Library for constructing static and dynamic HTML pages. This paper contains a description of the basic ideas behind this library.
A cgi script written with this library can be installed by the command
cypm exec curry2cgi -m mainPage -o /home/joe/public_html/prog.cgi Prog
where Prog
is the name of the Curry program with
the cgi script, /home/joe/public_html/prog.cgi
is
the desired location of the
compiled cgi script, and mainPage
is the Curry expression
(of type IO HtmlPage
) computing the HTML page (where cypm
is the command calling the Curry Package Manager).
Author: Michael Hanus (with extensions by Bernd Brassel and Marco Comini)
Version: July 2020
defaultEncoding
:: String
The default encoding used in generated web pages. |
idOfCgiRef
:: CgiRef -> String
Internal identifier of a CgiRef (intended only for internal use in other libraries!). |
textOf
:: [HtmlExp] -> String
Extracts the textual contents of a list of HTML expressions. |
formDefWithID
:: String -> IO a -> (a -> [HtmlExp]) -> HtmlFormDef a
A definition of a form with a unique identifier of form (usually, the qualified name of the operation defining the form). |
formDefId
:: HtmlFormDef a -> String
Returns the identifier of a form definition. |
instCgiRefs
:: [HtmlExp] -> Int -> ([HtmlExp],Int)
Instantiates all CgiRefs with a unique tag in HTML expressions. |
pageEnc
:: String -> PageParam
An encoding scheme for a HTML page. |
pageCookie
:: (String,String) -> PageParam
A cookie to be sent to the client's browser when a HTML page is requested. |
pageCSS
:: String -> PageParam
A URL for a CSS file for a HTML page. |
pageMetaInfo
:: [(String,String)] -> PageParam
Meta information for a HTML page. |
pageLinkInfo
:: [(String,String)] -> PageParam
Link information for a HTML page. |
pageBodyAttr
:: (String,String) -> PageParam
Optional attribute for the body element of the web page. |
page
:: String -> [HtmlExp] -> HtmlPage
A basic HTML web page with the default encoding. |
standardPage
:: String -> [HtmlExp] -> HtmlPage
A standard HTML web page where the title is included in the body as the first header. |
addPageParam
:: HtmlPage -> PageParam -> HtmlPage
Adds a parameter to an HTML page. |
addCookies
:: [(String,String)] -> HtmlPage -> HtmlPage
Add simple cookie to an HTML page. |
addHttpHeader
:: String -> String -> HtmlPage -> HtmlPage
Add a HTTP header to a HTML page. |
formatCookie
:: (String,String,[CookieParam]) -> String
|
answerText
:: String -> HtmlPage
A textual result instead of an HTML page as a result for active web pages. |
answerEncText
:: String -> String -> HtmlPage
A textual result instead of an HTML page as a result for active web pages where the encoding is given as the first parameter. |
redirectPage
:: String -> HtmlPage
Generates a redirection page to a given URL. |
expires
:: Int -> HtmlPage -> HtmlPage
Adds expire time to given HTML page. |
htxt
:: String -> HtmlExp
Basic text as HTML expression. |
htxts
:: [String] -> [HtmlExp]
A list of strings represented as a list of HTML expressions. |
hempty
:: HtmlExp
An empty HTML expression. |
nbsp
:: HtmlExp
Non breaking Space |
h1
:: [HtmlExp] -> HtmlExp
Header 1 |
h2
:: [HtmlExp] -> HtmlExp
Header 2 |
h3
:: [HtmlExp] -> HtmlExp
Header 3 |
h4
:: [HtmlExp] -> HtmlExp
Header 4 |
h5
:: [HtmlExp] -> HtmlExp
Header 5 |
h6
:: [HtmlExp] -> HtmlExp
Header 6 |
par
:: [HtmlExp] -> HtmlExp
Paragraph |
section
:: [HtmlExp] -> HtmlExp
Section |
header
:: [HtmlExp] -> HtmlExp
Header |
:: [HtmlExp] -> HtmlExp
Footer |
emphasize
:: [HtmlExp] -> HtmlExp
Emphasize |
strong
:: [HtmlExp] -> HtmlExp
Strong (more emphasized) text. |
bold
:: [HtmlExp] -> HtmlExp
Boldface |
italic
:: [HtmlExp] -> HtmlExp
Italic |
:: [HtmlExp] -> HtmlExp
Navigation |
code
:: [HtmlExp] -> HtmlExp
Program code |
center
:: [HtmlExp] -> HtmlExp
Centered text |
blink
:: [HtmlExp] -> HtmlExp
Blinking text |
teletype
:: [HtmlExp] -> HtmlExp
Teletype font |
pre
:: [HtmlExp] -> HtmlExp
Unformatted input, i.e., keep spaces and line breaks and don't quote special characters. |
verbatim
:: String -> HtmlExp
Verbatim (unformatted), special characters (<,>,&,") are quoted. |
address
:: [HtmlExp] -> HtmlExp
