Web/Libraries/Formlets
From HaskellWiki
(Difference between revisions)
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The input function takes a Maybe String, and produces a XHtmlForm String. The Maybe String is used for default values. If you give it a nothing, it won't have a default value. If you pass in a (Just "value"), it will be pre-populated with the value "value". | The input function takes a Maybe String, and produces a XHtmlForm String. The Maybe String is used for default values. If you give it a nothing, it won't have a default value. If you pass in a (Just "value"), it will be pre-populated with the value "value". | ||
| + | |||
| + | You can easily combine formlets using the combinators from Applicative. Suppose you have a User-datatype: | ||
| + | |||
| + | <haskell> | ||
| + | data User = User {name :: String, age :: Integer, email :: String} | ||
| + | </haskell> | ||
| + | |||
| + | You can then build a form that produces a user: | ||
| + | |||
| + | <haskell> | ||
| + | userForm :: Form User | ||
| + | userForm = User <$> name <*> inputInteger <*> input Nothing | ||
| + | </haskell> | ||
== The basics == | == The basics == | ||
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== References == | == References == | ||
| - | + | * [http://hackage.haskell.org/cgi-bin/hackage-scripts/package/formlets Formlets library on hackage] | |
| + | * [http://groups.inf.ed.ac.uk/links/formlets/ Papers on formlets] | ||
Revision as of 09:07, 12 August 2008
Contents |
1 Introduction
Formlets are a way of building HTML forms that are type-safe, handle errors, abstract and are easy to combine into bigger forms. Here's an example:
name :: XHtmlForm String name = input Nothing
The input function takes a Maybe String, and produces a XHtmlForm String. The Maybe String is used for default values. If you give it a nothing, it won't have a default value. If you pass in a (Just "value"), it will be pre-populated with the value "value".
You can easily combine formlets using the combinators from Applicative. Suppose you have a User-datatype:
data User = User {name :: String, age :: Integer, email :: String}
You can then build a form that produces a user:
userForm :: Form User userForm = User <$> name <*> inputInteger <*> input Nothing
