CGIInternals

Brackets a CGI action so that only its result is visible. Improves efficiency by not executing the bracketed action after it has been performed once. Use this for avoiding the inefficient buildup of long interaction logs.

forever :: CGI () -> CGI ()

Repeats a CGI action without saving its state so that the size of the interaction log remains constant.

onceAndThen :: (Read a, Show a) => a -> CGI a -> CGI a

Unsafe variant of once: returns the computed value only the first time and returns a default value in all later invocations.

unsafe_io :: IO a -> CGI a

Directly lifts the IO monad into the CGI monad. This is generally unsafe and should be avoided. Use io instead.

ask :: WithHTML x CGI a -> CGI ()

Takes a monadic value that constructs a HTML page and delivers this page to the browser. This page may contain forms and input widgets.

askOffline :: WithHTML x CGI a -> (Element -> IO ()) -> CGI ()

Like ask, but passes the constructed HTML page to the elementAction parameter. This function may send the page via Email or store it into a file. Anyone loading this page in a browser can resume the interaction.

run :: CGI () -> IO ()

Turns a CGI action into an IO action. Used to turn the main CGI action into the main function of the program. Typical use:

 main = run mainCGI

runWithOptions :: CGIOptions -> CGI () -> IO ()

Turns a CGI action into an IO action. Used to turn the main CGI action into the main function of the program. Takes additional low-level options. Typical use:

 main = runWithOptions [] mainCGI

runWithHook :: CGIOptions -> ([String] -> CGI ()) -> CGI () -> IO ()

Variant of run where an additional argument cgigen specifies an action taken when the script is invoked with a non-empty query string as in script-name?query-string

makeServlet :: CGI () -> CGIProgram

Transform a CGI action into a servlet suitable for running from Marlow's web server.

makeServletWithHook :: ([String] -> CGI ()) -> CGI () -> CGIProgram

Like makeServlet with additional CGI generator as in runWithHook.

makeRef

:: Monad m
=> String	internal name of entity
-> WithHTML x m ()	body of the reference
-> CGI (WithHTML y m ())
Create a hyperlink to internal entity.

makePopupRef

:: String	name of popup window
-> String	internal name of entity
-> HTMLCons x y CGI ()
Create a popup hyperlink to internal entity.

makeA :: String -> String -> HTMLField x y ()

Create hyperlink to internal entity /path?name.

data VALID

Constructors

VALID

data INVALID

Constructors

INVALID

data InputField a x

Constructors

InputField

ifName :: String
ifToken :: CGIFieldName
ifFty :: String
ifString :: (Maybe String)
ifValue :: (Maybe a)
ifRaw :: CGIParameters
ifBound :: Bool

Instances

HasValue InputField

InputHandle (InputField a)

concatFields :: (Reason c, Read c) => InputField c INVALID -> InputField Text INVALID -> InputField c INVALID

create a virtual input field from the concatenation of two input fields

concatFieldsWith :: (Reason c, Read c) => (String -> [String] -> String) -> InputField c INVALID -> [InputField Text INVALID] -> InputField c INVALID

Create a virtual input field from the result of applying a function to two input fields. Parsing is applied to the result of the function call.

feither :: (a -> b) -> (c -> d) -> Either a c -> Either b d

propagate :: Either [err] a -> Either [err] b -> Either [err] (a, b)

data ValidationError

Constructors

ValidationError

veName :: String
veToken :: CGIFieldName
veString :: (Maybe String)

data InputType

Constructors

TEXT
PASSWORD
CHECKBOX
RADIO
SUBMIT
RESET
FILE
HIDDEN
IMAGE
BUTTON

Instances

Show InputType

Eq InputType

textual :: InputType -> Bool

type HTMLField x y a = WithHTML x CGI () -> WithHTML y CGI a

Every input widget maps the content generator for the widget (which may produce HTML elements or attributes) to the content generator of the widget.

resetField :: HTMLField x y (InputField () INVALID)

Creates a reset button that clears all fields of a form.

submitField :: CGI () -> HTMLField x y ()

Creates a submit button. Unsafe. Internal use only.

defaultSubmitField :: CGI () -> HTMLField x y ()

activeInputField

:: (Reason a, Read a)
=> (a -> CGI ())	Function that maps input data to a CGI action.
-> HTMLField x y ()
Creates an input field that submits the field to the browser when data is entered into this field.

activateI :: (a -> CGI ()) -> HTMLField x y (InputField a INVALID) -> HTMLField x y ()

Attach a CGI action to the value returned by the input field. Activation means that data is submitted as soon as it is entered.

inputField :: (Reason a, Read a) => HTMLField x y (InputField a INVALID)

Create a textual input field. Return type can be *anything* in class Reason and Read.

maybeRead :: Read a => String -> Maybe a

textInputField :: HTMLField x y (InputField String INVALID)

Create a textual input field that returns the string entered. (Avoids having to put quotes around a string.)

checkedTextInputField :: (Maybe String -> Maybe String) -> HTMLField x y (InputField String INVALID)

Creates a textual input field that takes a custom validation function.

passwordInputField :: (Reason a, Read a) => HTMLField x y (InputField a INVALID)

Like inputField but the characters are not echoed on the screen.

checkboxInputField :: HTMLField x y (InputField Bool INVALID)