Address |
href
:: String -> [HtmlExp] -> HtmlExp
Hypertext reference |
anchor
:: String -> [HtmlExp] -> HtmlExp
An anchored text with a hypertext reference inside a document. |
ulist
:: [[HtmlExp]] -> HtmlExp
Unordered list. |
ulistWithClass
:: String -> String -> [[HtmlExp]] -> HtmlExp
An unordered list with classes for the entire list and the list elements. |
ulistWithItemClass
:: String -> [(String,[HtmlExp])] -> HtmlExp
An unordered list with classes for the entire list individual classes for the list elements. |
olist
:: [[HtmlExp]] -> HtmlExp
Ordered list. |
olistWithClass
:: String -> String -> [[HtmlExp]] -> HtmlExp
An ordered list with classes for the entire list and the list elements. |
olistWithItemClass
:: String -> [(String,[HtmlExp])] -> HtmlExp
An ordered list with classes for the entire list individual classes for the list elements. |
litem
:: [HtmlExp] -> HtmlExp
A single list item (usually not explicitly used) |
dlist
:: [([HtmlExp],[HtmlExp])] -> HtmlExp
Description list |
table
:: [[[HtmlExp]]] -> HtmlExp
Table with a matrix of items where each item is a list of HTML expressions. |
tableWithClass
:: String -> String -> String -> [[[HtmlExp]]] -> HtmlExp
Table with a matrix of items (each item is a list of HTML expressions) with classes for the entire table, each row, and each data element. |
headedTable
:: [[[HtmlExp]]] -> HtmlExp
Similar to table but introduces header tags for the first row.
|
addHeadings
:: HtmlExp -> [[HtmlExp]] -> HtmlExp
Add a row of items (where each item is a list of HTML expressions) as headings to a table. |
hrule
:: HtmlExp
Horizontal rule |
breakline
:: HtmlExp
Break a line |
image
:: String -> String -> HtmlExp
Image |
styleSheet
:: String -> HtmlExp
Defines a style sheet to be used in this HTML document. |
style
:: String -> [HtmlExp] -> HtmlExp
Provides a style for HTML elements. |
textstyle
:: String -> String -> HtmlExp
Provides a style for a basic text. |
blockstyle
:: String -> [HtmlExp] -> HtmlExp
Provides a style for a block of HTML elements. |
inline
:: [HtmlExp] -> HtmlExp
Joins a list of HTML elements into a single HTML element. |
block
:: [HtmlExp] -> HtmlExp
Joins a list of HTML elements into a block. |
formExp
:: HtmlFormDef a -> HtmlExp
A form embedded in an HTML expression. |
button
:: String -> ((CgiRef -> String) -> IO HtmlPage) -> HtmlExp
A button to submit a form with a label string and an event handler. |
resetButton
:: String -> HtmlExp
Reset button with a label string |
imageButton
:: String -> ((CgiRef -> String) -> IO HtmlPage) -> HtmlExp
Submit button in form of an imag. |
textField
:: CgiRef -> String -> HtmlExp
Input text field with a reference and an initial contents |
password
:: CgiRef -> HtmlExp
Input text field (where the entered text is obscured) with a reference |
textArea
:: CgiRef -> (Int,Int) -> String -> HtmlExp
Input text area with a reference, height/width, and initial contents |
checkBox
:: CgiRef -> String -> HtmlExp
A checkbox with a reference and a value. |
checkedBox
:: CgiRef -> String -> HtmlExp
A checkbox that is initially checked with a reference and a value. |
radioMain
:: CgiRef -> String -> HtmlExp
A main button of a radio (initially "on") with a reference and a value. |
radioMainOff
:: CgiRef -> String -> HtmlExp
A main button of a radio (initially "off") with a reference and a value. |
radioOther
:: CgiRef -> String -> HtmlExp
A further button of a radio (initially "off") with a reference (identical to the main button of this radio) and a value. |
selection
:: CgiRef -> [(String,String)] -> HtmlExp
A selection button with a reference and a list of name/value pairs. |
selectionInitial
:: CgiRef -> [(String,String)] -> Int -> HtmlExp
A selection button with a reference, a list of name/value pairs, and a preselected item in this list. |
multipleSelection
:: CgiRef -> [(String,String,Bool)] -> HtmlExp
A selection button with a reference and a list of name/value/flag pairs. |
:: String -> String -> HtmlExp
A hidden field to pass a value referenced by a fixed name. |
htmlQuote
:: String -> String
Quotes special characters ( < ,> ,& ," , umlauts) in a string
as HTML special characters.
