diff --git a/CCMain.hs b/CCMain.hs new file mode 100644 --- /dev/null +++ b/CCMain.hs @@ -0,0 +1,67 @@ +------------------------------------------------------------------------------------------ +-- CleverCSS in Haskell, (c) 2007 Georg Brandl. Licensed under the BSD license. +-- +-- Main module: command-line interface. +------------------------------------------------------------------------------------------ + +module Main (main) where + +import Control.Monad (when) +import Data.List (findIndices) +import System +import System.Console.GetOpt +import System.IO + +import Text.CSS.CleverCSS + +-- read an option definition from a command line option +readDef arg = case span (/= '=') arg of + (_, "") -> error "invalid variable definition, must be name=value" + (_, "=") -> error "empty variable value" + (name, val) -> (name, tail val) + +optdescr = [Option "D" [] (ReqArg readDef "name=value") "define a variable", + Option "h" ["help"] (NoArg ("help","")) "print this help message"] + +help errs = do + pname <- getProgName + when ((not.null) errs) $ putStrLn $ concat errs + putStrLn (usageInfo ("Usage: " ++ pname ++ " [opts] [file ...]\n\ + \\n\ + \With file names, read these and convert them to CSS files.\n\ + \The output file name is determined by stripping the input\n\ + \file names' extensions and adding `.css'. Existing files are\n\ + \overwritten.\n\ + \Without file names, read from stdin and write to stdout.\n\n\ + \Options:\n") optdescr) + +main :: IO () +main = do + rawargs <- getArgs + let (defs, args, errs) = getOpt Permute optdescr rawargs + if (not.null) errs || ("help","") `elem` defs then help errs else + case length args of + 0 -> process getContents "stdin" stdout defs >> return () + _ -> mapM_ (processFile defs) args + where + processFile defs filename = do + let outfilename = case findIndices (=='.') filename of + [] -> filename ++ ".css" + is -> take (last is) filename ++ ".css" + if outfilename == filename then + fail $ "Input and output filenames are equal: " ++ filename + else do + outfile <- openFile outfilename WriteMode + result <- process (readFile filename) filename outfile defs + hClose outfile + when result $ putStr $ + "Converted file " ++ filename ++ " to " ++ outfilename ++ ".\n" + process inaction filename outfile defs = do + input <- inaction + case cleverCSSConvert filename input defs of + Left err -> do + hPutStr stderr $ "While processing " ++ filename ++ ":\n" ++ err ++ "\n" + return False + Right out -> do + hPutStr outfile out + return True diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,29 @@ +Copyright (c) by Georg Brandl. All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are +met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following + disclaimer in the documentation and/or other materials provided + with the distribution. + + * The names of the contributors may not be used to endorse or + promote products derived from this software without specific + prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. diff --git a/Setup.lhs b/Setup.lhs new file mode 100644 --- /dev/null +++ b/Setup.lhs @@ -0,0 +1,4 @@ +#! /usr/bin/env runhaskell + +> import Distribution.Simple +> main = defaultMain diff --git a/Text/CSS/CleverCSS.hs b/Text/CSS/CleverCSS.hs new file mode 100644 --- /dev/null +++ b/Text/CSS/CleverCSS.hs @@ -0,0 +1,477 @@ +------------------------------------------------------------------------------------------ +-- CleverCSS in Haskell, (c) 2007 Georg Brandl. Licensed under the BSD license. +-- +-- CleverCSS module: main parsing and evaluation. +-- +-- TODO: properly parse selectors before splitting them +------------------------------------------------------------------------------------------ +{-# LANGUAGE PatternGuards #-} + +module Text.CSS.CleverCSS (cleverCSSConvert) where + +import Control.Monad.Error +import Control.Monad.RWS +import Data.Char (toUpper, toLower) +import Data.List (findIndex) +import Text.Printf (printf) +import Text.ParserCombinators.Parsec hiding (newline) +import qualified Data.Map as Map + +import Text.CSS.CleverCSSUtil + +css_functions = ["url", "attr", "counter"] -- rgb() is special + +------------------------------------------------------------------------------------------ +-- "AST" for clevercss templates + +type CSSNumber = (Rational, String) -- number, unit +type CSSColor = Either String Color -- color name or RGB +data AssignType = Always | IfNotAssigned deriving Eq + +data Topl = Assign !AssignType !Line !String [Expr] + | Import !Line [Expr] + | Block !Line ![String] [Item] + deriving Eq +data Item = Property !Line !String [Expr] + | SubBlock !Line ![String] [Item] + | SubGroup !Line !String [Item] + deriving Eq +data Expr = Plus Expr Expr | Minus Expr Expr + | Mul Expr Expr | Divide Expr Expr | Modulo Expr Expr + | ExprListCons Expr Expr | ExprList [Expr] | Subseq [Expr] + | Call Expr !String (Maybe Expr) + | Var !String | Bare !String | String !String | CSSFunc !String Expr + | Number !Rational | Dim !CSSNumber | Color !CSSColor | Rgb Expr Expr Expr + | Error !String + deriving Eq + +instance Show Topl where + show (Assign Always _ name exprs) = name ++ " = " ++ joinShow " " exprs + show (Assign IfNotAssigned _ name exprs) = name ++ " ?