:+:) h g) # |
Methods inj :: f a -> (h :+: g) a
(Functor f, Functor g) => f :<: ((:+:) f g) # |
Methods inj :: f a -> (f :+: g) a
(Functor g, Functor f) => Functor ((:+:) f g) # |
Methods fmap :: (a -> b) -> (f :+: g) a -> (f :+: g) b # (<$) :: a -> (f :+: g) b -> (f :+: g) a #

# Primitives

Primitives are the basic building blocks for `wizards`. Use these functions to produce wizards that ask for input from the user, or output information.

data Line w #

Instances

Functor Line # |
Methods fmap :: (a -> b) -> Line a -> Line b # (<$) :: a -> Line b -> Line a #
Line :<: BasicIO # |
Methods inj :: Line a -> BasicIO a
Line :<: Haskeline # |
Methods inj :: Line a -> Haskeline a
Line :<: Pure # |
Methods inj :: Line a -> Pure a

line :: Line :<: b => PromptString -> Wizard b String #

Read one line of input from the user. Cannot fail (but may throw exceptions, depending on the backend).

data LinePrewritten w #

Instances

Functor LinePrewritten # |
Methods fmap :: (a -> b) -> LinePrewritten a -> LinePrewritten b # (<$) :: a -> LinePrewritten b -> LinePrewritten a #
LinePrewritten :<: Haskeline # |
Methods inj :: LinePrewritten a -> Haskeline a

linePrewritten #

Arguments

:: LinePrewritten :<: b |
=> PromptString |
-> String | Text to the left of the cursor
-> String | Text to the right of the cursor
-> Wizard b String |

Read one line of input, with some default text already present, before and/or after the editing cursor.

data Password w #

Instances

Functor Password # |
Methods fmap :: (a -> b) -> Password a -> Password b # (<$) :: a -> Password b -> Password a #
Password :<: Haskeline # |
Methods inj :: Password a -> Haskeline a

password #

Arguments

:: Password :<: b |
=> PromptString |
-> Maybe Char | Mask character, if any.
-> Wizard b String |

Read one line of password input, with an optional mask character.

data Character w #

Instances

Functor Character # |
Methods fmap :: (a -> b) -> Character a -> Character b # (<$) :: a -> Character b -> Character a #
Character :<: BasicIO # |
Methods inj :: Character a -> BasicIO a
Character :<: Haskeline # |
Methods inj :: Character a -> Haskeline a
Character :<: Pure # |
Methods inj :: Character a -> Pure a

character :: Character :<: b => PromptString -> Wizard b Char #

Read a single character only from input. Cannot fail (but may throw exceptions, depending on the backend).

data Output w #

Instances

Functor Output # |
Methods fmap :: (a -> b) -> Output a -> Output b # (<$) :: a -> Output b -> Output a #
Output :<: BasicIO # |
Methods inj :: Output a -> BasicIO a
Output :<: Haskeline # |
Methods inj :: Output a -> Haskeline a
Output :<: Pure # |
Methods inj :: Output a -> Pure a

output :: Output :<: b => String -> Wizard b () #

Output a string. Does not fail.

data OutputLn w #

Instances

Functor OutputLn # |
Methods fmap :: (a -> b) -> OutputLn a -> OutputLn b # (<$) :: a -> OutputLn b -> OutputLn a #
OutputLn :<: BasicIO # |
Methods inj :: OutputLn a -> BasicIO a
OutputLn :<: Haskeline # |
Methods inj :: OutputLn a -> Haskeline a
OutputLn :<: Pure # |
Methods inj :: OutputLn a -> Pure a

outputLn :: OutputLn :<: b => String -> Wizard b () #

Output a string followed by a newline. Does not fail.

data ArbitraryIO w #

Instances

Functor ArbitraryIO # |
Methods fmap :: (a -> b) -> ArbitraryIO a -> ArbitraryIO b # (<$) :: a -> ArbitraryIO b -> ArbitraryIO a #
ArbitraryIO :<: BasicIO # |
Methods inj :: ArbitraryIO a -> BasicIO a
ArbitraryIO :<: Haskeline # |
Methods inj :: ArbitraryIO a -> Haskeline a

# Modifiers

Modifiers change the behaviour of existing wizards.

retry :: Functor b => Wizard b a -> Wizard b a #

Retry produces a wizard that will retry the entire conversation again if it fails. It is simply `retry x = x <|> retry x`.

retryMsg :: OutputLn :<: b => String -> Wizard b a -> Wizard b a #

Same as `retry`, except an error message can be specified.

defaultTo :: Functor b => Wizard b a -> a -> Wizard b a #

`x `defaultTo` y` will return `y` if `x` fails, e.g `parseRead line `defaultTo` 0`.

parser :: Functor b => (a -> Maybe c) -> Wizard b a -> Wizard b c #

Like `fmap`, except the function may be partial (`Nothing` causes the wizard to fail).

validator :: Functor b => (a -> Bool) -> Wizard b a -> Wizard b a #

`validator p` causes a wizard to fail if the output value does not satisfy the predicate `p`.

# Convenience

nonEmpty :: Functor b => Wizard b [a] -> Wizard b [a] #

Simply `validator (not . null)`, makes a wizard fail if it gets an empty string.

inRange :: (Ord a, Functor b) => (a, a) -> Wizard b a -> Wizard b a #

Makes a wizard fail if it gets an ordered quantity outside of the given range.

parseRead :: (Read a, Functor b) => Wizard b String -> Wizard b a #

Simply `parser readP`. Attaches a simple `read` parser to a `Wizard`.

# Utility

liftMaybe :: Functor b => Maybe a -> Wizard b a #

Translate a maybe value into wizard success/failure.

ensure :: (a -> Bool) -> a -> Maybe a #

Ensures that a maybe value satisfies a given predicate.

readP :: Read a => String -> Maybe a #

A read-based parser for the `parser` modifier.

# Orphan instances

(:<:) ArbitraryIO b => MonadIO (Wizard b) # |
Methods liftIO :: IO a -> Wizard b a #