Ditto.Core

This module defines the Form type, its instances, core manipulation functions, and a bunch of helper utilities.

Proved

data Proved a

Proved records a value, the location that value came from, and something that was proved about the value.

Constructors

Proved

Fields

• pos :: FormRange
• unProved :: a

Instances

Functor Proved

Defined in Ditto.Core

Methods

fmap :: (a -> b) -> Proved a -> Proved b

(<$) :: a -> Proved b -> Proved a

Show a => Show (Proved a)

Defined in Ditto.Core

Methods

showsPrec :: Int -> Proved a -> ShowS

show :: Proved a -> String

showList :: [Proved a] -> ShowS

unitProved :: FormId -> Proved ()

Utility Function: trivially prove nothing about ()

FormState

type FormState m input = ReaderT (Environment m input) (StateT FormRange m)

inner state used by Form.

data Value a

used to represent whether a value was found in the form submission data, missing from the form submission data, or expected that the default value should be used

Constructors

Default

Missing

Found a

getFormInput :: Monad m => FormState m input (Value input)

Utility function: Get the current input

getFormInput' :: Monad m => FormId -> FormState m input (Value input)

Utility function: Gets the input of an arbitrary FormId.

getFormRange :: Monad m => FormState m i FormRange

Utility function: Get the current range

data Environment m input

The environment is where you get the actual input per form.

The NoEnvironment constructor is typically used when generating a view for a GET request, where no data has yet been submitted. This will cause the input elements to use their supplied default values.

Note that NoEnviroment is different than supplying an empty environment.

Constructors

Environment (FormId -> m (Value input))

NoEnvironment

Instances

(Semigroup input, Monad m) => Semigroup (Environment m input)

Defined in Ditto.Core

Methods

(<>) :: Environment m input -> Environment m input -> Environment m input

sconcat :: NonEmpty (Environment m input) -> Environment m input

stimes :: Integral b => b -> Environment m input -> Environment m input

(Semigroup input, Monad m) => Monoid (Environment m input)

Not quite sure when this is useful and so hard to say if the rules for combining things with Missing/Default are correct

Defined in Ditto.Core

Methods

mempty :: Environment m input

mappend :: Environment m input -> Environment m input -> Environment m input

mconcat :: [Environment m input] -> Environment m input

getFormId :: Monad m => FormState m i FormId

Utility function: returns the current FormId. This will only make sense if the form is not composed

getNamedFormId :: Monad m => String -> FormState m i FormId

incFormId :: Monad m => FormState m i ()

Utility function: increment the current FormId.

newtype View err v

A view represents a visual representation of a form. It is composed of a function which takes a list of all errors and then produces a new view

Constructors

View

Fields

• unView :: [(FormRange, err)] -> v

Instances

Functor (View err)

Defined in Ditto.Core

Methods

fmap :: (a -> b) -> View err a -> View err b

(<$) :: a -> View err b -> View err a

Semigroup v => Semigroup (View err v)

Defined in Ditto.Core

Methods

(<>) :: View err v -> View err v -> View err v

sconcat :: NonEmpty (View err v) -> View err v

stimes :: Integral b => b -> View err v -> View err v

Monoid v => Monoid (View err v)

Defined in Ditto.Core

Methods

mempty :: View err v

mappend :: View err v -> View err v -> View err v

mconcat :: [View err v] -> View err v

Form

newtype Form m input err view a

a Form contains a View combined with a validation function which will attempt to extract a value from submitted form data.

It is highly parameterized, allowing it work in a wide variety of different configurations. You will likely want to make a type alias that is specific to your application to make type signatures more manageable.

m

A monad which can be used by the validator

input

A framework specific type for representing the raw key/value pairs from the form data

err

A application specific type for err messages

view

The type of data being generated for the view (HSP, Blaze Html, Heist, etc)

proof

A type which names what has been proved about the pure value. () means nothing has been proved.

a

Value pure by form when it is successfully decoded, validated, etc.

This type is very similar to the Form type from digestive-functors <= 0.2. If proof is (), then Form is an applicative functor and can be used almost exactly like digestive-functors <= 0.2.

Constructors

Form

Fields

• unForm :: FormState m input (View err view, m (Result err (Proved a)))

Instances

Functor m => Bifunctor (Form m input err)

Defined in Ditto.Core

Methods

bimap :: (a -> b) -> (c -> d) -> Form m input err a c -> Form m input err b d

first :: (a -> b) -> Form m input err a c -> Form m input err b c

second :: (b -> c) -> Form m input err a b -> Form m input err a c

Functor m => Functor (Form m input err view)

Defined in Ditto.Core

Methods

fmap :: (a -> b) -> Form m input err view a -> Form m input err view b

(<$) :: a -> Form m input err view b -> Form m input err view a

(Functor m, Monoid view, Monad m) => Applicative (Form m input err view)

Defined in Ditto.Core

Methods

pure :: a -> Form m input err view a

(<*>) :: Form m input err view (a -> b) -> Form m input err view a -> Form m input err view b

liftA2 :: (a -> b -> c) -> Form m input err view a -> Form m input err view b -> Form m input err view c

(*>) :: Form m input err view a -> Form m input err view b -> Form m input err view b

(<*) :: Form m input err view a -> Form m input err view b -> Form m input err view a