= " ++ joinShow " " exprs + show (Import _ exprs) = "@import " ++ joinShow " " exprs + show (Block _ sels items) = (joinStr ", " sels) ++ ":\n" ++ + unlines (map (" "++) (map show items)) + +instance Show Item where + show (Property _ name exprs) = name ++ ": " ++ joinShow " " exprs + show (SubGroup _ name items) = name ++ "->\n" ++ + unlines (map (" "++) (map show items)) + show (SubBlock _ sels items) = (joinStr ", " sels) ++ ":\n" ++ + unlines (map (" "++) (map show items)) + +instance Show Expr where + -- things that shouldn't remain when evaluated + show (Plus a b) = printf "" (show a) (show b) + show (Minus a b) = printf "" (show a) (show b) + show (Mul a b) = printf "" (show a) (show b) + show (Divide a b) = printf "" (show a) (show b) + show (Modulo a b) = printf "" (show a) (show b) + show (ExprListCons a b) = printf "" (show a) (show b) + show (Call e n Nothing) = printf "" (show e) n + show (Call e n (Just a)) = printf "" (show e) n (show a) + show (Var a) = printf "" a + show (Rgb r g b) = printf "" (show r) (show g) (show b) + show (Error e) = printf "" e + -- things that can remain and need to be pretty-printed + show (ExprList l) = joinShow ", " l + show (Subseq l) = joinShow " " l + show (String s) = cssShow s + show (Number n) = show (fromRational n) + show (Dim (n, u)) = show (fromRational n) ++ u + show (CSSFunc name args) = name ++ "(" ++ show args ++ ")" + show (Color (Left n)) = n + show (Color (Right (r,g,b))) = case Map.lookup (r,g,b) reverse_colors of + Just name -> name + Nothing -> printf "#%02x%02x%02x" r g b + show (Bare s) = s + +------------------------------------------------------------------------------------------ +-- the tokenizer and parser + +-- helpers for toplevel and expression parsers +nl = char '\n' "end of line" +ws = many (char ' ') "whitespace" +comment = string "//" >> many (noneOf "\n") "comment" +wscomment = ws >> option "" (try comment) +emptyLine = wscomment >> nl "empty line" +-- a newline always consumes empty lines too -- different from many1 emptyLine! +newline = emptyLine >> many (try emptyLine) "newline" +pws parser = parser ~>> wscomment +-- a CSS identifier +ident = (pws $ try $ (perhaps $ char '-') +++ + ((char '_' <|> letter <|> escape) +:+ + many (char '_' <|> char '-' <|> alphaNum <|> escape))) + "identifier" +escape = char '\\' >> (uniescape <|> charescape) +uniescape = (varCount 1 6 hexDigit ~>> perhaps (oneOf " \n")) + >>= (return . hexToString) +charescape = noneOf ("\n" ++ ['0'..'9'] ++ ['a'..'f'] ++ ['A'..'F']) +at_ident = (char '@' >> ident) "at-identifier" +varname = (char '_' <|> letter) +:+ many (char '_' <|> alphaNum) + +-- top-level parser +parser :: GenParser Char [Int] [Topl] +parser = many emptyLine >> many (import_ <|> assign <|> cassign <|> block) ~>> end + where + import_ = do + atid <- at_ident + if atid == "import" then liftM2 Import getline exprseq_nl + else unexpected "at-identifier, expecting @import" + assign = liftM3 (Assign Always) getline varassign exprseq_nl + cassign = liftM3 (Assign IfNotAssigned) getline cvarassign exprseq_nl + block = do + line <- getline + selectornames <- selector False + firstitem <- subblock True <|> subgroup True <|> property True + restitems <- many $ (subblock False <|> subgroup False <|> property False) + updateState tail + return $! Block line selectornames (firstitem:restitems) + subblock fst = do + line <- getline + selectornames <- selector fst + firstitem <- subblock True <|> subgroup True <|> property True + restitems <- many $ (subblock False <|> subgroup False <|> property False) + updateState tail + return $! SubBlock line selectornames (firstitem:restitems) + subgroup fst = do + line <- getline + groupname <- grpname fst + firstitem <- property True + restitems <- many $ property False + updateState tail + return $! SubGroup line groupname (firstitem:restitems) + property fst = liftM3 Property getline (propname fst) exprseq_nl + selector fst = do + names <- selnames fst + return $! map trim (split "," names) -- XXX: breaks with fancy selectors + + -- position helper + getline = liftM sourceLine getPosition + + -- toplevel variable assignment + varassign = (try $ varname ~>> (ws >> char '=' >> ws)) "assignment" + cvarassign = (try $ varname ~>> (ws >> string "?=" >> ws)) "assignment" + + -- grouping constructs -- fst means, first thing in a block + selnames fst = (try $ indented fst $ --string "def " >> ws >> + noneOf "\n" `manyTill` (try $ char ':' >> newline)) + "selectors" + propname fst = (try $ indented fst $ ident ~>> char ':') "property name" + grpname fst = (try $ indented fst $ grpident ~>> (string "->" >> newline)) + "group name" + grpident = (pws $ try $ many1 letter +++ + manyConcat (try $ char '-' +:+ many1 letter)) + manyConcat = liftM concat . many + end = ((try $ string "__END__" >> nl) >> return ()) <|> eof + + -- indentation handling: for the first thing in a block, need a new indentation + -- level, after that, the same -- the new level is popped from the stack in the + -- individual block parsers + indented fst parser = do + ind <- ws + tok <- parser + state <- getState + let ilen = length ind + olen = head state + if fst then if ilen > olen then do + setState (length ind : state) + return tok + else unexpected "indentation" + else if ilen == olen then return tok else unexpected "indentation level" + +-- expression parser +exprseq_nl = exprseq ~>> (option ';' (char ';') >> newline) + +exprseq :: GenParser Char [Int] [Expr] +exprseq = ws >> many1 expression + where + expression = plusExpr `chainr1` listOp + listOp = op ',' >> return ExprListCons + plusOp = (op '+' >> return Plus) <|> (op '-' >> return Minus) + plusExpr = mulExpr `chainl1` plusOp + mulOp = (op '*' >> return Mul) <|> (op '/' >> return Divide) <|> + (op '%' >> return Modulo) + mulExpr = primary `chainl1` mulOp + primary = do + object <- parenthesized <|> str <|> dimension <|> number <|> color <|> + func <|> rgb <|> var <|> bare + calltails object + parenthesized = liftM Subseq $ between (op '(') (op ')') (many1 expression) + str = liftM String $ (sqstring <|> dqstring) + number = liftM (Number . readNum) num + dimension = liftM (Dim . readDim) dim + color = liftM (Color . Right . hexToColor) hexcolor + var = liftM Var varref + bare = do + name <- ident + if Map.member name colors then return $ Color (Left name) + else