Move src/ to lib/, put Init.hs in src/

1 files changed, 78 insertions, 0 deletions

diff --git a/lib/Hakyll/Core/Util/String.hs b/lib/Hakyll/Core/Util/String.hs
new file mode 100644
index 0000000..23bdd39
--- /dev/null
+++ b/lib/Hakyll/Core/Util/String.hs
@@ -0,0 +1,78 @@
+{-# LANGUAGE FlexibleContexts #-}
+--------------------------------------------------------------------------------
+-- | Miscellaneous string manipulation functions.
+module Hakyll.Core.Util.String
+    ( trim
+    , replaceAll
+    , splitAll
+    , needlePrefix
+    ) where
+
+
+--------------------------------------------------------------------------------
+import Data.Char (isSpace)
+import Data.List (isPrefixOf)
+import Data.Maybe (listToMaybe)
+import Text.Regex.TDFA ((=~~))
+
+
+--------------------------------------------------------------------------------
+-- | Trim a string (drop spaces, tabs and newlines at both sides).
+trim :: String -> String
+trim = reverse . trim' . reverse . trim'
+  where
+    trim' = dropWhile isSpace
+
+
+--------------------------------------------------------------------------------
+-- | A simple (but inefficient) regex replace funcion
+replaceAll :: String              -- ^ Pattern
+           -> (String -> String)  -- ^ Replacement (called on capture)
+           -> String              -- ^ Source string
+           -> String              -- ^ Result
+replaceAll pattern f source = replaceAll' source
+  where
+    replaceAll' src = case listToMaybe (src =~~ pattern) of
+        Nothing     -> src
+        Just (o, l) ->
+            let (before, tmp) = splitAt o src
+                (capture, after) = splitAt l tmp
+            in before ++ f capture ++ replaceAll' after
+
+
+--------------------------------------------------------------------------------
+-- | A simple regex split function. The resulting list will contain no empty
+-- strings.
+splitAll :: String    -- ^ Pattern
+         -> String    -- ^ String to split
+         -> [String]  -- ^ Result
+splitAll pattern = filter (not . null) . splitAll'
+  where
+    splitAll' src = case listToMaybe (src =~~ pattern) of
+        Nothing     -> [src]
+        Just (o, l) ->
+            let (before, tmp) = splitAt o src
+            in before : splitAll' (drop l tmp)
+
+
+
+--------------------------------------------------------------------------------
+-- | Find the first instance of needle (must be non-empty) in haystack. We
+-- return the prefix of haystack before needle is matched.
+--
+-- Examples:
+--
+-- > needlePrefix "cd" "abcde" = "ab"
+--
+-- > needlePrefix "ab" "abc" = ""
+--
+-- > needlePrefix "ab" "xxab" = "xx"
+--
+-- > needlePrefix "a" "xx" = "xx"
+needlePrefix :: String -> String -> Maybe String
+needlePrefix needle haystack = go [] haystack
+  where
+    go _   []                     = Nothing
+    go acc xss@(x:xs)
+        | needle `isPrefixOf` xss = Just $ reverse acc
+        | otherwise               = go (x : acc) xs