/[james]/factorcss/FactorCSS.hs
ViewVC logotype

Diff of /factorcss/FactorCSS.hs

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 62 by james, Mon Dec 27 19:11:07 2004 UTC revision 66 by james, Thu Dec 30 21:22:59 2004 UTC
# Line 1  Line 1 
1  -- Factor a CSS stylesheet  --
2    -- This file is part of FactorCSS
3    -- Licensed under the MIT License,
4    --                http://www.opensource.org/licenses/mit-license
5    -- Copyright 2004 James Bursa <james@semichrome.net>
6    --
7    
8    -- Factor a CSS stylesheet.
9    --
10    -- This tool takes a CSS stylesheet on input and produces an almost equivalent
11    -- stylesheet on output, but with rulesets split, combined, and reordered to
12    -- "factor out" common declarations. This helps reveal shared components. The
13    -- resulting stylesheet may also be smaller.
14    --
15    -- The only known case where the output is not equivalent to the input is when
16    -- the stylesheet depends on the order of rules (see CSS 2.1 6.4.1).
17    
18  import List  import List
19    import System
20  import Tokeniser  import Tokeniser
21  import Parser  import Parser
22  import CSS  import CSS
23    
24    -- Program entry function.
25    main :: IO ()
26  main = do  main = do
27          s <- getContents          args <- getArgs
28  --      print (alexScanTokens s)          interact (run args)
29  --      (print . process . parser . alexScanTokens) s  
30          (putStr . unlines . show_stylesheet . process .  -- Produce output from arguments and input.
31                          parser . alexScanTokens) s  run :: [String] -> String -> String
32    run args input
33            | argument "help" args          = usage
34            | null args                     = go factor
35            | argument "factor" args        = go factor
36            | argument "explode" args       = go (concatMap explode)
37            | otherwise                     = usage
38            where   go f = (unlines . show_stylesheet . process f .
39                                    parser . alexScanTokens) input
40    
41    -- Check an argument list for an argument in short or long form.
42    argument :: String -> [String] -> Bool
43    argument long args = elem short shorts || elem ("--" ++ long) args
44                    where   short = head long
45                            shorts = (concat . filter is_short) args
46                            is_short ('-':'-':_) = False
47                            is_short ('-':_) = True
48                            is_short _ = False
49    
50    -- Usage help string.
51    usage :: String
52    usage = unlines ["Usage: factorcss [OPTION]... <FILE",
53                    "\"Factor out\" common declarations in a CSS stylesheet by splitting, reordering,",
54                    "and combining rulesets.",
55                    "The stylesheet is read from standard input, and the result is produced on",
56                    "standard output.",
57                    "",
58                    "Output mode:",
59                    "  -f, --factor   factor out common declarations (default)",
60                    "  -e, --explode  produce rulesets with one selector and declaration each",
61                    "",
62                    "  -h, --help     display this help and exit"]
63    
64  -- Process a Stylesheet.  -- Process a Stylesheet.
65  process :: Stylesheet -> Stylesheet  process :: ([Statement] -> [Statement]) -> Stylesheet -> Stylesheet
66  process (Stylesheet charset imports stmts) =  process f (Stylesheet charset imports stmts) =
67                  Stylesheet charset imports (process_stmts stmts)                  Stylesheet charset imports (process_stmts f stmts)
68    
69  -- Process a list of Statements.  -- Process a list of Statements.
70  process_stmts :: [Statement] -> [Statement]  process_stmts :: ([Statement] -> [Statement]) -> [Statement] -> [Statement]
71  process_stmts stmts = (factor . filter is_ruleset) stmts ++  process_stmts f stmts = (f . filter is_ruleset) stmts ++
72                  (map process_media . filter is_media) stmts ++                  (map (process_media f) . filter is_media) stmts ++
73                  filter is_page stmts                  filter is_page stmts
74    
75  -- Process a Media Statement.  -- Process a Media Statement.
76  process_media :: Statement -> Statement  process_media :: ([Statement] -> [Statement]) -> Statement -> Statement
77  process_media (Media media stmts) = Media media (factor stmts)  process_media f (Media media stmts) = Media media (f stmts)
78    
79  -- Factor a list of Ruleset Statements.  -- Factor a list of Ruleset Statements.
80  factor :: [Statement] -> [Statement]  factor :: [Statement] -> [Statement]
# Line 72  cmp_decl (Ruleset sels0 (decl0:decls0)) Line 121  cmp_decl (Ruleset sels0 (decl0:decls0))
121  eq_sel :: Statement -> Statement -> Bool  eq_sel :: Statement -> Statement -> Bool
122  eq_sel z = (== EQ) . cmp_sel z  eq_sel z = (== EQ) . cmp_sel z
123    
124  -- Compare two Ruleset Statements for equality by the first declaration in each.  -- Compare two Ruleset Statements for equality by the first declaration in
125    -- each.
126  eq_decl :: Statement -> Statement -> Bool  eq_decl :: Statement -> Statement -> Bool
127  eq_decl z = (== EQ) . cmp_decl z  eq_decl z = (== EQ) . cmp_decl z
128    
Legend:
Removed from v.62  
changed lines
  Added in v.66
  ViewVC Help
Powered by ViewVC 1.1.26