return $ Bare name + func = do + funcname <- choice (map funcall css_functions) + args <- expression + op ')' + return $! CSSFunc funcname args + rgb = do + funcall "rgb" + channels <- expression -- r, g, b + op ')' + case channels of (ExprListCons _ (ExprListCons _ (ExprListCons _ _))) -> + fail "too many arguments for rgb()" + (ExprListCons a (ExprListCons b c)) -> + return $! Rgb a b c + _ -> fail "not enough expressions for rgb()" + calltails object = do + calltail <- option Nothing (call object) + case calltail of + Nothing -> return object + Just called -> calltails called + call object = do + methname <- methcall + callexpr <- option Nothing (liftM Just expression) + op ')' + return $! Just (Call object methname callexpr) + + -- tokens appearing within expressions, always parsed with trailing + -- whitespace discarded + varref = (pws $ char '$' >> varname) "variable reference" + funcall fn = (pws $ try $ string fn ~>> char '(') "function " ++ fn + methcall = (pws $ char '.' >> varname ~>> (ws >> char '(')) "method call" + num = (pws $ (perhaps $ char '-') +++ many1 digit +++ + option "" (char '.' +:+ many1 digit)) "number" + dim = (pws $ try $ num +++ ws +++ unit) "dimension" + unit = choice (map string + ["em", "ex", "px", "cm", "mm", "in", "pt", "pc", "deg", + "rad", "grad", "ms", "s", "Hz", "kHz", "%"]) + dqstring = (pws $ char '"' >> many1 (noneOf "\n\\\"" <|> escape) ~>> char '"') + "string" + sqstring = (pws $ char '\'' >> many1 (noneOf "\n\\'" <|> escape) ~>> char '\'') + "string" + hexcolor = (pws $ char '#' >> ((try $ count 6 hexDigit) <|> count 3 hexDigit)) + "color" + op c = (pws $ char c) "operator " ++ [c] + +------------------------------------------------------------------------------------------ +-- the evaluator + +data EvalError = EvalErr !Line !String -- line, message +type EvalMonad = RWST (Map.Map String Expr) () [Topl] (Either EvalError) () + +instance Error EvalError where + strMsg s = EvalErr 0 s + +instance Show EvalError where + show (EvalErr 0 msg) = ": " ++ msg + show (EvalErr l msg) = "(line " ++ show l ++ "):\n" ++ msg + +translate :: [Topl] -> [(String, String)] -> Either EvalError [Topl] +translate toplevels initial_map = + fmap fst $ execRWST (resolve_toplevels toplevels) (eval_map Map.empty initial_map) [] + where + -- evaluate items in the initial map + eval_map :: Map.Map String Expr -> [(String, String)] -> Map.Map String Expr + eval_map map [] = map + eval_map map ((n,v):ds) = eval_map (Map.insert n + (evaluate map "initial variables" v) map) ds + + -- this keeps a state of all collected blocks. + -- it returns (Left error) or (Right ([evaluated blocks], ())) + resolve_toplevels :: [Topl] -> EvalMonad + resolve_toplevels (Block line sels items : ts) = do + resolve_block line sels items + resolve_toplevels ts + resolve_toplevels (Import line exprseq : ts) = do + exprs <- eval_exprseq exprseq + case exprs of + CSSFunc "url" u -> modify (Import line [CSSFunc "url" u] : ) + v -> throwError $ EvalErr line $ + "invalid thing to import, should be url(): " ++ show v + resolve_toplevels ts + resolve_toplevels (Assign how line name exprseq : ts) = do + ispresent <- asks (Map.member name) + if ispresent && how == IfNotAssigned then resolve_toplevels ts else do + exprs <- eval_exprseq exprseq + case exprs of + Error err -> throwError $ EvalErr line err + _ -> local (Map.insert name exprs) (resolve_toplevels ts) + resolve_toplevels [] = return () + + resolve_block line sels items = do + props <- mapM (resolve_item sels) items + modify (Block line sels (concat props) : ) + + resolve_item _ (Property line name exprseq) = do + exprs <- eval_exprseq exprseq + case exprs of + Error err -> throwError $ EvalErr line err + _ -> return [Property line name [exprs]] + resolve_item sels (SubBlock line subsels items) = + resolve_block line (combine_sels sels subsels) items >> return [] + resolve_item _ (SubGroup _ name items) = mapM (resolve_group name) items + + resolve_group name (Property line prop exprs) = + fmap head $ resolve_item [] (Property line (name ++ "-" ++ prop) exprs) + resolve_group _ _ = error "impossible item in group" + + combine_sels sels subsels = [comb s1 s2 | s1 <- sels, s2 <- subsels] + where comb s1 s2 = maybe (s1 ++ " " ++ s2) + (\i -> (take i s2) ++ s1 ++ (drop (i+1) s2)) + (findIndex (=='&') s2) + + eval_exprseq [] = return $ String "" + eval_exprseq [e] = asks id >>= return . (flip eval e) + eval_exprseq seq = do + varmap <- asks id + return $ findError (Bare . joinShow " ") $ map (eval varmap) seq + + -- evaluate an Expr + eval varmap exp = let eval' = eval varmap in case exp of + Var a -> case Map.lookup a varmap of + Just val -> val + Nothing -> Error $ "variable " ++ a ++ " is not defined" + Plus a b -> case (eval' a, eval' b) of + (String s, String t) -> String (s ++ t) + (Number n, Number m) -> Number (n + m) + (Dim n, Dim m) | Just (n1, m1, w) <- unitconv n m -> Dim (n1 + m1, w) + (Dim (n, u), Number m) -> Dim (n + m, u) + (Number m, Dim (n, u)) -> Dim (m + n, u) + (Color col, Number n) -> Color $ Right $ modifyChannels (+) (rgbColor col) n + (CSSFunc "url" (String url), String s) -> CSSFunc "url" (String $ url ++ s) + (e@(Error _), _) -> e + (_, e@(Error _)) -> e + (x, y) -> Error ("cannot add " ++ show x ++ " and " ++ show y) + Minus a b -> case (eval' a, eval' b) of + (Number n, Number m) -> Number (n - m) + (Dim n, Dim m) | Just (n1, m1, w) <- unitconv n m -> Dim (n1 - m1, w) + (Dim (n, u), Number m) -> Dim (n - m, u) + (Number m, Dim (n, u)) -> Dim (m - n, u) + (Color col, Number n) -> Color $ Right $ modifyChannels (-) (rgbColor col) n + (e@(Error _), _) -> e + (_, e@(Error _)) -> e + (x, y) -> Error ("cannot subtract " ++ show x ++ " and " ++ show y) + Mul a b -> case (eval' a, eval' b) of + (String s, Number