(Monad m, Monoid view) => Alternative (Form m input err view)

Defined in Ditto.Core

Methods

empty :: Form m input err view a

(<|>) :: Form m input err view a -> Form m input err view a -> Form m input err view a

some :: Form m input err view a -> Form m input err view [a]

many :: Form m input err view a -> Form m input err view [a]

(Monad m, Monoid view, Semigroup a) => Semigroup (Form m input err view a)

Defined in Ditto.Core

Methods

(<>) :: Form m input err view a -> Form m input err view a -> Form m input err view a

sconcat :: NonEmpty (Form m input err view a) -> Form m input err view a

stimes :: Integral b => b -> Form m input err view a -> Form m input err view a

(Monoid view, Monad m, Semigroup a) => Monoid (Form m input err view a)

Defined in Ditto.Core

Methods

mempty :: Form m input err view a

mappend :: Form m input err view a -> Form m input err view a -> Form m input err view a

mconcat :: [Form m input err view a] -> Form m input err view a

bracketState :: Monad m => FormState m input a -> FormState m input a

newtype MForm m input err view a

This provides a Monad instance which will stop rendering on err. This instance isn't a part of Form because of its undesirable behavior. -XApplicativeDo is generally preferred

Constructors

MForm

Fields

• runMForm :: Form m input err view a

Instances

Functor m => Bifunctor (MForm m input err)

Defined in Ditto.Core

Methods

bimap :: (a -> b) -> (c -> d) -> MForm m input err a c -> MForm m input err b d

first :: (a -> b) -> MForm m input err a c -> MForm m input err b c

second :: (b -> c) -> MForm m input err a b -> MForm m input err a c

(Monad m, Monoid view) => Monad (MForm m input err view)

Defined in Ditto.Core

Methods

(>>=) :: MForm m input err view a -> (a -> MForm m input err view b) -> MForm m input err view b

(>>) :: MForm m input err view a -> MForm m input err view b -> MForm m input err view b

return :: a -> MForm m input err view a

fail :: String -> MForm m input err view a

Functor m => Functor (MForm m input err view)

Defined in Ditto.Core

Methods

fmap :: (a -> b) -> MForm m input err view a -> MForm m input err view b

(<$) :: a -> MForm m input err view b -> MForm m input err view a

(Monoid view, Monad m) => Applicative (MForm m input err view)

Defined in Ditto.Core

Methods

pure :: a -> MForm m input err view a

(<*>) :: MForm m input err view (a -> b) -> MForm m input err view a -> MForm m input err view b

liftA2 :: (a -> b -> c) -> MForm m input err view a -> MForm m input err view b -> MForm m input err view c

(*>) :: MForm m input err view a -> MForm m input err view b -> MForm m input err view b

(<*) :: MForm m input err view a -> MForm m input err view b -> MForm m input err view a

(Monad m, Monoid view) => Alternative (MForm m input err view)

Defined in Ditto.Core

Methods

empty :: MForm m input err view a

(<|>) :: MForm m input err view a -> MForm m input err view a -> MForm m input err view a

some :: MForm m input err view a -> MForm m input err view [a]

many :: MForm m input err view a -> MForm m input err view [a]

runAsMForm :: Monad m => Environment m input -> Text -> Form m input err view a -> m (View err view, m (Result err (Proved a)))

Ways to evaluate a Form

runForm :: Monad m => Environment m input -> Text -> Form m input err view a -> m (View err view, m (Result err (Proved a)))

Run a form

runForm' :: Monad m => Environment m input -> Text -> Form m input err view a -> m (view, Maybe a)

Run a form

viewForm

Arguments

:: Monad m

=> Text

form prefix

-> Form m input err view a

form to view

-> m view

Just evaluate the form to a view. This usually maps to a GET request in the browser.

eitherForm

Arguments

:: Monad m

=> Environment m input

Input environment

-> Text

Identifier for the form

-> Form m input err view a

Form to run

-> m (Either view a)

Result

Evaluate a form

Returns:

Left view

on failure. The view will have already been applied to the errors.

Right a

on success.

view

Arguments

:: Monad m

=> view

View to insert

-> Form m input err view ()

Resulting form

create a Form from some view.

This is typically used to turn markup like <br> into a Form.

(++>) :: (Monad m, Semigroup view) => Form m input err view z -> Form m input err view a -> Form m input err view a infixl 6

Append a unit form to the left. This is useful for adding labels or err fields.

The Forms on the left and right hand side will share the same FormId. This is useful for elements like <label for="someid">, which need to refer to the id of another element.

(<++) :: (Monad m, Semigroup view) => Form m input err view a -> Form m input err view z -> Form m input err view a infixr 5

Append a unit form to the right. See ++>.

mapView

Arguments

:: Functor m

=> (view -> view')

Manipulator

-> Form m input err view a

Initial form

-> Form m input err view' a

Resulting form

Change the view of a form using a simple function

This is useful for wrapping a form inside of a <fieldset> or other markup element.

(@$) :: Monad m => (view -> view) -> Form m input err view a -> Form m input err view a infixr 0

infix mapView: succinct `foo @$ do ..`

mkOk :: Monad m => FormId -> view -> a -> FormState m input (View err view, m (Result err (Proved a)))

Utility Function: turn a view and pure value into a successful FormState