diff options
Diffstat (limited to 'Utility/Format.hs')
| -rw-r--r-- | Utility/Format.hs | 46 |
1 files changed, 31 insertions, 15 deletions
diff --git a/Utility/Format.hs b/Utility/Format.hs index a2470fa..466988c 100644 --- a/Utility/Format.hs +++ b/Utility/Format.hs @@ -1,6 +1,6 @@ {- Formatted string handling. - - - Copyright 2010, 2011 Joey Hess <id@joeyh.name> + - Copyright 2010-2020 Joey Hess <id@joeyh.name> - - License: BSD-2-clause -} @@ -9,8 +9,10 @@ module Utility.Format ( Format, gen, format, + formatContainsVar, decode_c, encode_c, + encode_c', prop_encode_c_decode_c_roundtrip ) where @@ -29,9 +31,14 @@ type FormatString = String {- A format consists of a list of fragments. -} type Format = [Frag] -{- A fragment is either a constant string, - - or a variable, with a justification. -} -data Frag = Const String | Var String Justify +{- A fragment is either a constant string, or a variable. -} +data Frag + = Const String + | Var + { varName :: String + , varJustify :: Justify + , varEscaped :: Bool + } deriving (Show) data Justify = LeftJustified Int | RightJustified Int | UnJustified @@ -45,10 +52,8 @@ format :: Format -> Variables -> String format f vars = concatMap expand f where expand (Const s) = s - expand (Var name j) - | "escaped_" `isPrefixOf` name = - justify j $ encode_c_strict $ - getvar $ drop (length "escaped_") name + expand (Var name j esc) + | esc = justify j $ encode_c' isSpace $ getvar name | otherwise = justify j $ getvar name getvar name = fromMaybe "" $ M.lookup name vars justify UnJustified s = s @@ -61,6 +66,8 @@ format f vars = concatMap expand f - format string, such as "${foo} ${bar;10} ${baz;-10}\n" - - (This is the same type of format string used by dpkg-query.) + - + - Also, "${escaped_foo}" will apply encode_c to the value of variable foo. -} gen :: FormatString -> Format gen = filter (not . empty) . fuse [] . scan [] . decode_c @@ -94,12 +101,24 @@ gen = filter (not . empty) . fuse [] . scan [] . decode_c | i < 0 = LeftJustified (-1 * i) | otherwise = RightJustified i novar v = "${" ++ reverse v - foundvar f v p = scan (Var (reverse v) p : f) + foundvar f varname_r p = + let varname = reverse varname_r + var = if "escaped_" `isPrefixOf` varname + then Var (drop (length "escaped_") varname) p True + else Var varname p False + in scan (var : f) empty :: Frag -> Bool empty (Const "") = True empty _ = False +{- Check if a Format contains a variable with a specified name. -} +formatContainsVar :: String -> Format -> Bool +formatContainsVar v = any go + where + go (Var v' _ _) | v' == v = True + go _ = False + {- Decodes a C-style encoding, where \n is a newline (etc), - \NNN is an octal encoded character, and \xNN is a hex encoded character. -} @@ -144,10 +163,7 @@ decode_c s = unescape ("", s) encode_c :: String -> FormatString encode_c = encode_c' (const False) -{- Encodes more strictly, including whitespace. -} -encode_c_strict :: String -> FormatString -encode_c_strict = encode_c' isSpace - +{- Encodes special characters, as well as any matching the predicate. -} encode_c' :: (Char -> Bool) -> String -> FormatString encode_c' p = concatMap echar where @@ -165,8 +181,8 @@ encode_c' p = concatMap echar | ord c < 0x20 = e_asc c -- low ascii | ord c >= 256 = e_utf c -- unicode | ord c > 0x7E = e_asc c -- high ascii - | p c = e_asc c -- unprintable ascii - | otherwise = [c] -- printable ascii + | p c = e_asc c + | otherwise = [c] -- unicode character is decomposed to individual Word8s, -- and each is shown in octal e_utf c = showoctal =<< (Codec.Binary.UTF8.String.encode [c] :: [Word8]) |