n) -> String $ concat (replicate (floor n) s) + (Number n, String s) -> String $ concat (replicate (floor n) s) + (Number n, Number m) -> Number (n * m) + (Dim (n, u), Number m) -> Dim (n * m, u) + (Number m, Dim (n, u)) -> Dim (m * n, u) + (e@(Error _), _) -> e + (_, e@(Error _)) -> e + (x, y) -> Error ("cannot multiply " ++ show x ++ " and " ++ show y) + Divide a b -> case (eval' a, eval' b) of + (Number n, Number m) -> case m of + 0 -> Error "divide by zero" + m -> Number (n / m) + (Dim (n, u), Number m) -> case m of + 0 -> Error "divide by zero" + m -> Dim (n / m, u) + (e@(Error _), _) -> e + (_, e@(Error _)) -> e + (x, y) -> Error ("cannot divide " ++ show x ++ " by " ++ show y) + Modulo a b -> case (eval' a, eval' b) of + (Number n, Number m) -> case m of + 0 -> Error "modulo by zero" + m -> Number (n `ratMod` m) + (Dim (n, u), Number m) -> case m of + 0 -> Error "modulo by zero" + m -> Dim (n `ratMod` m, u) + (e@(Error _), _) -> e + (_, e@(Error _)) -> e + (x, y) -> Error ("cannot calculate modulus of " ++ show x ++ " and " ++ show y) + ExprListCons a b -> case (eval' a, eval' b) of + (_, e@(Error _)) -> e + (e@(Error _), _) -> e + (e, ExprList es) -> ExprList (e:es) + (e1, e2) -> ExprList [e1, e2] + Subseq es -> findError Subseq (map eval' es) + CSSFunc name args -> case (name, eval' args) of + ("url", String url) -> CSSFunc "url" (String url) + ("attr", args) -> CSSFunc "attr" args + ("counter", args) -> CSSFunc "counter" args + (name, args) -> Error $ printf "invalid CSS function: %s(%s)" name (show args) + Call exp name arg -> case (name, eval' exp, fmap eval' arg) of + (_, e@(Error _), _) -> e + (_, _, Just e@(Error _)) -> e + -- String methods + ("bare", String s, Nothing) -> Bare s + ("string", String s, Nothing) -> String s + ("string", v, Nothing) -> String (show v) + ("length", String s, Nothing) -> Number $ toRational (length s) + ("upper", String s, Nothing) -> String (map toUpper s) + ("lower", String s, Nothing) -> String (map toLower s) + ("strip", String s, Nothing) -> String (trim s) + ("split", String s, Just (String delim)) -> + ExprList (map String (split delim s)) + ("eval", String s, Nothing) -> evaluate varmap "evaled string" s + -- Number methods + ("round", Number n, Just (Number p)) -> Number (roundRat n p) + ("round", Number n, Nothing) -> Number (roundRat n 0) + ("round", Dim (n, u), Just (Number p)) -> Dim (roundRat n p, u) + ("round", Dim (n, u), Nothing) -> Dim (roundRat n 0, u) + ("abs", Number n, Nothing) -> Number (abs n) + ("abs", Dim (n, u), Nothing) -> Dim (abs n, u) + -- List and sequence methods + ("length", ExprList l, Nothing) -> Number $ toRational (length l) + ("length", Subseq l, Nothing) -> Number $ toRational (length l) + ("join", ExprList l, Nothing) -> String $ joinShow ", " l + ("join", Subseq l, Nothing) -> String $ joinShow " " l + ("join", ExprList l, Just (String delim)) -> String $ joinShow delim l + ("join", Subseq l, Just (String delim)) -> String $ joinShow delim l + ("list", l@(ExprList _), Nothing) -> l + ("list", Subseq l, Nothing) -> ExprList l + ("seq", l@(Subseq _), Nothing) -> l + ("seq", ExprList l, Nothing) -> Subseq l + -- Color methods + ("brighten", Color col, arg) -> + Color $ Right $ brightenColor (rgbColor col) (getAmount arg) + ("darken", Color col, arg) -> + Color $ Right $ darkenColor (rgbColor col) (getAmount arg) + -- All else is invalid + (name, exp, arg) -> + Error $ printf "cannot call method %s(%s) on %s" name (show arg) (show exp) + Rgb r g b -> case (eval' r, eval' g, eval' b) of + (Number r', Number g', Number b') -> Color $ Right (cx r', cx g', cx b') + (Dim (r', "%"), Dim (g', "%"), Dim (b', "%")) -> + Color $ Right (cx (r' * 2.55), cx (g' * 2.55), cx (b' * 2.55)) + _ -> Error "rgb() arguments must be numbers or percentages" + where cx = inrange 0 255 . floor + -- all other cases are primitive + atom -> atom + + -- evaluate a string + evaluate varmap source string = case runParser exprseq [] "" string of + Left err -> Error $ showWithoutPos ("in "++source++":") err + Right [] -> String "" + Right [e] -> eval varmap e + Right seq -> findError Subseq $ map (eval varmap) seq + + -- return either the first Error in xs, or else (cons xs) + findError cons xs = head $ [Error e | Error e <- xs] ++ [cons xs] + + rgbColor = either (colors Map.!) id + + getAmount arg = case arg of + Nothing -> 0.1 + Just (Number am) -> (fromRational am) / 100 + Just (Dim (am, "%")) -> (fromRational am) / 100 + _ -> 0 + +------------------------------------------------------------------------------------------ +-- main conversion function + +format :: [Topl] -> String +format blocks = concatMap format_block blocks where + format_block (Block _ sels props) = + joinStr ", " sels ++ " {\n" ++ unlines (map format_prop props) ++ "}\n\n" + format_block (Import _ exprs) = "@import " ++ joinShow " " exprs ++ ";\n" + format_block (Assign _ _ _ _) = error "remaining assignment in eval result" + format_prop (Property _ name [val]) = " " ++ name ++ ": " ++ show val ++ ";" + format_prop (Property _ _ _) = error "property has not exactly one value" + format_prop _ = error "remaining subitems in block" + +cleverCSSConvert :: SourceName -> String -> [(String, String)] -> Either String String +cleverCSSConvert name input initial_map = + case runParser parser [0] name (preprocess input) of + Left err -> Left $ "Parse error " ++ show err + Right parse -> case translate parse initial_map of + Left evalerr -> Left $ "Evaluation error " ++ show evalerr + Right blocks -> Right $ format (reverse blocks) diff --git a/Text/CSS/CleverCSSUtil.hs b/Text/CSS/CleverCSSUtil.hs new file mode 100644 --- /dev/null +++ b/Text/CSS/CleverCSSUtil.hs @@ -0,0 +1,346 @@ +------------------------------------------------------------------------------------------ +-- CleverCSS in Haskell, (c) 2007 Georg Brandl. Licensed under the BSD license. +-- +-- CCUtil module: utilities. +------------------------------------------------------------------------------------------ + +module Text.CSS.CleverCSSUtil ( + (+++), (+:+), (~>>), varCount, perhaps, + Color, HLSColor, colors, reverse_colors, + hexToColor, brightenColor, darkenColor, modifyChannels, + unitconv, inrange, readNum, readDim, + trim, ltrim, rtrim, split, joinStr, joinShow, + preprocess, hexToString, cssShow, showWithoutPos, + ratMod, roundRat, + ) where + +import Control.Arrow ((&&&)) +import Control.Monad (msum) +import Data.Char +import Data.List hiding (partition) +import Data.Ratio (Ratio, (%), numerator, denominator) +import Numeric (readFloat) +import Text.Printf (printf) +import Text.ParserCombinators.Parsec (choice, count, try, option, GenParser) +import Text.ParserCombinators.Parsec.Error +import qualified Data.Map as Map + +-- Monad combinator helpers + +type P tok = GenParser tok [Int] + +infixl 1 +++, ~>> +infixr 1 +:+ +-- return the concatenation of the actions' result lists +{-# INLINE (+++) #-} +(+++) :: P tok [a] -> P tok [a] -> P tok [a] +x +++ y = do { rx <- x; ry <- y; return $ rx ++ ry } +-- return a cons of the actions' results +{-# INLINE (+:+) #-} +(+:+) :: P tok a -> P tok [a] -> P tok [a] +x +:+ y = do { rx <- x; ry <- y; return $ rx:ry } +-- return the result of the first action +{-# INLINE (~>>) #-} +(~>>) :: P tok a -> P tok b -> P tok a +x ~>> y = do { rx <- x; y; return rx } + +varCount low high p = choice [try $ count x p | x <- [high,high-1..low]] +perhaps c = option "" (count 1 c) + +-- Color types and utilities + +type Color = (Int, Int, Int) -- range 0..255 +type HLSColor = (Double, Double, Double) -- range 0..1 + +-- | Convert HLS to RGB. +hls_to_rgb :: HLSColor -> Color +hls_to_rgb (_, l, 0) = (l', l', l') where l' = round (255 * l) +hls_to_rgb (h, l, s) = + let m2 = if l <= 0.5 then l * (s+1) else l + s - (l*s) + m1 = 2*l - m2 + in (v m1 m2 (h + 1/3), v m1 m2 h, v m1 m2 (h - 1/3)) + where + v m1' m2' hue' = round (255 * (v' m1' m2' hue')) where + v' m1 m2 hue = + let phue = snd $ properFraction (hue + 2) in + if phue < 1/6 then m1 + (m2-m1) * phue * 6 + else if phue < 1/2 then m2 + else if phue < 2/3 then m1 + (m2-m1) * (2/3 - phue) * 6 + else m1 + +-- | Convert RGB to HLS. +rgb_to_hls :: Color -> HLSColor +rgb_to_hls (r', g', b') = + let r = fromIntegral r' / 255 + g = fromIntegral g' / 255 + b = fromIntegral b' / 255 + maxc = max (max r g) b + minc = min (min r g) b + mami = maxc - minc + l = (minc + maxc) / 2 + s = if l <= 0.5 then mami / (maxc+minc) + else mami / (2-maxc-minc) + rc = (maxc-r) / mami + gc = (maxc-g) / mami + bc = (maxc-b) / mami + h' = if r == maxc then bc - gc + else if g == maxc then 2 + rc - bc + else 4 + gc - rc + h = snd $ properFraction (h'/6) + in if minc == maxc then (0.0, l, 0.0) + else (h, l, s) + + +-- | A map of standard color names and their Hex counterparts. +colors = Map.fromList $ map (fst &&& hexToColor . snd) [ + ("aliceblue", "#f0f8ff"), + ("antiquewhite", "#faebd7"), + ("aqua", "#00ffff"), + ("aquamarine", "#7fffd4"), + ("azure", "#f0ffff"), + ("beige", "#f5f5dc"), + ("bisque", "#ffe4c4"), + ("black", "#000000"), + ("blanchedalmond", "#ffebcd"), + ("blue", "#0000ff"), + ("blueviolet", "#8a2be2"), + ("brown", "#a52a2a"), + ("burlywood", "#deb887"), + ("cadetblue", "#5f9ea0"), + ("chartreuse", "#7fff00"), + ("chocolate", "#d2691e"), + ("coral", "#ff7f50"), + ("cornflowerblue", "#6495ed"), + ("cornsilk", "#fff8dc"), + ("crimson", "#dc143c"), + ("cyan", "#00ffff"), + ("darkblue", "#00008b"), + ("darkcyan", "#008b8b"), + ("darkgoldenrod", "#b8860b"), + ("darkgray", "#a9a9a9"), + ("darkgreen", "#006400"), + ("darkkhaki", "#bdb76b"), + ("darkmagenta", "#8b008b"), + ("darkolivegreen", "#556b2f"), + ("darkorange", "#ff8c00"), + ("darkorchid", "#9932cc"), + ("darkred", "#8b0000"), + ("darksalmon", "#e9967a"), + ("darkseagreen", "#8fbc8f"), + ("darkslateblue", "#483d8b"), + ("darkslategray", "#2f4f4f"), + ("darkturquoise", "#00ced1"), + ("darkviolet", "#9400d3"), + ("deeppink", "#ff1493"), + ("deepskyblue", "#00bfff"), + ("dimgray", "#696969"), + ("dodgerblue", "#1e90ff"), + ("firebrick", "#b22222"), + ("floralwhite", "#fffaf0"), + ("forestgreen", "#228b22"), + ("fuchsia", "#ff00ff"), + ("gainsboro", "#dcdcdc"), + ("ghostwhite", "#f8f8ff"), + ("gold", "#ffd700"), + ("goldenrod", "#daa520"), + ("gray", "#808080"), + ("green", "#008000"), + ("greenyellow", "#adff2f"), + ("honeydew", "#f0fff0"), + ("hotpink", "#ff69b4"), + ("indianred", "#cd5c5c"), + ("indigo", "#4b0082"), + ("ivory", "#fffff0"), + ("khaki", "#f0e68c"), + ("lavender", "#e6e6fa"), + ("lavenderblush", "#fff0f5"), + ("lawngreen", "#7cfc00"), + ("lemonchiffon", "#fffacd"), + ("lightblue", "#add8e6"), + ("lightcoral", "#f08080"), + ("lightcyan", "#e0ffff"), + ("lightgoldenrodyellow", "#fafad2"), + ("lightgreen", "#90ee90"), + ("lightgrey", "#d3d3d3"), + ("lightpink", "#ffb6c1"), + ("lightsalmon", "#ffa07a"), + ("lightseagreen", "#20b2aa"), + ("lightskyblue", "#87cefa"), + ("lightslategray", "#778899"), + ("lightsteelblue", "#b0c4de"), + ("lightyellow", "#ffffe0"), + ("lime", "#00ff00"), + ("limegreen", "#32cd32"), + ("linen", "#faf0e6"), + ("magenta", "#ff00ff"), + ("maroon", "#800000"), + ("mediumaquamarine", "#66cdaa"), + ("mediumblue", "#0000cd"), + ("mediumorchid", "#ba55d3"), + ("mediumpurple", "#9370db"), + ("mediumseagreen", "#3cb371"), + ("mediumslateblue", "#7b68ee"), + ("mediumspringgreen", "#00fa9a"), + ("mediumturquoise", "#48d1cc"), + ("mediumvioletred", "#c71585"), + ("midnightblue", "#191970"), + ("mintcream", "#f5fffa"), + ("mistyrose", "#ffe4e1"), + ("moccasin", "#ffe4b5"), + ("navajowhite", "#ffdead"), + ("navy", "#000080"), + ("oldlace", "#fdf5e