Creates a checkbox. Returns True if box was checked.

fileInputField :: HTMLField x y (InputField FileReference INVALID)

Creates a file input field. Returns a temporary FileReference. The fileReferenceName of the result is *not* guaranteed to be persistent. The application is responsible for filing it away at a safe place.

checkedFileInputField :: (Maybe FileReference -> Maybe FileReference) -> HTMLField x y (InputField FileReference INVALID)

Creates a file input field. Like fileInputField but has an additional parameter for additional validation of the input.

genericField :: Reason a => InputType -> (Maybe String -> Maybe a) -> HTMLField x y (InputField a INVALID)

internalSubmitLink :: Bool -> Either [ValidationError] (CGI ()) -> HTMLCons x y CGI ()

generates a hyperlink that submits the current form.

imageField :: Image -> HTMLField x y (InputField (Int, Int) INVALID)

Create an input field from an image. Returns (x,y) position clicked in the image.

data RadioGroup a x

Constructors

RadioGroup

radioName :: String
radioToken :: CGIFieldName
radioString :: (Maybe String)
radioValue :: (Maybe a)
radioBound :: Bool

Instances

HasValue RadioGroup

InputHandle (RadioGroup a)

radioGroup :: Read a => WithHTML x CGI (RadioGroup a INVALID)

Create a handle for a new radio group. This handle is invisible on the screen!

radioButton :: Show a => RadioGroup a INVALID -> a -> HTMLField x y ()

Create a new radio button and attach it to an existing RadioGroup.

radioError :: RadioGroup a INVALID -> WithHTML x CGI ()

Create and place the error indicator for an existing RadioGroup. Becomes visible only if no button of a radio group is pressed.

makeButton :: HTMLField x y (InputField Bool INVALID)

Create a single button.

makeForm :: WithHTML x CGI a -> WithHTML y CGI ()

Wraps an HTML form around its arguments. All standard attributes are computed and need not be supplied explicitly.

makeTextarea :: String -> HTMLField x y (InputField String INVALID)

Create a text area with a preset string.

selectMultiple

:: Eq a
=> (a -> String)	function to display values of type a
-> [a]	list of preselected entries
-> [a]	list of all possible entries
-> (Int, Int)	(min, max) number of fields that must be selected
-> HTMLField x y (InputField [a] INVALID)
Create a selection box where multiple entries can be selected.

selectSingle

:: Eq a
=> (a -> String)	function to display values of type a
-> Maybe a	optional preselected value
-> [a]	list of all possible values
-> HTMLField x y (InputField a INVALID)
Create a selection box where exactly one entry can be selected.

selectBounded :: (Enum a, Bounded a, Read a, Show a, Eq a) => Maybe a -> HTMLField x y (InputField a INVALID)

Selection box for elements of a Bounded type. Argument is the optional preselected value.

fieldSIZE :: Monad m => Int -> WithHTML x m ()

Create a SIZE attribute from an Int.

fieldMAXLENGTH :: Monad m => Int -> WithHTML x m ()

Create a MAXLENGTH attribute from an Int.

fieldVALUE :: (Monad m, Show a) => a -> WithHTML x m ()

Create a VALUE attribute from any Showable.

tell :: CGIOutput a => a -> CGI ()

Terminates script by sending its argument to the browser.

htell :: WithHTML x IO () -> CGI a

Terminate script by sending a HTML page constructed by monadic argument.

data Image

Constructors

Image

imageSRC :: URL
imageALT :: String

internalImage

:: FreeForm	the raw image
-> String	alternative text
-> WithHTML x CGI Image
Reference to internal image.

dataImage

:: FreeForm	the raw image
-> String	alternative text
-> WithHTML x CGI Image
Reference to internal image via data URL (small images, only).

jsImage

:: FreeForm	the raw image
-> String	alternative text
-> WithHTML x CGI Image
Reference to internal image via javascript URL (does not seem to work).

externalImage

:: URL	URL of image
-> String	alternative text
-> WithHTML x CGI Image
Reference to image by URL.

makeImg :: Image -> HTMLField x y ()

Create an inline image.

frameTranslator :: ([String] -> CGI ()) -> [String] -> CGI ()

docTranslator :: [FreeForm] -> ([String] -> CGI ()) -> [String] -> CGI ()

A translator is a function [String] -> CGI (). It takes the query string of the URL (of type [String]) and translates it into a CGI action. docTranslator docs next takes a list of FreeForm documents and a next translator. It tries to select a document by its ffName and falls through to the next translator if no document matches.

lastTranslator :: [String] -> CGI ()

Terminates a sequence of translators.

reportError :: String -> WithHTML x IO () -> CGIState -> IO (a, CGIState)

backLink :: Monad m => HTMLCons x y m ()

Link to previous page in browser's history. Uses JavaScript.

hlink :: Monad m => URL -> HTMLCons x y m ()

Plain Hyperlink from an URL string.

popuplink :: Monad m => String -> URL -> HTMLCons x y m ()

Hyperlink that creates a named popup window from an URL string.

restart :: CGI ()

restart application.

standardQuery :: String -> WithHTML x CGI a -> CGI ()

Convenient workhorse. Takes the title of a page and a monadic HTML value for the contents of the page. Wraps the contents in a form so that input fields and buttons may be used inside.

tellError :: String -> Element -> CGI a

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