|
htmlIsoUmlauts
:: String -> String
Translates umlauts in iso-8859-1 encoding into HTML special characters. |
addAttr
:: HtmlExp -> (String,String) -> HtmlExp
Adds an attribute (name/value pair) to an HTML element. |
addAttrs
:: HtmlExp -> [(String,String)] -> HtmlExp
Adds a list of attributes (name/value pair) to an HTML element. |
addClass
:: HtmlExp -> String -> HtmlExp
Adds a class attribute to an HTML element (if the class attribute is not empty). |
showHtmlExps
:: [HtmlExp] -> String
Transforms a list of HTML expressions into string representation. |
showHtmlExp
:: HtmlExp -> String
Transforms a single HTML expression into string representation. |
showHtmlPage
:: HtmlPage -> String
Transforms HTML page into string representation. |
htmlPrelude
:: String
Standard header for generated HTML pages. |
htmlTagAttrs
:: [(String,String)]
Standard attributes for element "html". |
getUrlParameter
:: IO String
Gets the parameter attached to the URL of the script. |
urlencoded2string
:: String -> String
Translates urlencoded string into equivalent ASCII string. |
string2urlencoded
:: String -> String
Translates arbitrary strings into equivalent urlencoded string. |
getCookies
:: IO [(String,String)]
Gets the cookies sent from the browser for the current CGI script. |
coordinates
:: (CgiRef -> String) -> Maybe (Int,Int)
For image buttons: retrieve the coordinates where the user clicked within the image. |
The (abstract) data type for representing references to input elements in HTML forms.
Constructors:
The type for representing cgi environments (i.e., mappings from cgi references to the corresponding values of the input elements).
Type synonym: CgiEnv = CgiRef -> String
The type of event handlers occurring in HTML forms.
Type synonym: HtmlHandler = CgiEnv -> IO HtmlPage
The data type for representing HTML expressions.
Constructors:
HtmlText
:: String -> HtmlExp
: a text string without any further structure
HtmlStruct
:: String -> [(String,String)] -> [HtmlExp] -> HtmlExp
: a structure with a tag, attributes, and
HTML expressions inside the structure
HtmlCRef
:: HtmlExp -> CgiRef -> HtmlExp
: an input element (described by the first argument)
with a cgi reference
HtmlEvent
:: HtmlExp -> CgiRef -> HtmlHandler -> HtmlExp
: an input element (first arg) identified
by a cgi reference with an associated
event handler (typically, a submit button)
HtmlAction
:: (IO HtmlExp) -> HtmlExp
: an action that computes an HTML expression
which will be inserted when the HTML document is shown
The data type for representing HTML forms embedded into HTML pages.
A form definition consists of a unique identifier of form (usually, the qualified name of the operation defining the form), a (reading!) IO action and a mapping from data into an HTML expression (which usually contains event handlers to produce the form answers). It is assumed that the IO action reads only data and does not change it, since it is applied twice when executing a form.
Constructors:
HtmlFormDef
:: String -> (IO a) -> (a -> [HtmlExp]) -> HtmlFormDef a
The data type for representing HTML pages.
