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

Safe HaskellTrustworthy
LanguageHaskell98

System.Console.Wizard

Contents

Synopsis

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.

Wizards 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).

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

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 #