6"), + ("olive", "#808000"), + ("olivedrab", "#6b8e23"), + ("orange", "#ffa500"), + ("orangered", "#ff4500"), + ("orchid", "#da70d6"), + ("palegoldenrod", "#eee8aa"), + ("palegreen", "#98fb98"), + ("paleturquoise", "#afeeee"), + ("palevioletred", "#db7093"), + ("papayawhip", "#ffefd5"), + ("peachpuff", "#ffdab9"), + ("peru", "#cd853f"), + ("pink", "#ffc0cb"), + ("plum", "#dda0dd"), + ("powderblue", "#b0e0e6"), + ("purple", "#800080"), + ("red", "#ff0000"), + ("rosybrown", "#bc8f8f"), + ("royalblue", "#4169e1"), + ("saddlebrown", "#8b4513"), + ("salmon", "#fa8072"), + ("sandybrown", "#f4a460"), + ("seagreen", "#2e8b57"), + ("seashell", "#fff5ee"), + ("sienna", "#a0522d"), + ("silver", "#c0c0c0"), + ("skyblue", "#87ceeb"), + ("slateblue", "#6a5acd"), + ("slategray", "#708090"), + ("snow", "#fffafa"), + ("springgreen", "#00ff7f"), + ("steelblue", "#4682b4"), + ("tan", "#d2b48c"), + ("teal", "#008080"), + ("thistle", "#d8bfd8"), + ("tomato", "#ff6347"), + ("turquoise", "#40e0d0"), + ("violet", "#ee82ee"), + ("wheat", "#f5deb3"), + ("white", "#ffffff"), + ("whitesmoke", "#f5f5f5"), + ("yellow", "#ffff00"), + ("yellowgreen", "#9acd32")] + +reverse_colors = Map.fromList $ map (snd &&& fst) $ (Map.toList colors) + +hexToColor [h1,h2,h3,h4,h5,h6] = (hx [h1,h2], hx [h3,h4], hx [h5,h6]) + where hx x = read ("0x" ++ x) :: Int +hexToColor [h1,h2,h3] = hexToColor [h1,h1,h2,h2,h3,h3] +hexToColor ('#':hs) = hexToColor hs +hexToColor _ = error "invalid hex color string" + +brightenColor = modifyColor (\l a -> l*(1+a)) +darkenColor = modifyColor (\l a -> l*(1-a)) +modifyColor fun col am = hls_to_rgb (h, inrange 0.0 1.0 (fun l am), s) + where (h, l, s) = rgb_to_hls col + +modifyChannels :: (Rational -> Rational -> Rational) -> (Int, Int, Int) -> + Rational -> (Int, Int, Int) +modifyChannels op (r, g, b) am = (m r, m g, m b) + where m x = inrange 0 255 $ floor $ op (fromInteger (toInteger x)) am + +inrange low high val = min high (max low val) + +-- Unit utilities + +units = [[("mm", 1), ("cm", 10), ("in", 254%10), ("pt", 254%720), ("pc", 254%60)], + [("ms", 1), ("s", 1000)], + [("Hz", 1), ("kHz", 1000)]] + +unitconv :: (Rational, String) -> (Rational, String) -> Maybe (Rational, Rational, String) +unitconv (x, u) (y, v) + | u == v = Just (x, y, v) + | otherwise = msum $ map (ratio u v) units + where ratio u v list = case (lookup u list, lookup v list) of + (Just du, Just dv) -> if du < dv then Just (x, dv/du * y, u) + else Just (du/dv * x, y, v) + _ -> Nothing + +readNum x = case readWithSign 1 x of (sign, res) -> sign * fst res +readDim x = case readWithSign 1 x of + (sign, res) -> (sign * fst res, trim (snd res)) + +readWithSign _ ('-':num) = readWithSign (-1) num +readWithSign sign num = (sign, head (readFloat num :: [(Rational, String)])) + +-- String utilities + +ltrim (c:cs) | c `elem` " \t\v\f\r\n" = ltrim cs +ltrim cs = cs + +rtrim = reverse . ltrim . reverse + +trim = ltrim . rtrim + +preprocess :: String -> String +preprocess [] = ['\n'] -- be sure to have always a newline at the end +preprocess ('\t':xs) = ' ':' ':' ':' ':' ':' ':' ':' ' : preprocess xs +preprocess ('\f':xs) = '\n' : preprocess xs +preprocess ('\r':xs) = preprocess xs +preprocess (x:xs) = x : preprocess xs + +spanList :: ([a] -> Bool) -> [a] -> ([a], [a]) +spanList _ [] = ([],[]) +spanList func list@(x:xs) = + if func list + then (x:ys,zs) + else ([],list) + where (ys,zs) = spanList func xs + +breakList :: ([a] -> Bool) -> [a] -> ([a], [a]) +breakList func = spanList (not . func) + +split :: String -> String -> [String] +split _ [] = [] +split delim str = + let (firstline, remainder) = breakList (isPrefixOf delim) str in + firstline : case remainder of + [] -> [] + x -> if x == delim then [] : [] + else split delim (drop (length delim) x) + +{-# INLINE joinStr #-} +joinStr d x = concat (intersperse d x) +{-# INLINE joinShow #-} +joinShow d x = joinStr d (map show x) + +hexToString :: String -> Char +hexToString x = toEnum (read $ "0x" ++ x) + +cssShow s = '"':cssShow' s where + cssShow' ('"':cs) = '\\':'"':cssShow' cs + cssShow' (c:cs) | c `elem` [' '..'~'] = c:cssShow' cs + | otherwise = printf "\\%x " (fromEnum c) ++ cssShow' cs + cssShow' [] = ['"'] + +-- show a Parsec error without position, but with an additional message +showWithoutPos msg err = msg ++ showErrorMessages "or" "unknown parse error" + "expecting" "unexpected" "end of input" (errorMessages err) + +-- Ratio arithmetic + +ratMod :: Rational -> Rational -> Rational +ratMod x y = (nx `mod` ny) % d where + dx = denominator x + dy = denominator y + d = lcm dx dy + nx = numerator x * (d `div` dx) + ny = numerator y * (d `div` dy) + +roundRat :: Rational -> Rational -> Rational +roundRat num places = + let exp = round places :: Integer in + (round (num * (10^exp))) % (10^exp) -- XXX todo diff --git a/clevercss.cabal b/clevercss.cabal new file mode 100644 --- /dev/null +++ b/clevercss.cabal @@ -0,0 +1,21 @@ +Name: clevercss +Version: 0.1 +Category: Text +Synopsis: A CSS preprocessor +Description: CleverCSS is a CSS preprocessing library that allows defining variables and nesting selectors so that you don't need to Repeat Yourself. +License: BSD3 +License-File: LICENSE +Author: Georg Brandl +Maintainer: georg@python.org +Homepage: http://sandbox.pocoo.org/clevercss-hs/ +Stability: experimental +Build-Depends: base, parsec, mtl, haskell98 +Extra-Source-Files: documentation.html, example.ccs +Extensions: PatternGuards +GHC-Options: -O1 -funbox-strict-fields +Exposed-Modules: Text.CSS.CleverCSS +Other-Modules: Text.CSS.CleverCSSUtil + +Executable: clevercss +Main-is: CCMain.hs + diff --git a/documentation.html b/documentation.html new file mode 100644 --- /dev/null +++ b/documentation.html @@ -0,0 +1,450 @@ + + + + + + +CleverCSS (Haskell) Documentation + + + +
+