Constructors:
HtmlPage
:: String -> [PageParam] -> [HtmlExp] -> HtmlPage
: an HTML page with title t, optional parameters
(e.g., cookies) ps, and contents hs
HtmlAnswer
:: String -> String -> HtmlPage
: an answer in an arbitrary format where t
is the content type (e.g., "text/plain") and c is the contents
The possible parameters of an HTML page.
The parameters of a cookie (PageCookie
) are its name and value and
optional parameters (expiration date, domain, path (e.g., the path "/"
makes the cookie valid for all documents on the server), security) which
are collected in a list.
Constructors:
PageEnc
:: String -> PageParam
: the encoding scheme of this page
PageCookie
:: String -> String -> [CookieParam] -> PageParam
: a cookie to be sent to the
client's browser
PageCSS
:: String -> PageParam
: a URL for a CSS file for this page
HttpHeader
:: String -> String -> PageParam
: additional HTTP header included in this page
PageJScript
:: String -> PageParam
: a URL for a Javascript file for this page
PageMeta
:: [(String,String)] -> PageParam
: meta information (in form of attributes) for this page
PageLink
:: [(String,String)] -> PageParam
: link information (in form of attributes) for this page
PageHeadInclude
:: HtmlExp -> PageParam
: HTML expression to be included in page header
PageBodyAttr
:: (String,String) -> PageParam
: optional attribute for the body element of the
page (more than one occurrence is allowed)
The possible parameters of a cookie.
Constructors:
CookieExpire
:: ClockTime -> CookieParam
CookieDomain
:: String -> CookieParam
CookiePath
:: String -> CookieParam
CookieSecure
:: CookieParam
The default encoding used in generated web pages.
|
Internal identifier of a CgiRef (intended only for internal use in other libraries!).
|
Extracts the textual contents of a list of HTML expressions. For instance, textOf [HtmlText "xy", HtmlStruct "a" [] [HtmlText "bc"]] == "xy bc" |
A definition of a form with a unique identifier of form (usually, the qualified name of the operation defining the form). A form contains a (reading!) IO action and a mapping from data into an HTML expression (which usually contains event handlers to produce the form answers). It is assumed that the IO action reads only data and does not change it, since it is applied twice when executing a form.
|
Returns the identifier of a form definition.
|
Instantiates all CgiRefs with a unique tag in HTML expressions. Only internally used.
|
An encoding scheme for a HTML page.
|
A cookie to be sent to the client's browser when a HTML page is requested.
|
A URL for a CSS file for a HTML page.
|
Meta information for a HTML page. The argument is a list of
attributes included in the
|
Link information for a HTML page. The argument is a list of
attributes included in the
|
Optional attribute for the body element of the web page. More than one occurrence is allowed, i.e., all such attributes are collected.
|
A basic HTML web page with the default encoding.
|
A standard HTML web page where the title is included in the body as the first header.
|
Adds a parameter to an HTML page.
|
Add simple cookie to an HTML page. The cookies are sent to the client's browser together with this page.
|
Add a HTTP header to a HTML page. Headers are sent to the client's browser together with the page.
|
|
A textual result instead of an HTML page as a result for active web pages.
|
A textual result instead of an HTML page as a result for active web pages where the encoding is given as the first parameter.
|
Generates a redirection page to a given URL.
This is implemented via the HTTP response header
|
Adds expire time to given HTML page.
|
Basic text as HTML expression. The text may contain special HTML chars (like <,>,&,") which will be quoted so that they appear as in the parameter string. |
A list of strings represented as a list of HTML expressions. The strings may contain special HTML chars that will be quoted. |
An empty HTML expression.
|
Non breaking Space
|
Header 1
|
Header 2
|
Header 3
|
Header 4
|
Header 5
|
Header 6
|
Paragraph
|
Section
|
Header
|
Emphasize
|
Strong (more emphasized) text.
|
Boldface
|
Italic
|
Program code
|
Centered text
|
Blinking text
|
Teletype font
|
Unformatted input, i.e., keep spaces and line breaks and don't quote special characters.
|
Address
|
Hypertext reference
|
An anchored text with a hypertext reference inside a document.
|
Unordered list.
|
An unordered list with classes for the entire list and the list elements. The class annotation will be ignored if it is empty.
|
An unordered list with classes for the entire list individual classes for the list elements. The class annotation will be ignored if it is empty.
|
Ordered list.
