tomjnixon · December 24, 2010 14:59
diff --git a/template.hs b/template.hs
 import Control.Monad.State

 -- Append a string to the state.
 string :: String -> State [String] ()
 string s = State $ \ss -> ((), ss ++ [s])

 -- Get the string out of the state.
 to_str (State ss) = concat $ b
 	where (a, b) = ss []

 -- HTML stuff.

 -- Format a html argument list.
 format_arglist ((key, val) : xs) = " " ++ key ++ "=\"" ++ val ++ "\"" ++ format_arglist xs
 format_arglist [] = ""

 -- Format a tag with a name, some arguments and a body.
 tag name args contents = do
 	string $ "<" ++ name ++ format_arglist args ++ ">"
 	contents
 	string $ "</" ++ name ++ ">"

 -- Some example tags.
 ul = tag "ul"
 li = tag "li"
 emph = tag "emph" []

 -- A 'normal' html page with a title and a body.
 html title body = do
 	tag "html" [] $ do
 		tag "head" [] $ do
 			tag "title" [] $ string title
 		tag "body" [] body

 -- An example
 my_html = to_str $ html "test page" $ do
 	string "Here is a list:"
 	
 	ul [("class", "zomg")] $ do
 		li [] $ string "foo"
 		li [] $ do
 			string "some "
 			emph $ string "bold"
 			string " text"
 		li [] $ string "baz"
 	
 	string "done!"

 -- This should print:
 -- <html><head><title>test page</title></head><body>Here is a list:
 -- <ul class="zomg"><li>foo</li><li>some <emph>bold</emph> text</li>
 -- <li>baz</li></ul>done!</body></html>
 main = putStrLn my_html
	import Control.Monad.State

	-- Append a string to the state.
	string :: String -> State [String] ()
	string s = State $ \ss -> ((), ss ++ [s])

	-- Get the string out of the state.
	to_str (State ss) = concat $ b
	where (a, b) = ss []

	-- HTML stuff.

	-- Format a html argument list.
	format_arglist ((key, val) : xs) = " " ++ key ++ "=\"" ++ val ++ "\"" ++ format_arglist xs
	format_arglist [] = ""

	-- Format a tag with a name, some arguments and a body.
	tag name args contents = do
	string $ "<" ++ name ++ format_arglist args ++ ">"
	contents
	string $ "</" ++ name ++ ">"

	-- Some example tags.
	ul = tag "ul"
	li = tag "li"
	emph = tag "emph" []

	-- A 'normal' html page with a title and a body.
	html title body = do
	tag "html" [] $ do
	tag "head" [] $ do
	tag "title" [] $ string title
	tag "body" [] body

	-- An example
	my_html = to_str $ html "test page" $ do
	string "Here is a list:"

	ul [("class", "zomg")] $ do
	li [] $ string "foo"
	li [] $ do
	string "some "
	emph $ string "bold"
	string " text"
	li [] $ string "baz"

	string "done!"

	-- This should print:
	-- <html><head><title>test page</title></head><body>Here is a list:
	-- <ul class="zomg"><li>foo</li><li>some <emph>bold</emph> text</li>
	-- <li>baz</li></ul>done!</body></html>
	main = putStrLn my_html