CleverCSS (Haskell) Documentation

+
+

Introduction

+

CleverCSS is a system for writing templates that are translated into CSS, +allowing to build style sheets in a clean and structured way, following the DRY +(don't repeat yourself) principle.

+

The syntax is slightly different from CSS in that it relies on indentation +instead of braces to indicate grouping, like the Python language does.

+

The two things that enable DRY are variables and nesting. Variables are +names for CSS values; nesting prevents repeating selectors all over. Here is an +example template file:

+
+bgcolor = #f0f0e4
+
+ul#comments, ol#comments:
+   background-color: $bgcolor
+
+   li:
+      background-color: $bgcolor
+      font-size: 1.2em
+
+

It would translate to (an equivalent of) this CSS stylesheet:

+
+ul#comments, ol#comments {
+   background-color: #f0f0e4;
+}
+
+ul#comments li, ol#comments li {
+   background-color: #f0f0e4;
+   font-size: 1.2em;
+}
+
+

You can already see that the template doesn't repeat the ul#comments and +ol#comments selectors. Also, should the desired background color ever +change, you won't need to replace a zillion references to it, but only one +variable assignment.

+

Other than that, CleverCSS allows expressions involving CSS values as well as +grouping of similar property names, as shown below.

+
+
+

Syntax

+

As you have already seen, you use indentation and colons to express grouping. +There are also other small syntactic differences to CSS that make writing +templates less pain:

+
    +
  • Semicolons at line ends are optional.
    • +
  • There are no /* ... */ multiline comments, but Java-style // line +comments.
    • +
  • A line consisting only of __END__ means "end of template". Everything +after that line is completely ignored by CleverCSS.
    • +
+
+
+

Constructs

+
+

Variable assignments

+

You can assign to variables with an equals sign. Variable assignments are not +allowed inside blocks, only at the toplevel. Variables can be assigned to +multiple times.

+
+foo = 1px
+body:
+   margin: $foo
+foo = 2px
+p:
+   margin: $foo
+
+

would result in body { margin: 1px } and p { margin: 2px }. Referencing +variables before they are defined is an error.

+

There's also another assignment operator, ?=. It only has an effect if the +variable is not assigned to yet. This is helpful to provide defaults that can +be overridden by e.g. command line definitions. For example, after

+
+foo = 1px
+bar = 1px
+foo = 2px
+bar ?= 2px
+
+

$foo would be replaced by 2px, while $bar would be replaced by +1px.

+
+
+

Selectors

+

CleverCSS does not process selectors in a special way, but as shown above you +can nest selector blocks instead of repeating parent selectors in individual +blocks:

+
+ul, ol:
+   foo
+   li, p:
+      bar
+      strong, em:
+         baz
+
+

would result in

+
+ul, ol { foo }
+
+ul li, ul p, ol li, ol p { bar }
+
+ul li strong, ul li em, ul p strong, ul p em,
+ol li strong, ol li em, ol p strong, ol p em  { baz }
+
+

To achieve this, the selectors are currently bluntly split at commas, so +extended selectors involving string matching with a comma will be handled +incorrectly at the moment.

+

As you see, the above handles basic parent-child relations by joining parent and +child selectors with a space. However, you can also explicitly determine where +to put the parent selector, using the & character:

+
+strong, em:
+   a &, #&:
+      bar
+
+

would result in

+
+a strong, #strong, a em, #em { bar }
+
+

Using this technique, you can construct selectors quite freely. Multiple +occurrences of the ampersand are replaced.

+
+
+

Properties

+

Property specifications work like in CSS: just put a colon after the property +name. You can use expressions or variable references (see below) only in +property values, not in property names.

+
+
+

Property groups

+

Since CSS has many property names with common prefixes, CleverCSS includes one +more shortening notation, best described by an example:

+
+#main p:
+   font->
+      family: Verdana, sans-serif
+      size: 1.1em
+      style: italic
+
+

would result in

+
+#main p {
+   font-family: Verdana, sans-serif;
+   font-size: 1.1em;
+   font-style: italic;
+}
+
+

The -> symbol, followed by a block of properties, concatenates the name +before it with each of the property names in the block.