|
An ordered list with classes for the entire list and the list elements. The class annotation will be ignored if it is empty.
|
An ordered list with classes for the entire list individual classes for the list elements. The class annotation will be ignored if it is empty.
|
A single list item (usually not explicitly used)
|
Description list
|
Table with a matrix of items where each item is a list of HTML expressions. |
Table with a matrix of items (each item is a list of HTML expressions) with classes for the entire table, each row, and each data element. The class annotation will be ignored if it is empty.
|
Similar to |
Add a row of items (where each item is a list of HTML expressions) as headings to a table. If the first argument is not a table, the headings are ignored. |
Horizontal rule
|
Break a line
|
Image
|
Defines a style sheet to be used in this HTML document.
|
Provides a style for HTML elements.
The style argument is the name of a style class defined in a
style definition (see
|
Provides a style for a basic text. The style argument is the name of a style class defined in an external style sheet.
|
Provides a style for a block of HTML elements. The style argument is the name of a style class defined in an external style sheet. This element is used (in contrast to "style") for larger blocks of HTML elements since a line break is placed before and after these elements.
|
Joins a list of HTML elements into a single HTML element. Although this construction has no rendering, it is sometimes useful for programming when several HTML elements must be put together.
|
Joins a list of HTML elements into a block. A line break is placed before and after these elements.
|
A form embedded in an HTML expression.
The parameter is a form defined as an exported top-level operation
in the CGI program so that it can be accessed by the main program.
The URL of the generated form is the same as the main page, i.e.,
the current URL parameter is passed to the form (which is
useful for REST-based programming with URL parameters).
The form uses a hidden field named |
A button to submit a form with a label string and an event handler. |
Reset button with a label string |
Submit button in form of an imag.
|
Input text field (where the entered text is obscured) with a reference |
Input text area with a reference, height/width, and initial contents |
A checkbox with a reference and a value. The value is returned if checkbox is on, otherwise "" is returned. |
A checkbox that is initially checked with a reference and a value. The value is returned if checkbox is on, otherwise "" is returned. |
A main button of a radio (initially "on") with a reference and a value. The value is returned of this button is on. A complete radio button suite always consists of a main button (radiomain) and some further buttons (radioothers) with the same reference. Initially, the main button is selected (or nothing is selected if one uses radiomainoff instead of radio_main). The user can select another button but always at most one button of the radio can be selected. The value corresponding to the selected button is returned in the environment for this radio reference. |
A main button of a radio (initially "off") with a reference and a value. The value is returned of this button is on. |
A further button of a radio (initially "off") with a reference (identical to the main button of this radio) and a value. The value is returned of this button is on. |
A selection button with a reference and a list of name/value pairs. The names are shown in the selection and the value is returned for the selected name. |
A selection button with a reference, a list of name/value pairs, and a preselected item in this list. The names are shown in the selection and the value is returned for the selected name.
|
A selection button with a reference and a list of name/value/flag pairs.
The names are shown in the selection and the value is returned
if the corresponding name is selected. If flag is True, the
corresonding name is initially selected. If more than one name
has been selected, all values are returned in one string
where the values are separated by newline ( |
Quotes special characters ( |
Translates umlauts in iso-8859-1 encoding into HTML special characters. |
Adds an attribute (name/value pair) to an HTML element.
|
Adds a list of attributes (name/value pair) to an HTML element.
|
Adds a class attribute to an HTML element (if the class attribute is not empty).
|
Transforms a list of HTML expressions into string representation. |
Transforms a single HTML expression into string representation. |
Transforms HTML page into string representation.
|
Standard header for generated HTML pages.
|
Standard attributes for element "html".
|
Gets the parameter attached to the URL of the script. For instance, if the script is called with URL "http://.../script.cgi?parameter", then "parameter" is returned by this I/O action. Note that an URL parameter should be "URL encoded" to avoid the appearance of characters with a special meaning. Use the functions "urlencoded2string" and "string2urlencoded" to decode and encode such parameters, respectively. |
Translates urlencoded string into equivalent ASCII string. |
Translates arbitrary strings into equivalent urlencoded string. |
Gets the cookies sent from the browser for the current CGI script. The cookies are represented in the form of name/value pairs since no other components are important here. |
For image buttons: retrieve the coordinates where the user clicked within the image. |