hledger/hledger-lib/Hledger/Utils/String.hs
2015-08-19 20:53:50 -07:00

228 lines
7.4 KiB
Haskell

module Hledger.Utils.String (
-- * misc
lowercase,
uppercase,
underline,
stripbrackets,
unbracket,
-- quoting
quoteIfSpaced,
quoteIfNeeded,
singleQuoteIfNeeded,
-- quotechars,
-- whitespacechars,
escapeDoubleQuotes,
escapeSingleQuotes,
escapeQuotes,
words',
unwords',
stripquotes,
isSingleQuoted,
isDoubleQuoted,
-- * single-line layout
strip,
lstrip,
rstrip,
chomp,
elideLeft,
elideRight,
-- * multi-line layout
concatTopPadded,
concatBottomPadded,
vConcatRightAligned,
padtop,
padbottom,
padleft,
padright,
cliptopleft,
fitto
) where
import Data.Char
import Data.List
import Text.Parsec
import Text.Printf
import Hledger.Utils.Parse
import Hledger.Utils.Regex
lowercase, uppercase :: String -> String
lowercase = map toLower
uppercase = map toUpper
-- | Remove leading and trailing whitespace.
strip :: String -> String
strip = lstrip . rstrip
-- | Remove leading whitespace.
lstrip :: String -> String
lstrip = dropWhile (`elem` " \t") :: String -> String -- XXX isSpace ?
-- | Remove trailing whitespace.
rstrip :: String -> String
rstrip = reverse . lstrip . reverse
-- | Remove trailing newlines/carriage returns.
chomp :: String -> String
chomp = reverse . dropWhile (`elem` "\r\n") . reverse
stripbrackets :: String -> String
stripbrackets = dropWhile (`elem` "([") . reverse . dropWhile (`elem` "])") . reverse :: String -> String
elideLeft :: Int -> String -> String
elideLeft width s =
if length s > width then ".." ++ reverse (take (width - 2) $ reverse s) else s
elideRight :: Int -> String -> String
elideRight width s =
if length s > width then take (width - 2) s ++ ".." else s
underline :: String -> String
underline s = s' ++ replicate (length s) '-' ++ "\n"
where s'
| last s == '\n' = s
| otherwise = s ++ "\n"
-- | Wrap a string in double quotes, and \-prefix any embedded single
-- quotes, if it contains whitespace and is not already single- or
-- double-quoted.
quoteIfSpaced :: String -> String
quoteIfSpaced s | isSingleQuoted s || isDoubleQuoted s = s
| not $ any (`elem` s) whitespacechars = s
| otherwise = "'"++escapeSingleQuotes s++"'"
-- | Double-quote this string if it contains whitespace, single quotes
-- or double-quotes, escaping the quotes as needed.
quoteIfNeeded :: String -> String
quoteIfNeeded s | any (`elem` s) (quotechars++whitespacechars) = "\"" ++ escapeDoubleQuotes s ++ "\""
| otherwise = s
-- | Single-quote this string if it contains whitespace or double-quotes.
-- No good for strings containing single quotes.
singleQuoteIfNeeded :: String -> String
singleQuoteIfNeeded s | any (`elem` s) whitespacechars = "'"++s++"'"
| otherwise = s
quotechars, whitespacechars :: [Char]
quotechars = "'\""
whitespacechars = " \t\n\r"
escapeDoubleQuotes :: String -> String
escapeDoubleQuotes = regexReplace "\"" "\""
escapeSingleQuotes :: String -> String
escapeSingleQuotes = regexReplace "'" "\'"
escapeQuotes :: String -> String
escapeQuotes = regexReplace "([\"'])" "\\1"
-- | Quote-aware version of words - don't split on spaces which are inside quotes.