+
+
+
+

Values and expressions

+

CleverCSS property values are of multiple types which also exist in CSS:

+ +++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
TypeExample propertyNote
barewords (also called identifiers)font-size: small 
strings (double or single quoted)font-family: "Times" 
numbers (integral or floating)line-height: 2 
dimensions (number + unit)margin-left: 2px 
hexadecimal colorscolor: #f0f0f0 
colors as color namescolor: black(1)
colors via the RGB functioncolor: rgb(10%, 20%, 30%) 
value sequences (separated by whitespace)margin: 2px 0 2px 0 
value lists (separated by commas)font-family: "Times", serif(2)
function callscontent: attr(id)(3)
+

Notes:

+
    +
  1. Color names are also valid identifiers. CleverCSS recognizes the 140 common +Netscape color names and treats them as values of type color, but does not +convert them to RGB format until you do arithmetic with them. That way, you +can have barewords that are color names without a problem.
    2. +
  2. This is only used in CSS for the font-family property, but you are free +to use value lists anywhere and convert them to other values using their +methods, see below.
    3. +
  3. The functions recognized by CleverCSS, in addition to rgb, are attr, +counter and url.
    4. +
+

CleverCSS extends CSS in that it allows writing not only these literal values, +but also expressions involving these values. These expressions can contain +these elements, in addition to the literal expressions described above:

+ +++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
TypeExample(s)Note
Arithmetic on numbers and values; +operators are +, -, *, / +and % (modulo)4 % 3 = 1, 2px + 4px = 6px, +2 * 2px = 4px(1)
Arithmetic on colors with + and -#f0f000 + #000030 = #f0f030, +#808080 + 16 = #909090(2)
Concatenation of strings with +"hello " + "world" = "hello world"(3)
String multiplication"a " * 3 = "a a a " 
Expression grouping with parentheses(2 + 3) * 5px 
Method calls#303030.brighten(40%) = #434343, +"hello".bare() = hello(4)
Variable references$foo = <whatever foo was assigned> 
+

More explanations:

+
    +

  1. Arithmetic on numbers works as expected.

    +

    You can mix one number and one value in arithmetic expressions, the result +will automatically be given the unit of the value. This is natural with +multiplication and division but can feel weird with addition and subtraction.

    +

    You can add and subtract two dimensions provided their units are the same or +convertable to one another, but you cannot multiply or divide them.

    +
    2. +

  2. If two colors are added or subtracted, their individual channels will be +added or subtracted. If one operand is a number, it will be applied to all +channels.

    +
    3. +

  3. Barewords cannot be added, but you can convert strings to barewords with the +bare() method afterwards.

    +
    4. +

  4. For a list of available methods, see below.

    +
    5. +
+
+

Methods

+

On values of all types:

+
    +
  • string(): convert to a string.
    • +
+

On strings:

+
    +
  • bare(): convert the string to a bareword. It is not checked that it has the +required format!
    • +
  • length(): return the string's length.
    • +
  • upper(), lower(): convert the string to uppercase/lowercase.
    • +
  • strip(): return the string with all trailing and leading whitespace removed.
    • +
  • split(delim): return a list with substrings, split at the string delim.
    • +
  • eval(): evaluate the contents as a CleverCSS expression and return the result.
    • +
+

On numbers and dimensions:

+
    +
  • round([places]): return the number or dimension rounded to places decimal +places; places defaults to 0.
    • +
  • abs(): return the absolute value.
    • +
+

On colors:

+
    +
  • brighten([amount]): return the color brightened by the specified amount, +which should be a percent dimension. amount defaults to 10%.
    • +
  • darken([amount]): return the color darkened by the specified amount, which +should be a percent dimension. amount defaults to 10%.
    • +
+

On lists and sequences:

+
    +
  • length(): return the list or sequence's length.
    • +
  • join([delim]): return a string consisting the items converted to strings +and joined by delim, which defaults to ", " for lists and " " for +sequences.
    • +
  • list(): return the sequence as a list, or the list unchanged.
    • +
  • seq(): return the list as a sequence, or the sequence unchanged.
    • +
+
+
+
+

Library usage

+

Using the CleverCSS library is straightforward, just import Text.CSS.CleverCSS +and use the cleverCSSConvert function, which is defined as

+
+cleverCSSConvert :: SourceName -> String -> [(String, String)] -> Either String String
+
+

The arguments are:

+
    +
  • name of input (normally file name, only used for error messages)
    • +
  • input template
    • +
  • initial variable assignments as (name, value) pairs; the value is evaluated +as a CleverCSS expression when used
    • +
+

The return value is either Left errormessage or Right stylesheet.

+
+
+

Command-line usage

+

CleverCSS also can be compiled as a standalone command-line program. It can be +called with no arguments, in which case it will convert standard input to +standard output, or with file names as arguments, in which case it will convert +the files named to CSS and store them in a file with the same name, but the +extension replaced with .css (e.g., example.clevercss is converted to +example.css).

+

You can use the -D name=value command line option to assign initial +variables. The value is evaluated as a CleverCSS expression when used.

+
+
+

How to get and install it

+

CleverCSS can be downloaded from +Hackage +or checked out from Mercurial at <http://dev.pocoo.org/hg/clevercss-hs-main>. +It is a cabalized package, so the usual

+
+runhaskell Setup.lhs configure
+runhaskell Setup.lhs build
+sudo runhaskell Setup.lhs install
+
+

should be enough to get the clevercss binary and the Text.CSS.CleverCSS +library installed.

+
+
+

Authors

+

The Haskell CleverCSS library is written by Georg Brandl <georg@python.org>. +Bug reports and suggestions are welcome!

+

The CleverCSS template language was initially devised and implemented in Python +by Armin Ronacher, see <http://sandbox.pocoo.org/clevercss>.

+
+
+ + diff --git a/example.ccs b/example.ccs new file mode 100644 --- /dev/null +++ b/example.ccs @@ -0,0 +1,55 @@ +// This is an example CleverCSS template file. + +base_url = "http://www.example.com" +base_padding = 20px +background_color = #eee // this is a comment +text_color = #111 +link_color = #ff0000 + +@import url($base_url + "/styles.css"); + +body: + font-family: 'Verdana', 'Times New Roman', serif + color: $text_color + padding-> + top: $base_padding + 2 + right: $base_padding + 3 + left: $base_padding + 3 + bottom: $base_padding + 2 + margin: $supply_me_in_default_variables + background-color: $background_color + +div.foo: + width: "Hello World".length() * 20px + foo: (foo, bar, baz, 42).join('/') + +a, b: + color: $link_color + &:hover, &:link: + color: $link_color.darken(30%) + &:active: + color: $link_color.brighten(10%) + +base_padding = $base_padding + 4px; + +div.navigation: + height: 1.2em; + padding: 0.2cm + 1mm; + color: rgb(40, 50, 7 * 24) // this is a comment too + background-color: #606060.brighten(30%) + ul: + margin: 0 + padding: $base_padding + list-style: none + li: + float: left + height: 1.2em + a, strong, em: + display: block + height: 1em + padding: 0.1em + foo: (1 2 3).join("-").bare() + +__END__ + +This is completely ignored by CleverCSS.