-- NB correctly handles "a'b" but not "''a''". Can raise an error if parsing fails.
words' :: String -> [String]
words' "" = []
words' s = map stripquotes $ fromparse $ parsewith p s
where
p = do ss <- (singleQuotedPattern <|> doubleQuotedPattern <|> pattern) `sepBy` many1 spacenonewline
-- eof
return ss
pattern = many (noneOf whitespacechars)
singleQuotedPattern = between (char '\'') (char '\'') (many $ noneOf "'")
doubleQuotedPattern = between (char '"') (char '"') (many $ noneOf "\"")
-- | Quote-aware version of unwords - single-quote strings which contain whitespace
unwords' :: [String] -> String
unwords' = unwords . map quoteIfNeeded
-- | Strip one matching pair of single or double quotes on the ends of a string.
stripquotes :: String -> String
stripquotes s = if isSingleQuoted s || isDoubleQuoted s then init $ tail s else s
isSingleQuoted s@(_:_:_) = head s == '\'' && last s == '\''
isSingleQuoted _ = False
isDoubleQuoted s@(_:_:_) = head s == '"' && last s == '"'
isDoubleQuoted _ = False
unbracket :: String -> String
unbracket s
| (head s == '[' && last s == ']') || (head s == '(' && last s == ')') = init $ tail s
| otherwise = s
-- | Join multi-line strings as side-by-side rectangular strings of the same height, top-padded.
concatTopPadded :: [String] -> String
concatTopPadded strs = intercalate "\n" $ map concat $ transpose padded
where
lss = map lines strs
h = maximum $ map length lss
ypad ls = replicate (difforzero h (length ls)) "" ++ ls
xpad ls = map (padleft w) ls where w | null ls = 0
| otherwise = maximum $ map length ls
padded = map (xpad . ypad) lss
-- | Join multi-line strings as side-by-side rectangular strings of the same height, bottom-padded.
concatBottomPadded :: [String] -> String
concatBottomPadded strs = intercalate "\n" $ map concat $ transpose padded
where
lss = map lines strs
h = maximum $ map length lss
ypad ls = ls ++ replicate (difforzero h (length ls)) ""
xpad ls = map (padright w) ls where w | null ls = 0
| otherwise = maximum $ map length ls
padded = map (xpad . ypad) lss
-- | Compose strings vertically and right-aligned.
vConcatRightAligned :: [String] -> String
vConcatRightAligned ss = intercalate "\n" $ map showfixedwidth ss
where
showfixedwidth = printf (printf "%%%ds" width)
width = maximum $ map length ss
-- | Convert a multi-line string to a rectangular string top-padded to the specified height.
padtop :: Int -> String -> String
padtop h s = intercalate "\n" xpadded
where
ls = lines s
sh = length ls
sw | null ls = 0
| otherwise = maximum $ map length ls
ypadded = replicate (difforzero h sh) "" ++ ls
xpadded = map (padleft sw) ypadded
-- | Convert a multi-line string to a rectangular string bottom-padded to the specified height.
padbottom :: Int -> String -> String
padbottom h s = intercalate "\n" xpadded
where
ls = lines s
sh = length ls
sw | null ls = 0
| otherwise = maximum $ map length ls
ypadded = ls ++ replicate (difforzero h sh) ""
xpadded = map (padleft sw) ypadded
difforzero :: (Num a, Ord a) => a -> a -> a
difforzero a b = maximum [(a - b), 0]
-- | Convert a multi-line string to a rectangular string left-padded to the specified width.
padleft :: Int -> String -> String
padleft w "" = concat $ replicate w " "
padleft w s = intercalate "\n" $ map (printf (printf "%%%ds" w)) $ lines s
-- | Convert a multi-line string to a rectangular string right-padded to the specified width.
padright :: Int -> String -> String
padright w "" = concat $ replicate w " "
padright w s = intercalate "\n" $ map (printf (printf "%%-%ds" w)) $ lines s
-- | Clip a multi-line string to the specified width and height from the top left.
cliptopleft :: Int -> Int -> String -> String
cliptopleft w h = intercalate "\n" . take h . map (take w) . lines
-- | Clip and pad a multi-line string to fill the specified width and height.
fitto :: Int -> Int -> String -> String
fitto w h s = intercalate "\n" $ take h $ rows ++ repeat blankline
where
rows = map (fit w) $ lines s
fit w = take w . (++ repeat ' ')
blankline = replicate w ' '